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Vol. 50 N° 22 - Novembre 2011 [texte imprimé] . - 2012 . - p. 12311-12844 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierControlled size silver nanoparticles synthesis with water - in - oil microemulsion method / Jignasa N. Solanki in Industrial & engineering chemistry research, Vol. 50 N° 22 (Novembre 2011)
Titre : Controlled size silver nanoparticles synthesis with water - in - oil microemulsion method : a topical review Type de document : texte imprimé Auteurs : Jignasa N. Solanki, Auteur ; Zagabathuni Venkata Panchakshari Murthy, Auteur Année de publication : 2012 Article en page(s) : pp. 12311–12323 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanoparticles Microemulsion Résumé : Synthesis of noble metallic nanoparticles, in general, and silver nanoparticles (SNPs), in particular, currently are of special interest. In the present paper, an overview of the enhanced properties of SNPs and consequential applications of SNPs are discussed. Common synthesis methods and their comparison with the microemulsion technology, particularly advantages of SNPs formation with microemulsion technology, are discussed. A brief overview of the basics of microemulsion technology for nanoparticles formation is also presented. The complete topical review of microemulsion synthesis technique used to date for the generation of SNPs is discussed comprehensively. Control parameters have been explicated for influencing size, size uniformity, and stability aspects of the SNPs reported in the literature, allowing a tailored synthesis for specific application. Recent modifications made on the synthesis of SNPs to obtain monodisperse, high yield and stability are also discussed. Lastly, some future trends and perspectives in these research areas are outlined. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201649x
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12311–12323[article] Controlled size silver nanoparticles synthesis with water - in - oil microemulsion method : a topical review [texte imprimé] / Jignasa N. Solanki, Auteur ; Zagabathuni Venkata Panchakshari Murthy, Auteur . - 2012 . - pp. 12311–12323.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12311–12323
Mots-clés : Nanoparticles Microemulsion Résumé : Synthesis of noble metallic nanoparticles, in general, and silver nanoparticles (SNPs), in particular, currently are of special interest. In the present paper, an overview of the enhanced properties of SNPs and consequential applications of SNPs are discussed. Common synthesis methods and their comparison with the microemulsion technology, particularly advantages of SNPs formation with microemulsion technology, are discussed. A brief overview of the basics of microemulsion technology for nanoparticles formation is also presented. The complete topical review of microemulsion synthesis technique used to date for the generation of SNPs is discussed comprehensively. Control parameters have been explicated for influencing size, size uniformity, and stability aspects of the SNPs reported in the literature, allowing a tailored synthesis for specific application. Recent modifications made on the synthesis of SNPs to obtain monodisperse, high yield and stability are also discussed. Lastly, some future trends and perspectives in these research areas are outlined. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201649x Exemplaires
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Titre : Understanding hydrogen in bayer process emissions. 1. hydrogen production during the degradation of hydroxycarboxylic acids in sodium hydroxide solutions Type de document : texte imprimé Auteurs : Allan Costine, Auteur ; Joanne S.C. Loh, Auteur ; Greg Power, Auteur Année de publication : 2012 Article en page(s) : pp. 12324–12333 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrogen Hydroxycarboxylic Acids Résumé : The formation of potentially explosive gas mixtures during Bayer process digestion and the wet oxidation of Bayer process liquors underscores the need for an improved understanding of the degradation reactions of organic compounds that produce flammable gases. This study is the first of a series investigating the production of hydrogen from different classes of organic compounds in sodium hydroxide solutions. The alkaline degradation of a range of aliphatic and aromatic carboxylates and hydroxycarboxylates was investigated under anaerobic conditions in an autoclave. It was found that aliphatic C4 carboxylates possessing a single β-hydroxy substituent are particularly reactive under these conditions, generating hydrogen gas and a range of low molecular weight (LMW) carboxylates. The effect of temperature (175–275 °C) and NaOH concentration (0–6 M) on the degradation of 3-hydroxybutanoate and hydroxybutanedioate (malate) was investigated in detail for reaction times up to 120 min. Under conditions that promote the total degradation of the organic compound, the β-hydroxycarboxylates have similar hydrogen production capacities, each generating about 1 mol of hydrogen gas per mole of organic compound consumed. The results provide direct evidence for an ionic degradation mechanism involving base-catalyzed oxidation by water, consistent with the stoichiometry of the formation of hydrogen gas and the other main reaction products (LMW carboxylates). These findings have important implications for the production of hydrogen in Bayer process digestion and the safe application of wet oxidation technologies for the treatment of organic compounds in alkaline liquors, such as those found in the Bayer and Kraft processes. The results also shed new light on the mechanism of hydrogen production during the base-catalyzed gasification of biomass at low temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201387x
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12324–12333[article] Understanding hydrogen in bayer process emissions. 1. hydrogen production during the degradation of hydroxycarboxylic acids in sodium hydroxide solutions [texte imprimé] / Allan Costine, Auteur ; Joanne S.C. Loh, Auteur ; Greg Power, Auteur . - 2012 . - pp. 12324–12333.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12324–12333
Mots-clés : Hydrogen Hydroxycarboxylic Acids Résumé : The formation of potentially explosive gas mixtures during Bayer process digestion and the wet oxidation of Bayer process liquors underscores the need for an improved understanding of the degradation reactions of organic compounds that produce flammable gases. This study is the first of a series investigating the production of hydrogen from different classes of organic compounds in sodium hydroxide solutions. The alkaline degradation of a range of aliphatic and aromatic carboxylates and hydroxycarboxylates was investigated under anaerobic conditions in an autoclave. It was found that aliphatic C4 carboxylates possessing a single β-hydroxy substituent are particularly reactive under these conditions, generating hydrogen gas and a range of low molecular weight (LMW) carboxylates. The effect of temperature (175–275 °C) and NaOH concentration (0–6 M) on the degradation of 3-hydroxybutanoate and hydroxybutanedioate (malate) was investigated in detail for reaction times up to 120 min. Under conditions that promote the total degradation of the organic compound, the β-hydroxycarboxylates have similar hydrogen production capacities, each generating about 1 mol of hydrogen gas per mole of organic compound consumed. The results provide direct evidence for an ionic degradation mechanism involving base-catalyzed oxidation by water, consistent with the stoichiometry of the formation of hydrogen gas and the other main reaction products (LMW carboxylates). These findings have important implications for the production of hydrogen in Bayer process digestion and the safe application of wet oxidation technologies for the treatment of organic compounds in alkaline liquors, such as those found in the Bayer and Kraft processes. The results also shed new light on the mechanism of hydrogen production during the base-catalyzed gasification of biomass at low temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201387x Exemplaires
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Titre : Understanding hydrogen in bayer process emissions. 2. hydrogen production during the degradation of unsaturated carboxylic acids in sodium hydroxide solutions Type de document : texte imprimé Auteurs : Allan Costine, Auteur ; Joanne S.C. Loh, Auteur ; Greg Power, Auteur Année de publication : 2012 Article en page(s) : pp. 12334–12342 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrogen Carboxylic acids Sodium hydroxide Résumé : This is the second in a series of studies of the production of hydrogen from the degradation of organic compounds in sodium hydroxide solutions. Unsaturated carboxylates, which are intermediate products in the wet oxidation of the types of monoaromatic compounds typically present in Bayer process liquors, have been found to produce significant amounts of hydrogen during alkaline degradation. The alkaline degradation of nine unsaturated carboxylates was investigated under anaerobic conditions in an autoclave, and the effect of temperature (175–275 °C) and NaOH concentration (0–6 M) on the degradation of acrylate, 2-butenoate, maleate, and 2-hexenoate was studied in detail for reaction times up to 120 min. All of the compounds investigated decompose to produce about 1 mol of hydrogen gas per mole of organic compound consumed, as well as a range of low molecular weight (LMW) carboxylates. The stoichiometries of the formation of hydrogen and LMW carboxylates from the unsaturated carboxylates observed here are consistent with the regioselective hydration of the C═C double bond to form the corresponding β-hydroxycarboxylates, which then undergo further degradation by an ionic mechanism involving base-catalyzed oxidation by water. These findings significantly advance the understanding of the production of hydrogen in Bayer process digestion and have implications for the safe application of wet oxidation of Bayer process liquors. The results also advance the fundamental understanding of the alkaline degradation of α,β-unsaturated carbonyl compounds in general. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201388c
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12334–12342[article] Understanding hydrogen in bayer process emissions. 2. hydrogen production during the degradation of unsaturated carboxylic acids in sodium hydroxide solutions [texte imprimé] / Allan Costine, Auteur ; Joanne S.C. Loh, Auteur ; Greg Power, Auteur . - 2012 . - pp. 12334–12342.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12334–12342
Mots-clés : Hydrogen Carboxylic acids Sodium hydroxide Résumé : This is the second in a series of studies of the production of hydrogen from the degradation of organic compounds in sodium hydroxide solutions. Unsaturated carboxylates, which are intermediate products in the wet oxidation of the types of monoaromatic compounds typically present in Bayer process liquors, have been found to produce significant amounts of hydrogen during alkaline degradation. The alkaline degradation of nine unsaturated carboxylates was investigated under anaerobic conditions in an autoclave, and the effect of temperature (175–275 °C) and NaOH concentration (0–6 M) on the degradation of acrylate, 2-butenoate, maleate, and 2-hexenoate was studied in detail for reaction times up to 120 min. All of the compounds investigated decompose to produce about 1 mol of hydrogen gas per mole of organic compound consumed, as well as a range of low molecular weight (LMW) carboxylates. The stoichiometries of the formation of hydrogen and LMW carboxylates from the unsaturated carboxylates observed here are consistent with the regioselective hydration of the C═C double bond to form the corresponding β-hydroxycarboxylates, which then undergo further degradation by an ionic mechanism involving base-catalyzed oxidation by water. These findings significantly advance the understanding of the production of hydrogen in Bayer process digestion and have implications for the safe application of wet oxidation of Bayer process liquors. The results also advance the fundamental understanding of the alkaline degradation of α,β-unsaturated carbonyl compounds in general. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201388c Exemplaires
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Titre : Novel route for the synthesis of methyl propionate from 3 - pentanone with dimethyl carbonate over solid bases Type de document : texte imprimé Auteurs : Zhi Chen, Auteur ; Dudu Wu, Auteur Année de publication : 2012 Article en page(s) : pp. 12343-12348 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Methyl Dimethyl Carbonate Résumé : A novel and simple route for the synthesis of methyl propionate by the methoxycarbonylation of 3-pentanone with dimethyl carbonate in the presence of solid base catalysts was developed. Solid bases with moderate strength (such as MgO) facilitated the formation of methyl propionate, and the yield of methyl propionate could be linearly correlated with the amount of moderate basic sites. The function of basic catalysts was mainly attributed to the activation of 3-pentanone through the abstraction of the α-H by base sites. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1006933
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12343-12348[article] Novel route for the synthesis of methyl propionate from 3 - pentanone with dimethyl carbonate over solid bases [texte imprimé] / Zhi Chen, Auteur ; Dudu Wu, Auteur . - 2012 . - pp. 12343-12348.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12343-12348
Mots-clés : Methyl Dimethyl Carbonate Résumé : A novel and simple route for the synthesis of methyl propionate by the methoxycarbonylation of 3-pentanone with dimethyl carbonate in the presence of solid base catalysts was developed. Solid bases with moderate strength (such as MgO) facilitated the formation of methyl propionate, and the yield of methyl propionate could be linearly correlated with the amount of moderate basic sites. The function of basic catalysts was mainly attributed to the activation of 3-pentanone through the abstraction of the α-H by base sites. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1006933 Exemplaires
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Titre : Fractionation of lignocellulosic materials with ionic liquids. 1. effect of mechanical treatment Type de document : texte imprimé Auteurs : Timo Leskinen, Auteur ; Alistair W. T. King, Auteur ; Ilkka Kilpelainen, Auteur Année de publication : 2012 Article en page(s) : pp. 12349-12357 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mechanical treatment Ionic liquid Speciation Résumé : The selective precipitation of wood dissolved in 1-allyl-3-methylimidazolium chloride ([amino]Cl) with a nonsolvent is a straightforward method for fractionating lignocellulosic components. In this study we have solvated and precipitated fractions of pulverized Norway spruce (Picea abies) and Eucalyptus grandis wood. This was achieved by agitating and heating the lignocellulosic materials in [amim]Cl followed by precipitation using nonsolvents, such as acetonitrile (MeCN) and water. Water was also used to extract material, which was determined to be high molecular weight galactoglucomannan. Products were analyzed by benzoylation followed by size-exclusion chromatography (SEC) and IR. It was found that the selectivity of precipitation was not significantly dependent upon the chemical composition of the precipitating components. The efficiency of precipitation was found to be dependent upon molecular weight, with the dissolved higher molecular weight and partially soluble wood components precipitating first. Moreover, when coarse sawdust samples were fractionated, the selective dissolution of cellulose from the fiber was observed, which allowed for the regeneration of a fraction of delignified and bleachable cellulose. Additionally, finely milled softwood samples, with demonstrated narrowly distributed low molecular weights, did not efficiently fractionate most likely due to the presence of an extensive lignin-carbohydrate complex (LCC) network. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745705
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12349-12357[article] Fractionation of lignocellulosic materials with ionic liquids. 1. effect of mechanical treatment [texte imprimé] / Timo Leskinen, Auteur ; Alistair W. T. King, Auteur ; Ilkka Kilpelainen, Auteur . - 2012 . - pp. 12349-12357.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12349-12357
Mots-clés : Mechanical treatment Ionic liquid Speciation Résumé : The selective precipitation of wood dissolved in 1-allyl-3-methylimidazolium chloride ([amino]Cl) with a nonsolvent is a straightforward method for fractionating lignocellulosic components. In this study we have solvated and precipitated fractions of pulverized Norway spruce (Picea abies) and Eucalyptus grandis wood. This was achieved by agitating and heating the lignocellulosic materials in [amim]Cl followed by precipitation using nonsolvents, such as acetonitrile (MeCN) and water. Water was also used to extract material, which was determined to be high molecular weight galactoglucomannan. Products were analyzed by benzoylation followed by size-exclusion chromatography (SEC) and IR. It was found that the selectivity of precipitation was not significantly dependent upon the chemical composition of the precipitating components. The efficiency of precipitation was found to be dependent upon molecular weight, with the dissolved higher molecular weight and partially soluble wood components precipitating first. Moreover, when coarse sawdust samples were fractionated, the selective dissolution of cellulose from the fiber was observed, which allowed for the regeneration of a fraction of delignified and bleachable cellulose. Additionally, finely milled softwood samples, with demonstrated narrowly distributed low molecular weights, did not efficiently fractionate most likely due to the presence of an extensive lignin-carbohydrate complex (LCC) network. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745705 Exemplaires
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Titre : Temperature - swing adsorption of proteins in water using cationic copolymer - grafted silica particles Type de document : texte imprimé Auteurs : Shintaro Morisada, Auteur ; Ken-ichiro Namazuda, Auteur ; Shitoka Suzuki, Auteur Année de publication : 2012 Article en page(s) : pp. 12358–12365 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Copolymer Résumé : We have prepared silica particles grafted with poly(N-isopropylacrylamide) (PNIPA) copolymers as adsorbent for the temperature-swing adsorption of bovine serum albumin (BSA) in water, where vinylbenzyl trimethylammonium chloride (VBTA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), or N,N-dimethylacrylamide (DMAA) was employed as a comonomer. The surface potentials of PNIPA-grafted and P(NIPA-co-DMAA)-grafted silica particles in water at 298 and 313 K were negative, while those of P(NIPA-co-VBTA)-grafted silica particle were positive, because VBTA is a quaternary ammonium salt and positively charged in aqueous solutions. As for the P(NIPA-co-DMAEMA)-grafted silica particle, the surface potential changed from positive to near zero with increasing temperature from 298 K to 313 K. This may be because the coil-to-globule transition of grafted copolymers leads to the dehydration and deprotonation of DMAEMA group, which is a tertiary amine and can be positively charged only in the aqueous phase. Although PNIPA-grafted and P(NIPA-co-DMAA)-grafted silica particles failed to adsorb BSA, P(NIPA-co-VBTA)-grafted and P(NIPA-co-DMAEMA)-grafted silica particles adsorbed BSA, indicating that BSA is adsorbed by the electrostatic attraction between the negatively charged BSA and the positively charged copolymers on the silica surface. Moreover, P(NIPA-co-VBTA)-grafted and P(NIPA-co-DMAEMA)-grafted silica particles repeatedly adsorbed BSA at 298 K and desorbed some of the preadsorbed BSA at 313 K via the temperature-swing operation. This BSA desorption may result from the decrease in the number of the positively charged groups accessible to BSA due to the coil-to-globule transition of the grafted copolymers with increasing temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200779w
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12358–12365[article] Temperature - swing adsorption of proteins in water using cationic copolymer - grafted silica particles [texte imprimé] / Shintaro Morisada, Auteur ; Ken-ichiro Namazuda, Auteur ; Shitoka Suzuki, Auteur . - 2012 . - pp. 12358–12365.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12358–12365
Mots-clés : Adsorption Copolymer Résumé : We have prepared silica particles grafted with poly(N-isopropylacrylamide) (PNIPA) copolymers as adsorbent for the temperature-swing adsorption of bovine serum albumin (BSA) in water, where vinylbenzyl trimethylammonium chloride (VBTA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), or N,N-dimethylacrylamide (DMAA) was employed as a comonomer. The surface potentials of PNIPA-grafted and P(NIPA-co-DMAA)-grafted silica particles in water at 298 and 313 K were negative, while those of P(NIPA-co-VBTA)-grafted silica particle were positive, because VBTA is a quaternary ammonium salt and positively charged in aqueous solutions. As for the P(NIPA-co-DMAEMA)-grafted silica particle, the surface potential changed from positive to near zero with increasing temperature from 298 K to 313 K. This may be because the coil-to-globule transition of grafted copolymers leads to the dehydration and deprotonation of DMAEMA group, which is a tertiary amine and can be positively charged only in the aqueous phase. Although PNIPA-grafted and P(NIPA-co-DMAA)-grafted silica particles failed to adsorb BSA, P(NIPA-co-VBTA)-grafted and P(NIPA-co-DMAEMA)-grafted silica particles adsorbed BSA, indicating that BSA is adsorbed by the electrostatic attraction between the negatively charged BSA and the positively charged copolymers on the silica surface. Moreover, P(NIPA-co-VBTA)-grafted and P(NIPA-co-DMAEMA)-grafted silica particles repeatedly adsorbed BSA at 298 K and desorbed some of the preadsorbed BSA at 313 K via the temperature-swing operation. This BSA desorption may result from the decrease in the number of the positively charged groups accessible to BSA due to the coil-to-globule transition of the grafted copolymers with increasing temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200779w Exemplaires
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Titre : Preparation of thiocyanate - retaining tannin gel for adsorption recovery of palladium from strong hydrochloric acid solutions Type de document : texte imprimé Auteurs : Shintaro Morisada, Auteur ; Yoen-Ho Kim, Auteur ; Shinpei Yakuwa, Auteur Année de publication : 2012 Article en page(s) : pp. 12366–12371 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Preparation Résumé : A tannin gel (TG) synthesized from condensed tannin molecules has a remarkable ability to adsorb various metal ions in aqueous solutions. In the present study, we have introduced thiocyanate ions (SCN–) into the TG by adsorption process in acidic thiocyanate solutions to improve its adsorbability for palladium ion, Pd(II). To determine the optimum conditions for preparing the SCN–-retaining tannin gel (SCN-TG), we have investigated the introduction mechanism of SCN– into the TG at 298 K and HCl concentrations less than or equal to 1 M, where the decomposition of SCN– can be negligible. The adsorption amount of SCN– onto the TG increased with increasing HCl concentration, indicating that SCN– is adsorbed onto the TG through the electrostatic attraction between anionic SCN– and the protonated hydroxy groups in the TG at higher HCl concentrations. Using the resultant SCN-TG and the TG, we have conducted the Pd(II) adsorption experiment at molar-level concentrations of HCl and found that the SCN-TG can adsorb Pd(II) efficiently, whereas the TG adsorbs almost no Pd(II). Besides, the adsorbability of the SCN-TG for Pd(II) decreased only slightly with increasing HCl concentration up to at least 5 M. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745707
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12366–12371[article] Preparation of thiocyanate - retaining tannin gel for adsorption recovery of palladium from strong hydrochloric acid solutions [texte imprimé] / Shintaro Morisada, Auteur ; Yoen-Ho Kim, Auteur ; Shinpei Yakuwa, Auteur . - 2012 . - pp. 12366–12371.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12366–12371
Mots-clés : Adsorption Preparation Résumé : A tannin gel (TG) synthesized from condensed tannin molecules has a remarkable ability to adsorb various metal ions in aqueous solutions. In the present study, we have introduced thiocyanate ions (SCN–) into the TG by adsorption process in acidic thiocyanate solutions to improve its adsorbability for palladium ion, Pd(II). To determine the optimum conditions for preparing the SCN–-retaining tannin gel (SCN-TG), we have investigated the introduction mechanism of SCN– into the TG at 298 K and HCl concentrations less than or equal to 1 M, where the decomposition of SCN– can be negligible. The adsorption amount of SCN– onto the TG increased with increasing HCl concentration, indicating that SCN– is adsorbed onto the TG through the electrostatic attraction between anionic SCN– and the protonated hydroxy groups in the TG at higher HCl concentrations. Using the resultant SCN-TG and the TG, we have conducted the Pd(II) adsorption experiment at molar-level concentrations of HCl and found that the SCN-TG can adsorb Pd(II) efficiently, whereas the TG adsorbs almost no Pd(II). Besides, the adsorbability of the SCN-TG for Pd(II) decreased only slightly with increasing HCl concentration up to at least 5 M. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745707 Exemplaires
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Titre : Effect of initial pH adjustment on hydrolysis and acidification of sludge by ultrasonic pretreatment Type de document : texte imprimé Auteurs : Xiao-Rong Kang, Auteur ; Guang-Ming Zhang, Auteur ; Lin Chen, Auteur Année de publication : 2012 Article en page(s) : pp. 12372–12378 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pretreatment Acidification Hydrolysis pH Résumé : Batch tests were carried out to analyze the effect of pH in the range of 7-12 on the hydrolysis and acidification of sludge at room temperature. Ultrasonic pretreatment was conducted to disintegrate waste activated sludge (WAS) and accelerate WAS hydrolysis. The experimental results showed that the sludge with ultrasonic pretreatment was readily degraded in the hydrolysis and acidification process, and more organic substances were released with increase of initial pH. The optimal initial pH for sludge acidification was 11, and the short chain fatty acids (SCFAs) concentration reached about 1751 mg/L after 15 days of hydrolysis and acidification. Phosphorus release was investigated during hydrolysis and acidification at any pH adjustment. The SCFAs mainly consisted of acetic and propionic, accounting for 74.6-84% of total SCFAs. Three microbial species, including Bacteroidetes, γ-proteobacteria, and β-proteobacteria, were involved in different pH environments of the hydrolysis and acidification process, and, simultaneously, the three species were identified as being responsible for SCFAs accumulation and protein degradation. This study indicated that the combination of ultrasonic pretreatment, alkaline adjustment for hydrolysis, and acidification of WAS was an appropriate method for SCFAs accumulation and contributed to the demand of carbon source for WWTPs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745708
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12372–12378[article] Effect of initial pH adjustment on hydrolysis and acidification of sludge by ultrasonic pretreatment [texte imprimé] / Xiao-Rong Kang, Auteur ; Guang-Ming Zhang, Auteur ; Lin Chen, Auteur . - 2012 . - pp. 12372–12378.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12372–12378
Mots-clés : Pretreatment Acidification Hydrolysis pH Résumé : Batch tests were carried out to analyze the effect of pH in the range of 7-12 on the hydrolysis and acidification of sludge at room temperature. Ultrasonic pretreatment was conducted to disintegrate waste activated sludge (WAS) and accelerate WAS hydrolysis. The experimental results showed that the sludge with ultrasonic pretreatment was readily degraded in the hydrolysis and acidification process, and more organic substances were released with increase of initial pH. The optimal initial pH for sludge acidification was 11, and the short chain fatty acids (SCFAs) concentration reached about 1751 mg/L after 15 days of hydrolysis and acidification. Phosphorus release was investigated during hydrolysis and acidification at any pH adjustment. The SCFAs mainly consisted of acetic and propionic, accounting for 74.6-84% of total SCFAs. Three microbial species, including Bacteroidetes, γ-proteobacteria, and β-proteobacteria, were involved in different pH environments of the hydrolysis and acidification process, and, simultaneously, the three species were identified as being responsible for SCFAs accumulation and protein degradation. This study indicated that the combination of ultrasonic pretreatment, alkaline adjustment for hydrolysis, and acidification of WAS was an appropriate method for SCFAs accumulation and contributed to the demand of carbon source for WWTPs. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745708 Exemplaires
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Titre : Bisthiocarbohydrazones as colorimetric and “Turn on” fluorescent chemosensors for selective recognition of fluoride Type de document : texte imprimé Auteurs : Saravana Loganathan Ashok Kumar, Auteur ; Ramalingam Tamilarasan, Auteur ; Moorthy Saravana Kumar, Auteur Année de publication : 2012 Article en page(s) : pp. 12379-12383 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bisthiocarbohydrazone Heterocyclic Résumé : Bisthiocarbohydrazone derivatives of two heterocyclic ketones were designed and synthesized to selectively sense fluoride ion from a biologically competing solvent dimethylsulfoxide (DMSO). The selective recognition of fluoride is clearly visible to the naked eye with a distinct color change. The recognition mechanism has been investigated by UV–visible, fluorescence spectroscopy, and 1H NMR titration experiments. From the Benesi–Hidebrand equation and Job's plot, it was inferred that both compounds bind to fluoride with a 1:1 stoichiometry. 1H NMR titration data indicates deprotonation of the NH protons by fluoride as a prominent step in the recognition. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2013696
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12379-12383[article] Bisthiocarbohydrazones as colorimetric and “Turn on” fluorescent chemosensors for selective recognition of fluoride [texte imprimé] / Saravana Loganathan Ashok Kumar, Auteur ; Ramalingam Tamilarasan, Auteur ; Moorthy Saravana Kumar, Auteur . - 2012 . - pp. 12379-12383.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12379-12383
Mots-clés : Bisthiocarbohydrazone Heterocyclic Résumé : Bisthiocarbohydrazone derivatives of two heterocyclic ketones were designed and synthesized to selectively sense fluoride ion from a biologically competing solvent dimethylsulfoxide (DMSO). The selective recognition of fluoride is clearly visible to the naked eye with a distinct color change. The recognition mechanism has been investigated by UV–visible, fluorescence spectroscopy, and 1H NMR titration experiments. From the Benesi–Hidebrand equation and Job's plot, it was inferred that both compounds bind to fluoride with a 1:1 stoichiometry. 1H NMR titration data indicates deprotonation of the NH protons by fluoride as a prominent step in the recognition. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2013696 Exemplaires
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Titre : Core - in - shell CaO / CuO - Based composite for CO2 capture Type de document : texte imprimé Auteurs : Vasilije Manovic, Auteur ; Yinghai Wu, Auteur ; Ian He, Auteur Année de publication : 2012 Article en page(s) : pp. 12384–12391 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Composite materials Résumé : This paper describes the preparation of composite materials containing both CaO as a reversible CO2 sorbent and CuO, serving as an oxygen carrier, which allows the spent Ca sorbent to be regenerated in a fuel gas stream after it has been used for CO2 capture. Calcium aluminate cement is used as a support to enhance pellet strength. The pellets were prepared in a mechanical pelletizer for granulation of powdered materials with addition of spray water. Three types of pellets were prepared: (i) core-in-shell with 50% CuO and 50% CaO (75% CuO and 25% CaO in the core), (ii) core-in-shell with 50% CuO, 40% CaO, and 10% cement (75% CuO and 25% CaO in the core), and (iii) homogeneous pellets with 50% CuO, 40% CaO, and 10% cement addition as a binder. CO2/O2 carrying activity of the pellets was then tested in a thermogravimetric analyzer (TGA). The attrition resistance of the obtained material was examined during attrition tests in a bubbling fluidized bed (i.d. 50 mm). The oxygen carrying capacity of pellets indicates that 25% CaO in the core is sufficient to support the CuO and prevent decay of its activity as an oxygen carrier during reduction/oxidation cycles. To demonstrate that the pellets produced actually have a core-in-shell pattern, larger cross-sectioned particles were analyzed using the scanning electron microscope/energy dispersive X-ray method (SEM/EDX). The SEM/EDX analyses clearly showed different morphology and elemental composition of the core and shell, with a higher content of CuO in the core. The results of attrition tests showed that after fluidization for 2 h, particle size distribution changed negligibly and high temperature did not cause significantly more pronounced attrition. These tests clearly showed that the procedure employed is suitable for large-scale preparation of core-in-shell CaO/CuO-based pellets which have numerous benefits. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201427g
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12384–12391[article] Core - in - shell CaO / CuO - Based composite for CO2 capture [texte imprimé] / Vasilije Manovic, Auteur ; Yinghai Wu, Auteur ; Ian He, Auteur . - 2012 . - pp. 12384–12391.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12384–12391
Mots-clés : Composite materials Résumé : This paper describes the preparation of composite materials containing both CaO as a reversible CO2 sorbent and CuO, serving as an oxygen carrier, which allows the spent Ca sorbent to be regenerated in a fuel gas stream after it has been used for CO2 capture. Calcium aluminate cement is used as a support to enhance pellet strength. The pellets were prepared in a mechanical pelletizer for granulation of powdered materials with addition of spray water. Three types of pellets were prepared: (i) core-in-shell with 50% CuO and 50% CaO (75% CuO and 25% CaO in the core), (ii) core-in-shell with 50% CuO, 40% CaO, and 10% cement (75% CuO and 25% CaO in the core), and (iii) homogeneous pellets with 50% CuO, 40% CaO, and 10% cement addition as a binder. CO2/O2 carrying activity of the pellets was then tested in a thermogravimetric analyzer (TGA). The attrition resistance of the obtained material was examined during attrition tests in a bubbling fluidized bed (i.d. 50 mm). The oxygen carrying capacity of pellets indicates that 25% CaO in the core is sufficient to support the CuO and prevent decay of its activity as an oxygen carrier during reduction/oxidation cycles. To demonstrate that the pellets produced actually have a core-in-shell pattern, larger cross-sectioned particles were analyzed using the scanning electron microscope/energy dispersive X-ray method (SEM/EDX). The SEM/EDX analyses clearly showed different morphology and elemental composition of the core and shell, with a higher content of CuO in the core. The results of attrition tests showed that after fluidization for 2 h, particle size distribution changed negligibly and high temperature did not cause significantly more pronounced attrition. These tests clearly showed that the procedure employed is suitable for large-scale preparation of core-in-shell CaO/CuO-based pellets which have numerous benefits. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201427g Exemplaires
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Titre : Improved inheritance algorithm for the assembly of coal fragments Type de document : texte imprimé Auteurs : Zhao Lei, Auteur ; Bolun Yang, Auteur ; Jianwei Li, Auteur Année de publication : 2012 Article en page(s) : pp. 12392–12399 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Coal Algorithm Résumé : There are many methods to simulate coal structure that might be beneficial to coal technologies. However, they often suffer from producing an impractical structure and a large calculation time and could not be applied to most rank coal Hence, the hybrid inheritance algorithms combined with Elitist strategy (HIA-ES) and Monte Carlo and Elitist Strategy (HIA-MC-ES) are proposed to simulate the coal structure. The reported fragment structures of the coal macromolecule are summarized, and the fragment structure is accurately quantified with an adjacency matrix, an atom identification vector, bonding parameters, a bond characteristic index, and a functional group characteristic parameter, respectively. The humic acid (HA) is used to test the effectiveness of two algorithms since HA has the similar fragment structures with coal With the use of the method of HIA-ES, the numbers of fragment structures is gained. Then, the parameters of the simulated structures are obtained with the HIA-MC-ES method. Simulated HA and Shenfu coal structures are highly similar with the reported results, indicating that the two novel hybrid inheritance algorithms are effective to simulate a molecular structure for the most rank coal. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745711
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12392–12399[article] Improved inheritance algorithm for the assembly of coal fragments [texte imprimé] / Zhao Lei, Auteur ; Bolun Yang, Auteur ; Jianwei Li, Auteur . - 2012 . - pp. 12392–12399.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12392–12399
Mots-clés : Coal Algorithm Résumé : There are many methods to simulate coal structure that might be beneficial to coal technologies. However, they often suffer from producing an impractical structure and a large calculation time and could not be applied to most rank coal Hence, the hybrid inheritance algorithms combined with Elitist strategy (HIA-ES) and Monte Carlo and Elitist Strategy (HIA-MC-ES) are proposed to simulate the coal structure. The reported fragment structures of the coal macromolecule are summarized, and the fragment structure is accurately quantified with an adjacency matrix, an atom identification vector, bonding parameters, a bond characteristic index, and a functional group characteristic parameter, respectively. The humic acid (HA) is used to test the effectiveness of two algorithms since HA has the similar fragment structures with coal With the use of the method of HIA-ES, the numbers of fragment structures is gained. Then, the parameters of the simulated structures are obtained with the HIA-MC-ES method. Simulated HA and Shenfu coal structures are highly similar with the reported results, indicating that the two novel hybrid inheritance algorithms are effective to simulate a molecular structure for the most rank coal. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745711 Exemplaires
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Titre : Modeling of dye uptake rate, related interactions, and binding energy estimation in leather matrix using protein based nanoparticle polymer Type de document : texte imprimé Auteurs : James Kanagaraj, Auteur ; Rames Chandra Panda, Auteur Année de publication : 2012 Article en page(s) : pp. 12400–12408 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanoparticle Uptake Dyes Modeling Résumé : A nanoparticle polymer (NPP) is prepared from amino acids of keratin hydrolysate, obtained after enzymatic degradation. The NPP copolymer chain is made up of two types of monomers, viz. an acrylic ester and an amino acid derivative of keratin hydrolysate. NPP was synthesized using microemulsion polymerization method. The developed NPP exhibits narrow particle size distribution with particle size of 60 nm. The NPP is a free-flowing liquid with flow characteristics almost similar to water, as shown from its low relative viscosity (ηr) of 1.02 at 25 °C. The zeta potential of NPP at -30.2 mV demonstrates anionic nature of the copolymer particle and this may be provided from amino acid derived monomer. The NPP possesses a high molecular weight copolymer in aqueous medium and carboxyl groups as an active site for interaction. The dyeing process carried out after the treatment of NPP enhanced dye uptake. From PM6 semi empirical quantum mechanical level; the interaction of NPP with dye showed four reactive sites. The geometries of the reactive sites were found out. The results showed that binding energies of site 2 and 3 were higher in comparison with those of 1 and 4. The kinetics and color measurement study showed that dye uptake was enhanced by using NPP. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745712
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12400–12408[article] Modeling of dye uptake rate, related interactions, and binding energy estimation in leather matrix using protein based nanoparticle polymer [texte imprimé] / James Kanagaraj, Auteur ; Rames Chandra Panda, Auteur . - 2012 . - pp. 12400–12408.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12400–12408
Mots-clés : Nanoparticle Uptake Dyes Modeling Résumé : A nanoparticle polymer (NPP) is prepared from amino acids of keratin hydrolysate, obtained after enzymatic degradation. The NPP copolymer chain is made up of two types of monomers, viz. an acrylic ester and an amino acid derivative of keratin hydrolysate. NPP was synthesized using microemulsion polymerization method. The developed NPP exhibits narrow particle size distribution with particle size of 60 nm. The NPP is a free-flowing liquid with flow characteristics almost similar to water, as shown from its low relative viscosity (ηr) of 1.02 at 25 °C. The zeta potential of NPP at -30.2 mV demonstrates anionic nature of the copolymer particle and this may be provided from amino acid derived monomer. The NPP possesses a high molecular weight copolymer in aqueous medium and carboxyl groups as an active site for interaction. The dyeing process carried out after the treatment of NPP enhanced dye uptake. From PM6 semi empirical quantum mechanical level; the interaction of NPP with dye showed four reactive sites. The geometries of the reactive sites were found out. The results showed that binding energies of site 2 and 3 were higher in comparison with those of 1 and 4. The kinetics and color measurement study showed that dye uptake was enhanced by using NPP. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745712 Exemplaires
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Titre : Kinetics of the reaction of dense CaO particles with SO2 Type de document : texte imprimé Auteurs : Shin-Min Shih, Auteur ; Jong-Cherng Lai, Auteur ; Chih-Hsiang Yang, Auteur Année de publication : 2012 Article en page(s) : pp. 12409–12420 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Dioxide Thermogravimetric Résumé : The kinetics of the reaction of dense CaO particles (2.5 mm dia.) with sulfur dioxide was studied using a thermogravimetric technique under the conditions of 750–950 °C, 1000–5000 ppm SO2, and 6 h reaction time. The growth of CaSO4 product layer was observed using a scanning electron microscope. The effect of internal structural change due to reaction, which complicates the kinetic analysis of porous particles, was eliminated in the present case. The thickening of the product layer behaved as the shrinking-core type reaction. The product layer was composed of many CaSO4 grains, the size of which increased singnificantly with increasing temperature. The long-term reaction kinetics was well described by the shrinking-core model for changing particle size by considering the product layer diffusion and intrinsic chemical reaction. The apparent reaction order of SO2 was 0.3 and close to 1.0 only at low CaO conversions. The values of chemical reaction rate constant and the activation energy for chemical reaction rate constant or product layer diffusivity were in the range reported by previous investigators, but the values of the product layer diffusivity were much higher. The model equations for the case involving the inward or outward solid-state diffusion of ions were derived. The reaction kinetics can be explained by considering both the diffusion of Ca2+ and O2– ions and the diffusion of gaseous reactants. The product layer tended to fracture continually and form more cracks at higher temperatures, thus resulting in higher values of product layer diffusivity and a high activation energy for diffusivity, and leading to an apparent SO2 reaction order smaller than first order. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2009668
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12409–12420[article] Kinetics of the reaction of dense CaO particles with SO2 [texte imprimé] / Shin-Min Shih, Auteur ; Jong-Cherng Lai, Auteur ; Chih-Hsiang Yang, Auteur . - 2012 . - pp. 12409–12420.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12409–12420
Mots-clés : Kinetics Dioxide Thermogravimetric Résumé : The kinetics of the reaction of dense CaO particles (2.5 mm dia.) with sulfur dioxide was studied using a thermogravimetric technique under the conditions of 750–950 °C, 1000–5000 ppm SO2, and 6 h reaction time. The growth of CaSO4 product layer was observed using a scanning electron microscope. The effect of internal structural change due to reaction, which complicates the kinetic analysis of porous particles, was eliminated in the present case. The thickening of the product layer behaved as the shrinking-core type reaction. The product layer was composed of many CaSO4 grains, the size of which increased singnificantly with increasing temperature. The long-term reaction kinetics was well described by the shrinking-core model for changing particle size by considering the product layer diffusion and intrinsic chemical reaction. The apparent reaction order of SO2 was 0.3 and close to 1.0 only at low CaO conversions. The values of chemical reaction rate constant and the activation energy for chemical reaction rate constant or product layer diffusivity were in the range reported by previous investigators, but the values of the product layer diffusivity were much higher. The model equations for the case involving the inward or outward solid-state diffusion of ions were derived. The reaction kinetics can be explained by considering both the diffusion of Ca2+ and O2– ions and the diffusion of gaseous reactants. The product layer tended to fracture continually and form more cracks at higher temperatures, thus resulting in higher values of product layer diffusivity and a high activation energy for diffusivity, and leading to an apparent SO2 reaction order smaller than first order. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2009668 Exemplaires
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Titre : Kinetics and mechanism of oxidation of l - proline by N - bromosuccinimide in aqueous acidic medium Type de document : texte imprimé Auteurs : Alaa Eldin Mokhtar Abdel-Hady, Auteur Année de publication : 2012 Article en page(s) : pp. 12421-12425 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxidation Kinetics Résumé : Kinetics of oxidation of L-poline by N-bromosuccinimide (NBS) in aqueous acidic medium and water-alcohol solvent mixtures were performed. The reaction was first order dependent on both [proline] and [NBS]. The rate of reaction was inversely dependent upon [H+] through the pH range 2.6-3.3 and varied with the cosolvent according to the order MeOH > EtOH. The conjugate base of amino acid was considered as the main reactive species. An inner-sphere mechanism in which the conjugate base of amino acid was attached by NBS to form the precursor intermediate complex was proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745714
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12421-12425[article] Kinetics and mechanism of oxidation of l - proline by N - bromosuccinimide in aqueous acidic medium [texte imprimé] / Alaa Eldin Mokhtar Abdel-Hady, Auteur . - 2012 . - pp. 12421-12425.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12421-12425
Mots-clés : Oxidation Kinetics Résumé : Kinetics of oxidation of L-poline by N-bromosuccinimide (NBS) in aqueous acidic medium and water-alcohol solvent mixtures were performed. The reaction was first order dependent on both [proline] and [NBS]. The rate of reaction was inversely dependent upon [H+] through the pH range 2.6-3.3 and varied with the cosolvent according to the order MeOH > EtOH. The conjugate base of amino acid was considered as the main reactive species. An inner-sphere mechanism in which the conjugate base of amino acid was attached by NBS to form the precursor intermediate complex was proposed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745714 Exemplaires
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Titre : Autothermal reforming of methane in a proton - conducting ceramic membrane reactor Type de document : texte imprimé Auteurs : Jay Kniep, Auteur ; Matthew Anderson, Auteur ; Y. S. Lin, Auteur Année de publication : 2012 Article en page(s) : pp. 12426–12432 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Membrane reactor Ceramic materials Inorganic membrane Autothermic Reforming Résumé : Endothermic steam reforming of methane for hydrogen production requires heat input with selective oxidation of methane. Dense SrCe0.75Zr0.20Tm0.05O3-δ perovskite membranes were combined with a reforming catalyst to demonstrate the feasibility of a heat-exchange membrane reactor for steam reforming of methane coupled with selective oxidation of permeated hydrogen. The reforming catalyst used was a prereduced nickel based catalyst supported on γ-Al2O3. Hydrogen produced via the steam reforming of methane or water gas shift reaction was able to diffuse through the catalyst bed and transport through the membrane. The permeated hydrogen reacted with oxygen (from air) to produce heat for the steam reforming of methane on the other side of the membrane. The membrane reactor avoids the use of an expensive air separation unit to produce pure oxygen. The influence of experimental conditions, such as temperature, gas hourly space velocity, and the steam to carbon (S/C) ratio, on the membrane reactor was investigated. SrCe0.75Zr0.20Tm0.05O3-δ showed good chemical stability in steam reforming conditions as X-ray diffraction analysis of the membrane surface exposed to steam-reforming conditions for 425 h showed only minor CeO2 formation. The experimental data demonstrate the feasibility of using a proton conducting ceramic membrane in the heat-exchange membrane reactor for steam reforming of methane coupled with selective oxidation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745715
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12426–12432[article] Autothermal reforming of methane in a proton - conducting ceramic membrane reactor [texte imprimé] / Jay Kniep, Auteur ; Matthew Anderson, Auteur ; Y. S. Lin, Auteur . - 2012 . - pp. 12426–12432.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12426–12432
Mots-clés : Membrane reactor Ceramic materials Inorganic membrane Autothermic Reforming Résumé : Endothermic steam reforming of methane for hydrogen production requires heat input with selective oxidation of methane. Dense SrCe0.75Zr0.20Tm0.05O3-δ perovskite membranes were combined with a reforming catalyst to demonstrate the feasibility of a heat-exchange membrane reactor for steam reforming of methane coupled with selective oxidation of permeated hydrogen. The reforming catalyst used was a prereduced nickel based catalyst supported on γ-Al2O3. Hydrogen produced via the steam reforming of methane or water gas shift reaction was able to diffuse through the catalyst bed and transport through the membrane. The permeated hydrogen reacted with oxygen (from air) to produce heat for the steam reforming of methane on the other side of the membrane. The membrane reactor avoids the use of an expensive air separation unit to produce pure oxygen. The influence of experimental conditions, such as temperature, gas hourly space velocity, and the steam to carbon (S/C) ratio, on the membrane reactor was investigated. SrCe0.75Zr0.20Tm0.05O3-δ showed good chemical stability in steam reforming conditions as X-ray diffraction analysis of the membrane surface exposed to steam-reforming conditions for 425 h showed only minor CeO2 formation. The experimental data demonstrate the feasibility of using a proton conducting ceramic membrane in the heat-exchange membrane reactor for steam reforming of methane coupled with selective oxidation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745715 Exemplaires
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Titre : Intensification of synthesis of cumene hydroperoxide using sonochemical reactors Type de document : texte imprimé Auteurs : Vivek P. Chavan, Auteur ; Parag R. Gogate, Auteur Année de publication : 2012 Article en page(s) : pp. 12433-12438 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor Sonochemical reaction Résumé : Intensification of chemical synthesis is a key research area due to the current constraints before the chemical industry due to competition as well as economics and demand for greener routes of processing. The present work illustrates the use of sonochemical reactors for the intensification of synthesis of cumene hydroperoxide from cumene. Air oxidation of cumene in the presence of cupric oxide powder as a catalyst has been investigated using a conventional approach and different sonochemical reactors such as an ultrasonic bath and a probe sonicator. Optimization of different operating parameters such as stirrer speed, temperature, catalyst quantity, air flow rate, and cumene hydroperoxide as an initiator have been investigated using conventional stirring method. The optimum conditions for the air oxidation of the cumene process have been obtained as stirrer speed of 300 rpm, temperature as 110 °C, catalyst quantity of 3 g, and air flow rate as 500 mL/min, and cumene hydroperoxide as an initiator had a very marginal effect. In the case of ultrasound assisted synthesis approach, various parameters studied were pulse of ultrasound, power of ultrasound, and frequency of ultrasound. Enhancement in conversion of cumene and reduction in the reaction time was observed in the presence of ultrasound as compared to silent conditions. The selectivity toward cumene hydroperoxide was marginally affected by the use of ultrasonic conditions. The maximum conversion obtained using ultrasound was 67.1% when 40 kHz frequency of ultrasound horn was used in 4 h, while 50.4% conversion was obtained in 8 h of reaction under otherwise similar operating conditions. The obtained selectivity was always greater than 95% for all conditions considered in the work. The present work has clearly revealed that substantial intensification is obtained for the synthesis of cumene hydroperoxide using ultrasound as compared to the conventional approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745716
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12433-12438[article] Intensification of synthesis of cumene hydroperoxide using sonochemical reactors [texte imprimé] / Vivek P. Chavan, Auteur ; Parag R. Gogate, Auteur . - 2012 . - pp. 12433-12438.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12433-12438
Mots-clés : Reactor Sonochemical reaction Résumé : Intensification of chemical synthesis is a key research area due to the current constraints before the chemical industry due to competition as well as economics and demand for greener routes of processing. The present work illustrates the use of sonochemical reactors for the intensification of synthesis of cumene hydroperoxide from cumene. Air oxidation of cumene in the presence of cupric oxide powder as a catalyst has been investigated using a conventional approach and different sonochemical reactors such as an ultrasonic bath and a probe sonicator. Optimization of different operating parameters such as stirrer speed, temperature, catalyst quantity, air flow rate, and cumene hydroperoxide as an initiator have been investigated using conventional stirring method. The optimum conditions for the air oxidation of the cumene process have been obtained as stirrer speed of 300 rpm, temperature as 110 °C, catalyst quantity of 3 g, and air flow rate as 500 mL/min, and cumene hydroperoxide as an initiator had a very marginal effect. In the case of ultrasound assisted synthesis approach, various parameters studied were pulse of ultrasound, power of ultrasound, and frequency of ultrasound. Enhancement in conversion of cumene and reduction in the reaction time was observed in the presence of ultrasound as compared to silent conditions. The selectivity toward cumene hydroperoxide was marginally affected by the use of ultrasonic conditions. The maximum conversion obtained using ultrasound was 67.1% when 40 kHz frequency of ultrasound horn was used in 4 h, while 50.4% conversion was obtained in 8 h of reaction under otherwise similar operating conditions. The obtained selectivity was always greater than 95% for all conditions considered in the work. The present work has clearly revealed that substantial intensification is obtained for the synthesis of cumene hydroperoxide using ultrasound as compared to the conventional approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745716 Exemplaires
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Titre : Liquid phase hydrodechlorination of chlorobenzene over bimetallic supported zirconia catalyst Type de document : texte imprimé Auteurs : Sujata Mallick, Auteur ; Surjyakanta Rana, Auteur ; Kulamani Parida, Auteur Année de publication : 2012 Article en page(s) : pp. 12439-12448 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst Liquid phase Résumé : Mesoporous zirconia was prepared by the surfactant-assisted route, using cetyltrimethylammonium bromide as cationic surfactant. The synthesized zirconia was employed as support for copper and nickel bimetallic catalysts in the hydrodehalogenation reaction of chlorobenzenes and substituted chlorobenzenes at room temperature. The catalysts were characterized by nitrogen adsorption-desorption, X-ray powder diffraction, Fourier-transfer infrared spectroscopy (FTIR), transmittance electron micrograph (TEM), UV-vis diffuse reflectance spectroscopy (UV—vis DRS), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). The nitrogen adsorption—desorption studies revealed that the modified samples retain the mesoporosity. TEM studies showed uniform distribution of metals having 5-10 nm particles size on the support surface. The bimetallic catalyst exhibited a higher H2 chemisorption capacity relative to monometallic catalysts. For catalytic hydrodehalogenation of chlorobenzene, bimetallic catalyst showed 95% conversion with 100% selectivity for benzene as compared to monometallic catalysts, indicative of the synergy effect of copper, nickel supported on zirconia. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745717
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12439-12448[article] Liquid phase hydrodechlorination of chlorobenzene over bimetallic supported zirconia catalyst [texte imprimé] / Sujata Mallick, Auteur ; Surjyakanta Rana, Auteur ; Kulamani Parida, Auteur . - 2012 . - pp. 12439-12448.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12439-12448
Mots-clés : Catalyst Liquid phase Résumé : Mesoporous zirconia was prepared by the surfactant-assisted route, using cetyltrimethylammonium bromide as cationic surfactant. The synthesized zirconia was employed as support for copper and nickel bimetallic catalysts in the hydrodehalogenation reaction of chlorobenzenes and substituted chlorobenzenes at room temperature. The catalysts were characterized by nitrogen adsorption-desorption, X-ray powder diffraction, Fourier-transfer infrared spectroscopy (FTIR), transmittance electron micrograph (TEM), UV-vis diffuse reflectance spectroscopy (UV—vis DRS), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). The nitrogen adsorption—desorption studies revealed that the modified samples retain the mesoporosity. TEM studies showed uniform distribution of metals having 5-10 nm particles size on the support surface. The bimetallic catalyst exhibited a higher H2 chemisorption capacity relative to monometallic catalysts. For catalytic hydrodehalogenation of chlorobenzene, bimetallic catalyst showed 95% conversion with 100% selectivity for benzene as compared to monometallic catalysts, indicative of the synergy effect of copper, nickel supported on zirconia. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745717 Exemplaires
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Titre : Reactive characteristics and adsorption heat of Ni/ZnO–SiO2–Al2O3 adsorbent by reactive adsorption desulfurization Type de document : texte imprimé Auteurs : Gang Wang, Auteur ; Yaoshun Wen, Auteur ; Jingxin Fan, Auteur Année de publication : 2012 Article en page(s) : pp. 12449-12459 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Desulfurization Adsorption Résumé : Reactive adsorption desulfurization (RADS) experiments of fluid catalytic cracking (FCC) gasoline and a model gasoline over an Ni/ZnO–SiO2–Al2O3 adsorbent were carried out in a fixed-fluidized bed reactor at low pressures in an H2 atmosphere. The results show that hydrogenation, hydrogen transfer, and polymerization reactions accompany RADS. Sulfidation and carbon deposits, which can lead to decreases in the regeneration rate and amount of activated Ni, are crucial to the decay of desulfurization and the olefin-hydrogenation capability of the adsorbents. The obvious reduction of C5 and C6 olefins in FCC gasoline mainly contribute to the drop in octane number of the desulfurization product. The desulfurization experiment on model gasoline and the adsorption heats of model compounds show that RADS removes sulfur from sulfur-containing compound through S–M interactions rather than by π-complexation over the Ni/ZnO–SiO2–Al2O3 adsorbent. The adsorption heat of sulfur-containing compound is proportional to the electron density of sulfur atoms. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745718
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12449-12459[article] Reactive characteristics and adsorption heat of Ni/ZnO–SiO2–Al2O3 adsorbent by reactive adsorption desulfurization [texte imprimé] / Gang Wang, Auteur ; Yaoshun Wen, Auteur ; Jingxin Fan, Auteur . - 2012 . - pp. 12449-12459.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12449-12459
Mots-clés : Desulfurization Adsorption Résumé : Reactive adsorption desulfurization (RADS) experiments of fluid catalytic cracking (FCC) gasoline and a model gasoline over an Ni/ZnO–SiO2–Al2O3 adsorbent were carried out in a fixed-fluidized bed reactor at low pressures in an H2 atmosphere. The results show that hydrogenation, hydrogen transfer, and polymerization reactions accompany RADS. Sulfidation and carbon deposits, which can lead to decreases in the regeneration rate and amount of activated Ni, are crucial to the decay of desulfurization and the olefin-hydrogenation capability of the adsorbents. The obvious reduction of C5 and C6 olefins in FCC gasoline mainly contribute to the drop in octane number of the desulfurization product. The desulfurization experiment on model gasoline and the adsorption heats of model compounds show that RADS removes sulfur from sulfur-containing compound through S–M interactions rather than by π-complexation over the Ni/ZnO–SiO2–Al2O3 adsorbent. The adsorption heat of sulfur-containing compound is proportional to the electron density of sulfur atoms. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745718 Exemplaires
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Titre : Reaction and deactivation rates of methane catalytic cracking over nickel Type de document : texte imprimé Auteurs : Ashraf Amin, Auteur ; William Epling, Auteur ; Eric Croiset, Auteur Année de publication : 2012 Article en page(s) : pp. 12460-12470 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalytic cracking Deactivation Résumé : The kinetics of methane catalytic cracking over nickel supported on porous and nonporous aluminas was modeled using a separable kinetics approach in order to develop initial rate and activity decay equations. The model parameters were estimated using a set of experiments conducted in an electrobalance. The experimental work covered the 500-650 °C temperature range, using pure methane, as well as different partial pressures of CH4/N2 and CH4/H2 mixtures at atmospheric pressure. The model results showed a good match with the experimental data, and the estimated kinetic parameters agreed well with those reported in the literature. The morphology of the support affected the initial reaction rate and catalyst deactivation. The methane cracking activation energy was estimated to be 88 and 75 kj/mol for the porous and nonporous catalysts, respectively. The activation energy for the encapsulating carbon formation was estimated to be 147 and 149 kj/mol for the porous and nonporous catalysts, respectively. The deactivation reaction was found to be half-order in surface carbon. The model was expanded to include cracking/ regeneration cycles. The model showed good agreement with the experimental data at different experimental conditions and up to 39 cycles. Cracking/regeneration cycles suggest that the porous catalyst can be used for conducting continuous methane cracking. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745719
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12460-12470[article] Reaction and deactivation rates of methane catalytic cracking over nickel [texte imprimé] / Ashraf Amin, Auteur ; William Epling, Auteur ; Eric Croiset, Auteur . - 2012 . - pp. 12460-12470.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12460-12470
Mots-clés : Catalytic cracking Deactivation Résumé : The kinetics of methane catalytic cracking over nickel supported on porous and nonporous aluminas was modeled using a separable kinetics approach in order to develop initial rate and activity decay equations. The model parameters were estimated using a set of experiments conducted in an electrobalance. The experimental work covered the 500-650 °C temperature range, using pure methane, as well as different partial pressures of CH4/N2 and CH4/H2 mixtures at atmospheric pressure. The model results showed a good match with the experimental data, and the estimated kinetic parameters agreed well with those reported in the literature. The morphology of the support affected the initial reaction rate and catalyst deactivation. The methane cracking activation energy was estimated to be 88 and 75 kj/mol for the porous and nonporous catalysts, respectively. The activation energy for the encapsulating carbon formation was estimated to be 147 and 149 kj/mol for the porous and nonporous catalysts, respectively. The deactivation reaction was found to be half-order in surface carbon. The model was expanded to include cracking/ regeneration cycles. The model showed good agreement with the experimental data at different experimental conditions and up to 39 cycles. Cracking/regeneration cycles suggest that the porous catalyst can be used for conducting continuous methane cracking. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745719 Exemplaires
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Titre : Mechanistic modeling of hydrolysis and esterification for biofuel processes Type de document : texte imprimé Auteurs : Shujauddin Changi, Auteur ; Tanawan Pinnarat, Auteur ; Phillip E. Savage, Auteur Année de publication : 2012 Article en page(s) : pp. 12471-12478 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Esterification Hydrolysis Modeling Résumé : We have elucidated the mechanism for ethyl oleate hydrolysis in high temperature water and its reverse reaction, oleic acid esterification in near- and supercritical ethanol in the absence of any other added compounds. Both reactions are acid catalyzed. H+ (from dissociation of water and oleic acid) and oleic acid serve as catalysts for hydrolysis and H+ alone is the catalyst for esterification. The rate equation arising from the proposed mechanism provided a good fit of experimental conversion data for both hydrolysis and esterification. The rate equation accurately predicted the influence of pH on hydrolysis for acidic and near-neutral conditions. The mechanistic model exhibits the ability to make quantitatively accurate predictions within and outside the original parameter space, especially for a multicomponent system. Sensitivity analysis shows that the values of the dissociation constant of oleic acid in ethanol, water, and ethanol-water systems strongly influence the predicted conversions. There is a need for experimental measurement of pKa for fatty acids in both water and alcohols at elevated temperatures. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745720
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12471-12478[article] Mechanistic modeling of hydrolysis and esterification for biofuel processes [texte imprimé] / Shujauddin Changi, Auteur ; Tanawan Pinnarat, Auteur ; Phillip E. Savage, Auteur . - 2012 . - pp. 12471-12478.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12471-12478
Mots-clés : Esterification Hydrolysis Modeling Résumé : We have elucidated the mechanism for ethyl oleate hydrolysis in high temperature water and its reverse reaction, oleic acid esterification in near- and supercritical ethanol in the absence of any other added compounds. Both reactions are acid catalyzed. H+ (from dissociation of water and oleic acid) and oleic acid serve as catalysts for hydrolysis and H+ alone is the catalyst for esterification. The rate equation arising from the proposed mechanism provided a good fit of experimental conversion data for both hydrolysis and esterification. The rate equation accurately predicted the influence of pH on hydrolysis for acidic and near-neutral conditions. The mechanistic model exhibits the ability to make quantitatively accurate predictions within and outside the original parameter space, especially for a multicomponent system. Sensitivity analysis shows that the values of the dissociation constant of oleic acid in ethanol, water, and ethanol-water systems strongly influence the predicted conversions. There is a need for experimental measurement of pKa for fatty acids in both water and alcohols at elevated temperatures. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745720 Exemplaires
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Titre : Advanced oxidation of trace organics in water by hydrogen peroxide solar photolysis Type de document : texte imprimé Auteurs : Mario R. Rojas, Auteur ; Cary Leung, Auteur ; Daniel Whitley, Auteur Année de publication : 2012 Article en page(s) : pp. 12479–12487 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxidation Solar photolysis Résumé : Solar-UV/H2O2 advanced oxidation for destruction of trace organics was investigated under a variety of operating conditions in homogeneous, laboratory-scale batch reactor experiments. Fluorescein and p-cresol were selected as representative targets in the experiments. Half times for degradation of p-cresol ranged between 500 min with 2 mM H2O2 and 20 min with 50 mM H2O2 during high-solar irradiance experiments (around noon on July 15th). A kinetic model, previously developed for monochromatic light, was adapted for use with solar UV irradiance, using (i) calculated ground-level solar spectral irradiance for the date and time of the experiments and (ii) wavelength-dependent light attenuation in the reaction mixture. The model accurately represents experimental data without adjustable parameters. Model output included the time-dependent pH arising from complete mineralization of the targets. Observed radical scavenging effects were correctly predicted by the kinetic model. Contaminant transformation was also measured in a municipal secondary wastewater effluent matrix. Here, 2-D fluorescence spectroscopy was used as a measure of the time-dependent bulk organic characteristics in treated wastewater. Results indicated that solar-UV/H2O2 advanced oxidation is capable of eliminating or drastically reducing the concentrations of organic constituents that remain in conventionally treated municipal wastewater effluent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201381j
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12479–12487[article] Advanced oxidation of trace organics in water by hydrogen peroxide solar photolysis [texte imprimé] / Mario R. Rojas, Auteur ; Cary Leung, Auteur ; Daniel Whitley, Auteur . - 2012 . - pp. 12479–12487.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12479–12487
Mots-clés : Oxidation Solar photolysis Résumé : Solar-UV/H2O2 advanced oxidation for destruction of trace organics was investigated under a variety of operating conditions in homogeneous, laboratory-scale batch reactor experiments. Fluorescein and p-cresol were selected as representative targets in the experiments. Half times for degradation of p-cresol ranged between 500 min with 2 mM H2O2 and 20 min with 50 mM H2O2 during high-solar irradiance experiments (around noon on July 15th). A kinetic model, previously developed for monochromatic light, was adapted for use with solar UV irradiance, using (i) calculated ground-level solar spectral irradiance for the date and time of the experiments and (ii) wavelength-dependent light attenuation in the reaction mixture. The model accurately represents experimental data without adjustable parameters. Model output included the time-dependent pH arising from complete mineralization of the targets. Observed radical scavenging effects were correctly predicted by the kinetic model. Contaminant transformation was also measured in a municipal secondary wastewater effluent matrix. Here, 2-D fluorescence spectroscopy was used as a measure of the time-dependent bulk organic characteristics in treated wastewater. Results indicated that solar-UV/H2O2 advanced oxidation is capable of eliminating or drastically reducing the concentrations of organic constituents that remain in conventionally treated municipal wastewater effluent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201381j Exemplaires
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Titre : Neural network analysis of selective CO oxidation over copper - based catalysts for knowledge extraction from published data in the literature Type de document : texte imprimé Auteurs : M. Erdem Gunay, Auteur ; Ramazan Yildirim, Auteur Année de publication : 2012 Article en page(s) : pp. 12488-12500 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst Oxidation Neural network Résumé : In this work, a database containing 1337 data points for selective CO oxidation over Cu-based catalysts was constructed from 20 research publications and used for knowledge extraction by artificial neural networks. The experimental CO conversions reported in each publication were successfully predicted by a neural network trained using the data from the remaining 19 publications unless that one publication contained unique variables. The effects and relative significances of the catalyst preparation variables (such as Cu loading, second metal additive, support type, and preparation method) and operating variables (such as reaction temperature, feed composition, and feed flow rate/catalyst weight ratio) were also determined quite successfully by the artificial neural networks. We conclude that neural network modeling can be used to extract valuable experience and knowledge accumulated in the published data and can help researchers to plan new experiments in a more effective manner. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745722
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12488-12500[article] Neural network analysis of selective CO oxidation over copper - based catalysts for knowledge extraction from published data in the literature [texte imprimé] / M. Erdem Gunay, Auteur ; Ramazan Yildirim, Auteur . - 2012 . - pp. 12488-12500.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12488-12500
Mots-clés : Catalyst Oxidation Neural network Résumé : In this work, a database containing 1337 data points for selective CO oxidation over Cu-based catalysts was constructed from 20 research publications and used for knowledge extraction by artificial neural networks. The experimental CO conversions reported in each publication were successfully predicted by a neural network trained using the data from the remaining 19 publications unless that one publication contained unique variables. The effects and relative significances of the catalyst preparation variables (such as Cu loading, second metal additive, support type, and preparation method) and operating variables (such as reaction temperature, feed composition, and feed flow rate/catalyst weight ratio) were also determined quite successfully by the artificial neural networks. We conclude that neural network modeling can be used to extract valuable experience and knowledge accumulated in the published data and can help researchers to plan new experiments in a more effective manner. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745722 Exemplaires
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Titre : Upgrading residue by carbon rejection in a fluidized - bed reactor and its multiple lump kinetic model Type de document : texte imprimé Auteurs : Hong-liang Wang, Auteur ; Gang Wang, Auteur ; Bao-jian Shen, Auteur Année de publication : 2012 Article en page(s) : pp. 12488-12500 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst Oxidation Neural network Résumé : In this work, a database containing 1337 data points for selective CO oxidation over Cu-based catalysts was constructed from 20 research publications and used for knowledge extraction by artificial neural networks. The experimental CO conversions reported in each publication were successfully predicted by a neural network trained using the data from the remaining 19 publications unless that one publication contained unique variables. The effects and relative significances of the catalyst preparation variables (such as Cu loading, second metal additive, support type, and preparation method) and operating variables (such as reaction temperature, feed composition, and feed flow rate/catalyst weight ratio) were also determined quite successfully by the artificial neural networks. We conclude that neural network modeling can be used to extract valuable experience and knowledge accumulated in the published data and can help researchers to plan new experiments in a more effective manner. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745722
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12488-12500[article] Upgrading residue by carbon rejection in a fluidized - bed reactor and its multiple lump kinetic model [texte imprimé] / Hong-liang Wang, Auteur ; Gang Wang, Auteur ; Bao-jian Shen, Auteur . - 2012 . - pp. 12488-12500.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12488-12500
Mots-clés : Catalyst Oxidation Neural network Résumé : In this work, a database containing 1337 data points for selective CO oxidation over Cu-based catalysts was constructed from 20 research publications and used for knowledge extraction by artificial neural networks. The experimental CO conversions reported in each publication were successfully predicted by a neural network trained using the data from the remaining 19 publications unless that one publication contained unique variables. The effects and relative significances of the catalyst preparation variables (such as Cu loading, second metal additive, support type, and preparation method) and operating variables (such as reaction temperature, feed composition, and feed flow rate/catalyst weight ratio) were also determined quite successfully by the artificial neural networks. We conclude that neural network modeling can be used to extract valuable experience and knowledge accumulated in the published data and can help researchers to plan new experiments in a more effective manner. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745722 Exemplaires
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Titre : Simulation of real wastewater supercritical water oxidation at high concentration on a pilot plant scale Type de document : texte imprimé Auteurs : Violeta Vadillo, Auteur ; M. Belén Garcia-Jarana, Auteur ; Jezabel Sanchez-Oneto, Auteur Année de publication : 2012 Article en page(s) : pp. 12512–12520 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxidation Wastewater Résumé : Supercritical water oxidation (SCWO) has been studied for the past three decades and is now a well-known process. However, the commercial development of this technique is currently delayed due to several drawbacks such as corrosion, salt precipitation, and high costs. In an effort to overcome these constraints several authors have studied and designed new SCWO reactor concepts, but these technical solutions involve the use of special materials and complex designs that increase the process costs. However, conventional SCWO could be commercialized for certain wastewaters that satisfy certain requirements, e.g., very low salt and chloride contents, and it is necessary to continue studying the SCWO process at high concentrations and on the pilot plant scale. At present, simulations based on the SCWO of real wastewaters at high concentrations on the pilot plant scale are scarce in the literature. Process simulation is a powerful tool to study processes in depth and to make advances in the scale-up process. Nevertheless, the use of specific chemical engineering software, such as Prosim Plus or Aspen Plus, is not applicable to simulate a complex wastewater. In addition, the use of the kinetic data available in the literature is not straightforward because these kinetic parameters were obtained from experiments conducted under very different conditions (isothermal, low concentration, etc.). In the work described here, the simulation of Biocut 35 cutting fluid SCWO on a pilot plant scale has been conducted satisfactorily. The model was developed using a Microsoft Excel spreadsheet and a kinetic model obtained on the laboratory scale. Fifteen experiments were carried out in order to validate the simulator. These experiments were conducted on a pilot plant scale at a constant pressure of 250 bar and initial temperatures ranging from 388 to 428 °C. The cutting fluid concentration used in these experiments was varied from 19 to 95 g of O2/L. Finally, the simulator was used to check the effect of the operational variables such as wastewater concentration, initial temperature, wastewater flow rate, and thermal insulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201625y
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12512–12520[article] Simulation of real wastewater supercritical water oxidation at high concentration on a pilot plant scale [texte imprimé] / Violeta Vadillo, Auteur ; M. Belén Garcia-Jarana, Auteur ; Jezabel Sanchez-Oneto, Auteur . - 2012 . - pp. 12512–12520.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12512–12520
Mots-clés : Oxidation Wastewater Résumé : Supercritical water oxidation (SCWO) has been studied for the past three decades and is now a well-known process. However, the commercial development of this technique is currently delayed due to several drawbacks such as corrosion, salt precipitation, and high costs. In an effort to overcome these constraints several authors have studied and designed new SCWO reactor concepts, but these technical solutions involve the use of special materials and complex designs that increase the process costs. However, conventional SCWO could be commercialized for certain wastewaters that satisfy certain requirements, e.g., very low salt and chloride contents, and it is necessary to continue studying the SCWO process at high concentrations and on the pilot plant scale. At present, simulations based on the SCWO of real wastewaters at high concentrations on the pilot plant scale are scarce in the literature. Process simulation is a powerful tool to study processes in depth and to make advances in the scale-up process. Nevertheless, the use of specific chemical engineering software, such as Prosim Plus or Aspen Plus, is not applicable to simulate a complex wastewater. In addition, the use of the kinetic data available in the literature is not straightforward because these kinetic parameters were obtained from experiments conducted under very different conditions (isothermal, low concentration, etc.). In the work described here, the simulation of Biocut 35 cutting fluid SCWO on a pilot plant scale has been conducted satisfactorily. The model was developed using a Microsoft Excel spreadsheet and a kinetic model obtained on the laboratory scale. Fifteen experiments were carried out in order to validate the simulator. These experiments were conducted on a pilot plant scale at a constant pressure of 250 bar and initial temperatures ranging from 388 to 428 °C. The cutting fluid concentration used in these experiments was varied from 19 to 95 g of O2/L. Finally, the simulator was used to check the effect of the operational variables such as wastewater concentration, initial temperature, wastewater flow rate, and thermal insulation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201625y Exemplaires
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Titre : Maize phytoliths and photoluminescent silica nanotubes prepared from a natural silica resource Type de document : texte imprimé Auteurs : Congyun Zhang, Auteur ; Haitao Kang, Auteur ; Kai Lv, Auteur Année de publication : 2012 Article en page(s) : pp. 12521-12526 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Maize Nanotubes Natural silica Résumé : Maize leaves and sheaths are cheap agricultural byproducts that contain an abundance of amorphous hydrated silica (named phytoliths). However, there have been no attempts at utilizing the phytoliths to synthesize silica nanotubes. In this paper, we describe the morphologies and microstructures of phytoliths in leaves and sheaths of maize, and synthesize hollow silica nanotubes using the phytoliths in cetyltrimethyl ammonium bromide (CTAB) /sodium dodecyl benzene sulfonate (SDBS) surfactant system. TEM and SEM images show that the phytoliths exist in cross and dumbbell shapes in maize. The silica nanotubes obtained from the naturally deposited phytoliths exhibit special blue photoluminescence. This optical characteristic indicates that the agro-based waste materials may have potential applications in the fields of light localization and other integrated optical devices. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003768
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12521-12526[article] Maize phytoliths and photoluminescent silica nanotubes prepared from a natural silica resource [texte imprimé] / Congyun Zhang, Auteur ; Haitao Kang, Auteur ; Kai Lv, Auteur . - 2012 . - pp. 12521-12526.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12521-12526
Mots-clés : Maize Nanotubes Natural silica Résumé : Maize leaves and sheaths are cheap agricultural byproducts that contain an abundance of amorphous hydrated silica (named phytoliths). However, there have been no attempts at utilizing the phytoliths to synthesize silica nanotubes. In this paper, we describe the morphologies and microstructures of phytoliths in leaves and sheaths of maize, and synthesize hollow silica nanotubes using the phytoliths in cetyltrimethyl ammonium bromide (CTAB) /sodium dodecyl benzene sulfonate (SDBS) surfactant system. TEM and SEM images show that the phytoliths exist in cross and dumbbell shapes in maize. The silica nanotubes obtained from the naturally deposited phytoliths exhibit special blue photoluminescence. This optical characteristic indicates that the agro-based waste materials may have potential applications in the fields of light localization and other integrated optical devices. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003768 Exemplaires
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Titre : Development of poly(Ether Ether Ketone) (Peek) with inorganic filler for direct methanol fuel cells (DMFCS) Type de document : texte imprimé Auteurs : Jitrada Auimviriyavat, Auteur ; Sairung Changkhamchom, Auteur ; Anuvat Sirivat, Auteur Année de publication : 2012 Article en page(s) : pp. 12527-12533 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fuel cell Filler Résumé : Poly(ether ether ketone) (PEEK) is an organic polymer with excellent thermal stability, chemical resistance, and mechanical properties, that are retained at high temperature. In this study, PEEK was sulfonated with concentrated sulfuric acid (98%) at various degrees of sulfonation (DS) using sulfonation times between 2 and 5 h at a constant temperature of 50 °C. The properties and chemical structure of the sulfonated membranes (S-PEEK) were investigated using TGA, XRD, and FT-IR. In this study, the methanol permeability, thermal and mechanical properties, and proton conductivity of composite membranes were measured for the effect of Ferrierite zeolite as inorganic filler at various amounts (5,10,15,17, and 20% v/v). The proton conductivity and methanol permeability values of the composite membranes were measured compared to those of a commercial membrane, Nafion 117. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745726
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12527-12533[article] Development of poly(Ether Ether Ketone) (Peek) with inorganic filler for direct methanol fuel cells (DMFCS) [texte imprimé] / Jitrada Auimviriyavat, Auteur ; Sairung Changkhamchom, Auteur ; Anuvat Sirivat, Auteur . - 2012 . - pp. 12527-12533.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12527-12533
Mots-clés : Fuel cell Filler Résumé : Poly(ether ether ketone) (PEEK) is an organic polymer with excellent thermal stability, chemical resistance, and mechanical properties, that are retained at high temperature. In this study, PEEK was sulfonated with concentrated sulfuric acid (98%) at various degrees of sulfonation (DS) using sulfonation times between 2 and 5 h at a constant temperature of 50 °C. The properties and chemical structure of the sulfonated membranes (S-PEEK) were investigated using TGA, XRD, and FT-IR. In this study, the methanol permeability, thermal and mechanical properties, and proton conductivity of composite membranes were measured for the effect of Ferrierite zeolite as inorganic filler at various amounts (5,10,15,17, and 20% v/v). The proton conductivity and methanol permeability values of the composite membranes were measured compared to those of a commercial membrane, Nafion 117. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745726 Exemplaires
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Titre : Role of inorganic and organic medium in the corrosion behavior of bacillus megaterium and pseudomonas sp. in stainless steel SS 304 Type de document : texte imprimé Auteurs : Aruliah Rajasekar, Auteur ; Yen-Peng Ting, Auteur Année de publication : 2012 Article en page(s) : pp. 12534-12541 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Bacteria Pseudomonadales Pseudomonadaceae Stainless steel Pseudomonas Corrosion Résumé : The production of extracellular polysaccharides (EPS) forms a layer on a metal surface that may either inhibit or accelerate corrosion. In the present study, the biocorrosion behavior of stainless steel 304 in the presence of aerobic bacteria Bacillus megaterium and Pseudomonas sp. was investigated in different growth media; an inorganic medium and an organic medium with 3.5% sodium chloride as the electrolyte. Biocorrosion was evaluated using potentiodynamic anodic and cathodic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy-energy dispersive spectrum analysis (SEM-EDAX), and Fourier transform infrared spectroscopy (FTIR). The corrosion potential (Ecorr) and pitting potential (Epit) were lower in the presence of both bacteria in the inorganic medium when compared to the organic medium. The inorganic medium consisted of inorganic nitrates and phosphates which accelerated the production of bacterial metabolites and enhanced corrosion resistance through the formation of a passive layer which inhibited the corrosion. Exposure of the metal in organic medium however caused both bacteria to shift the corrosion potential (Ecorr) toward the negative direction, thus causing the metal to undergo severe pitting attack. Electrochemical measurements showed that both the bacteria enhanced pitting corrosion in the organic medium. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745727
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12534-12541[article] Role of inorganic and organic medium in the corrosion behavior of bacillus megaterium and pseudomonas sp. in stainless steel SS 304 [texte imprimé] / Aruliah Rajasekar, Auteur ; Yen-Peng Ting, Auteur . - 2012 . - pp. 12534-12541.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12534-12541
Mots-clés : Bacteria Pseudomonadales Pseudomonadaceae Stainless steel Pseudomonas Corrosion Résumé : The production of extracellular polysaccharides (EPS) forms a layer on a metal surface that may either inhibit or accelerate corrosion. In the present study, the biocorrosion behavior of stainless steel 304 in the presence of aerobic bacteria Bacillus megaterium and Pseudomonas sp. was investigated in different growth media; an inorganic medium and an organic medium with 3.5% sodium chloride as the electrolyte. Biocorrosion was evaluated using potentiodynamic anodic and cathodic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy-energy dispersive spectrum analysis (SEM-EDAX), and Fourier transform infrared spectroscopy (FTIR). The corrosion potential (Ecorr) and pitting potential (Epit) were lower in the presence of both bacteria in the inorganic medium when compared to the organic medium. The inorganic medium consisted of inorganic nitrates and phosphates which accelerated the production of bacterial metabolites and enhanced corrosion resistance through the formation of a passive layer which inhibited the corrosion. Exposure of the metal in organic medium however caused both bacteria to shift the corrosion potential (Ecorr) toward the negative direction, thus causing the metal to undergo severe pitting attack. Electrochemical measurements showed that both the bacteria enhanced pitting corrosion in the organic medium. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745727 Exemplaires
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Titre : Morphological evolution from SnO2 quantum dots to quantum chains inside channels of mesoporous spheres Type de document : texte imprimé Auteurs : Feng Gu, Auteur ; Xiang Ren, Auteur ; Jian Zhang, Auteur Année de publication : 2012 Article en page(s) : pp. 12542-12547 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Morphological quantum Mesoporous Résumé : Morphological evolution from SnO2 quantum dots (QDs) to quantum chains (QCs) confined in channels of mesoporous silica (MS) has been studied systematically in this work by varying the nuclei quantity deposited on the channels’ inner surface under hydrothermal conditions. Decreasing the MS amounts could influence the nuclei quantity and the subsequent crystal growth as well as the assembly process to form QCs by oriented attachment inside the channels. It is interesting to find that the evolution of SnO2 QDs→QCs systems would induce the variation of strain type tolerated, simultaneously, from tensile to compressive strain, and also exhibit morphology-dependent photoluminescence properties. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201152e
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12542-12547[article] Morphological evolution from SnO2 quantum dots to quantum chains inside channels of mesoporous spheres [texte imprimé] / Feng Gu, Auteur ; Xiang Ren, Auteur ; Jian Zhang, Auteur . - 2012 . - pp. 12542-12547.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12542-12547
Mots-clés : Morphological quantum Mesoporous Résumé : Morphological evolution from SnO2 quantum dots (QDs) to quantum chains (QCs) confined in channels of mesoporous silica (MS) has been studied systematically in this work by varying the nuclei quantity deposited on the channels’ inner surface under hydrothermal conditions. Decreasing the MS amounts could influence the nuclei quantity and the subsequent crystal growth as well as the assembly process to form QCs by oriented attachment inside the channels. It is interesting to find that the evolution of SnO2 QDs→QCs systems would induce the variation of strain type tolerated, simultaneously, from tensile to compressive strain, and also exhibit morphology-dependent photoluminescence properties. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201152e Exemplaires
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Titre : Effect of organoclay reinforcement on lignin - based carbon fibers Type de document : texte imprimé Auteurs : W. Qin, Auteur ; J. F. Kadla, Auteur Année de publication : 2012 Article en page(s) : pp 12548–12555 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon fiber Résumé : Organoclay reinforced carbon fibers were prepared from pyrolytic lignin isolated from a commercial bio-oil. Organoclay reinforcement improved the tensile strength of the pyrolytic lignin based carbon fibers by 12% at clay loadings below 2 wt %. Wide-angle X-ray diffraction analysis of the composite as-spun fibers revealed the successful intercalation of the organoclays (Cloisite 20A and 30B), which helped develop a more ordered structure after carbonization. However, only the 1.0 wt % Cloisite 30B as-spun fibers showed an increase in Young's modulus, while all other as-spun fibers remained unchanged. By contrast, all of the carbon fibers showed a drop in young's modulus (by 16-38%) upon addition of organoclay, decreasing as organoclay content increased. This is likely due to the presence of microvoids in the carbon fiber as well as the lack of preferred orientation of clay platelets along the fiber axis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745729
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp 12548–12555[article] Effect of organoclay reinforcement on lignin - based carbon fibers [texte imprimé] / W. Qin, Auteur ; J. F. Kadla, Auteur . - 2012 . - pp 12548–12555.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp 12548–12555
Mots-clés : Carbon fiber Résumé : Organoclay reinforced carbon fibers were prepared from pyrolytic lignin isolated from a commercial bio-oil. Organoclay reinforcement improved the tensile strength of the pyrolytic lignin based carbon fibers by 12% at clay loadings below 2 wt %. Wide-angle X-ray diffraction analysis of the composite as-spun fibers revealed the successful intercalation of the organoclays (Cloisite 20A and 30B), which helped develop a more ordered structure after carbonization. However, only the 1.0 wt % Cloisite 30B as-spun fibers showed an increase in Young's modulus, while all other as-spun fibers remained unchanged. By contrast, all of the carbon fibers showed a drop in young's modulus (by 16-38%) upon addition of organoclay, decreasing as organoclay content increased. This is likely due to the presence of microvoids in the carbon fiber as well as the lack of preferred orientation of clay platelets along the fiber axis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745729 Exemplaires
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Titre : Amphiphilic interpenetrating networks for the delivery of hydrophobic, low molecular weight therapeutic agents Type de document : texte imprimé Auteurs : Cody A. Schoener, Auteur ; Heather N. Hutson, Auteur ; Grace K. Fletcher, Auteur Année de publication : 2012 Article en page(s) : pp. 12556–12561 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrophobic Résumé : To investigate the delivery of hydrophobic therapeutic agents, a novel class of interpenetrating networks (IPNs) was synthesized and composed of two networks: methacrylic acid grafted with poly(ethylene glycol) tethers, P(MAA-g-EG) and poly(n-butyl acrylate) (PBA). The hydrophilic P(MAA-g-EG) networks are pH-responsive hydrogels capable of triggered release of an encapsulated therapeutic agent, such as a low molecular weight drug or a protein, when it passes from the stomach (low pH) to the upper small intestine (neutral pH). PBA is a hydrophobic homopolymer that can affect the IPN swelling behavior, the therapeutic agent loading efficiencies in IPNs, and solute release profiles from IPNs. In dynamic swelling conditions, IPNs had greater swelling ratios than P(MAA-g-EG), but in equilibrium swelling conditions the IPN swelling ratio decreased with increasing PBA content. Loading efficiencies of the model therapeutic agent fluorescein ranged from 21–44%. Release studies from neat P(MAA-g-EG) and the ensuing IPNs indicated that the transition from low pH (2.0) to neutral pH (7.0) triggered fluorescein release. Maximum fluorescein release depended on the structure and hydrophilicity of the carriers used in these studies. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201593h
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12556–12561[article] Amphiphilic interpenetrating networks for the delivery of hydrophobic, low molecular weight therapeutic agents [texte imprimé] / Cody A. Schoener, Auteur ; Heather N. Hutson, Auteur ; Grace K. Fletcher, Auteur . - 2012 . - pp. 12556–12561.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12556–12561
Mots-clés : Hydrophobic Résumé : To investigate the delivery of hydrophobic therapeutic agents, a novel class of interpenetrating networks (IPNs) was synthesized and composed of two networks: methacrylic acid grafted with poly(ethylene glycol) tethers, P(MAA-g-EG) and poly(n-butyl acrylate) (PBA). The hydrophilic P(MAA-g-EG) networks are pH-responsive hydrogels capable of triggered release of an encapsulated therapeutic agent, such as a low molecular weight drug or a protein, when it passes from the stomach (low pH) to the upper small intestine (neutral pH). PBA is a hydrophobic homopolymer that can affect the IPN swelling behavior, the therapeutic agent loading efficiencies in IPNs, and solute release profiles from IPNs. In dynamic swelling conditions, IPNs had greater swelling ratios than P(MAA-g-EG), but in equilibrium swelling conditions the IPN swelling ratio decreased with increasing PBA content. Loading efficiencies of the model therapeutic agent fluorescein ranged from 21–44%. Release studies from neat P(MAA-g-EG) and the ensuing IPNs indicated that the transition from low pH (2.0) to neutral pH (7.0) triggered fluorescein release. Maximum fluorescein release depended on the structure and hydrophilicity of the carriers used in these studies. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201593h Exemplaires
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Titre : Polypyrrole coated thermally exfoliated graphite nanoplatelets and the effect of oxygen surface groups on the interaction of platinum catalysts with graphene - based nanocomposites Type de document : texte imprimé Auteurs : Burcu Saner Okan, Auteur ; Alp Yurum, Auteur ; Neylan Gorgulu, Auteur Année de publication : 2012 Article en page(s) : pp. 12562–12571 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalysts Nanocomposites Résumé : Expanded graphite oxide (GO) synthesized by graphite oxidation and thermal expansion was exposed to ultrasonic vibration to obtain graphite nanoplatelets (GNFs). Then, expanded GO as conductive filler was dispersed in polypyrrole matrix in order to be utilized as catalyst support. Electrical conductivities and polymer thickness of GNF-based composites were tailored at different feeding mass ratios. Thermal expansion led to the removal of oxygen functional groups on the surface, and the C/O ratio increased to 6. The highest C/O ratio had less hydrophilic carbon surface, and this decreased the interaction of Pt particles with support. When comparing Pt deposition behavior of GO, expanded GO, graphene nanosheets, and their composites, the results showed that Pt dispersion increased with increasing amount of oxygen functional groups on the surface of the samples. This work was the first comprehensive and quantitative investigation on the relationship between Pt dispersion and surface oxygen functional groups of graphene-based nanocomposites. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201613f
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12562–12571[article] Polypyrrole coated thermally exfoliated graphite nanoplatelets and the effect of oxygen surface groups on the interaction of platinum catalysts with graphene - based nanocomposites [texte imprimé] / Burcu Saner Okan, Auteur ; Alp Yurum, Auteur ; Neylan Gorgulu, Auteur . - 2012 . - pp. 12562–12571.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12562–12571
Mots-clés : Catalysts Nanocomposites Résumé : Expanded graphite oxide (GO) synthesized by graphite oxidation and thermal expansion was exposed to ultrasonic vibration to obtain graphite nanoplatelets (GNFs). Then, expanded GO as conductive filler was dispersed in polypyrrole matrix in order to be utilized as catalyst support. Electrical conductivities and polymer thickness of GNF-based composites were tailored at different feeding mass ratios. Thermal expansion led to the removal of oxygen functional groups on the surface, and the C/O ratio increased to 6. The highest C/O ratio had less hydrophilic carbon surface, and this decreased the interaction of Pt particles with support. When comparing Pt deposition behavior of GO, expanded GO, graphene nanosheets, and their composites, the results showed that Pt dispersion increased with increasing amount of oxygen functional groups on the surface of the samples. This work was the first comprehensive and quantitative investigation on the relationship between Pt dispersion and surface oxygen functional groups of graphene-based nanocomposites. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201613f Exemplaires
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Titre : Fiber quality analysis : op test fiber quality analyzer versus L&W fiber tester Type de document : texte imprimé Auteurs : Bin Li, Auteur ; Rohan Bandekar, Auteur ; Quanqing Zha, Auteur Année de publication : 2012 Article en page(s) : pp. 12572–12578 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fiber quality analyzer Résumé : In this paper, the measurements from OpTest FQA (fiber quality analyzer) and L&W Fiber Tester were compared on 95 TMP (thermomechanical pulp) samples from a TMP-based newsprint mill in Eastern Canada that uses mixed black spruce and balsam fir as raw material. It was found that both FQA and L&W Fiber Tester provide repeatable measurements for fiber length, fines, coarseness, curl, and kink index. However, there were significant differences in the results obtained from the two instruments. Compared to FQA, the L&W Fiber Tester measurements were on average 59% higher for the arithmetic mean fiber length and arithmetic fines content, about 6% higher for the length weighted mean fiber length, approximately 44% lower for the coarseness, and about 37% lower for the kink index. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201631q
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12572–12578[article] Fiber quality analysis : op test fiber quality analyzer versus L&W fiber tester [texte imprimé] / Bin Li, Auteur ; Rohan Bandekar, Auteur ; Quanqing Zha, Auteur . - 2012 . - pp. 12572–12578.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12572–12578
Mots-clés : Fiber quality analyzer Résumé : In this paper, the measurements from OpTest FQA (fiber quality analyzer) and L&W Fiber Tester were compared on 95 TMP (thermomechanical pulp) samples from a TMP-based newsprint mill in Eastern Canada that uses mixed black spruce and balsam fir as raw material. It was found that both FQA and L&W Fiber Tester provide repeatable measurements for fiber length, fines, coarseness, curl, and kink index. However, there were significant differences in the results obtained from the two instruments. Compared to FQA, the L&W Fiber Tester measurements were on average 59% higher for the arithmetic mean fiber length and arithmetic fines content, about 6% higher for the length weighted mean fiber length, approximately 44% lower for the coarseness, and about 37% lower for the kink index. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201631q Exemplaires
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Titre : Isothermal and nonisothermal cold crystallization behaviors of biodegradable poly (l-lactide) / octavinyl - polyhedral oligomeric silsesquioxanes nanocomposites Type de document : texte imprimé Auteurs : Jing Yu, Auteur ; Zhaobin Qiu, Auteur Année de publication : 2012 Article en page(s) : pp. 12579–12586 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Crystallization Biodegradable Nanocomposites Résumé : Isothermal and nonisothermal cold crystallization behaviors of biodegradable poly(l-lactide) (PLLA)/octavinyl-polyhedral oligomeric silsesquioxanes (ovi-POSS) nanocomposites at low ovi-POSS loadings were investigated in this work. For both neat PLLA and its nanocomposites, the overall isothermal cold crystallization rates increase with increasing crystallization temperature; moreover, the overall isothermal cold crystallization rates of PLLA increase with increasing the ovi-POSS loading in the nanocomposites relative to neat PLLA, indicative of the nucleating agent effect of ovi-POSS. Crystallization mechanism and crystal structure of PLLA remain unchanged despite the ovi-POSS loading. For the nonisothermal cold crystallization, the crystallization process of PLLA is accelerated by increasing both heating rate and the ovi-POSS loading. The Ozawa equation failed to fit the crystallization process, while the Tobin equation could describe it well. The activation energies of nonisothermal cold crystallization were calculated by the Kissinger method, which increase with increasing the ovi-POSS loading in the nanocomposites relative to neat PLLA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201691y
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12579–12586[article] Isothermal and nonisothermal cold crystallization behaviors of biodegradable poly (l-lactide) / octavinyl - polyhedral oligomeric silsesquioxanes nanocomposites [texte imprimé] / Jing Yu, Auteur ; Zhaobin Qiu, Auteur . - 2012 . - pp. 12579–12586.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12579–12586
Mots-clés : Crystallization Biodegradable Nanocomposites Résumé : Isothermal and nonisothermal cold crystallization behaviors of biodegradable poly(l-lactide) (PLLA)/octavinyl-polyhedral oligomeric silsesquioxanes (ovi-POSS) nanocomposites at low ovi-POSS loadings were investigated in this work. For both neat PLLA and its nanocomposites, the overall isothermal cold crystallization rates increase with increasing crystallization temperature; moreover, the overall isothermal cold crystallization rates of PLLA increase with increasing the ovi-POSS loading in the nanocomposites relative to neat PLLA, indicative of the nucleating agent effect of ovi-POSS. Crystallization mechanism and crystal structure of PLLA remain unchanged despite the ovi-POSS loading. For the nonisothermal cold crystallization, the crystallization process of PLLA is accelerated by increasing both heating rate and the ovi-POSS loading. The Ozawa equation failed to fit the crystallization process, while the Tobin equation could describe it well. The activation energies of nonisothermal cold crystallization were calculated by the Kissinger method, which increase with increasing the ovi-POSS loading in the nanocomposites relative to neat PLLA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201691y Exemplaires
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Titre : Additive - driven dissolution enhancement of colloidal silica. 1. basic principles and relevance to water treatment Type de document : texte imprimé Auteurs : Konstantinos D. Demadis, Auteur ; Eleftheria Mavredaki, Auteur ; Maria Somara, Auteur Année de publication : 2012 Article en page(s) : pp. 12587-12595 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Water treatment Dissolution Additive Résumé : The effect of various chemical additives (small molecules and polymers) on the dissolution of two kinds of colloidal silica (Aerosil 200 and laboratory-synthesized, SSD) is systematically studied at pH 10. The silica scale dissolvers tested are 5-carbosybenzotriazole (CBZT), amino-tris(methylene phosphonic acid) (AMP), a phosphino-polycarboxylic acid (PPCA), diethylenetriamine pentacarboxylic acid (DETPA), a proprietary polymer (Genesol 40), poly(acrylic acid) (PAA), ethylenediamine-tetrakis(methylenephosphonic acid) (EDTMP), phosphonobutane-1,2,4-tricarbosylic acid (PBTC), sodium metaborate, and N-phosphonomethylimino-diacetic acid (PMIDA). Of the polymeric additives only Genesol 40 shows some dissolution activity, dissolving ~280 ppm silica at 10000 ppm dosage after 72 h. PBTC and DETPA are the best-performing additives of all those tested. PBTC is effective even at the 2500 ppm dosage, as it solubilizes ~290 ppm silica after 72 h. Its efficiency is dosage-dependent. DETPA is also an effective silica dissolver. Its behavior is similar to that of PBTC. Its best dosage is 7500 ppm, which yields dissolution of 322 ppm silica (after 24 h), 340 ppm (after 48 h), and 333 ppm (after 72 h). SSD silica is a very recalcitrant deposit showing resistance to dissolution even by the most effective additives, PBTC and DETPA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745734
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12587-12595[article] Additive - driven dissolution enhancement of colloidal silica. 1. basic principles and relevance to water treatment [texte imprimé] / Konstantinos D. Demadis, Auteur ; Eleftheria Mavredaki, Auteur ; Maria Somara, Auteur . - 2012 . - pp. 12587-12595.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12587-12595
Mots-clés : Water treatment Dissolution Additive Résumé : The effect of various chemical additives (small molecules and polymers) on the dissolution of two kinds of colloidal silica (Aerosil 200 and laboratory-synthesized, SSD) is systematically studied at pH 10. The silica scale dissolvers tested are 5-carbosybenzotriazole (CBZT), amino-tris(methylene phosphonic acid) (AMP), a phosphino-polycarboxylic acid (PPCA), diethylenetriamine pentacarboxylic acid (DETPA), a proprietary polymer (Genesol 40), poly(acrylic acid) (PAA), ethylenediamine-tetrakis(methylenephosphonic acid) (EDTMP), phosphonobutane-1,2,4-tricarbosylic acid (PBTC), sodium metaborate, and N-phosphonomethylimino-diacetic acid (PMIDA). Of the polymeric additives only Genesol 40 shows some dissolution activity, dissolving ~280 ppm silica at 10000 ppm dosage after 72 h. PBTC and DETPA are the best-performing additives of all those tested. PBTC is effective even at the 2500 ppm dosage, as it solubilizes ~290 ppm silica after 72 h. Its efficiency is dosage-dependent. DETPA is also an effective silica dissolver. Its behavior is similar to that of PBTC. Its best dosage is 7500 ppm, which yields dissolution of 322 ppm silica (after 24 h), 340 ppm (after 48 h), and 333 ppm (after 72 h). SSD silica is a very recalcitrant deposit showing resistance to dissolution even by the most effective additives, PBTC and DETPA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745734 Exemplaires
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Titre : Effects of nonsolvent molecular structure and its content on the formation of the macroporous polyarylate layer coated onto the polyethylene separator Type de document : texte imprimé Auteurs : Sang Chul Roh, Auteur ; Kwon Won Song, Auteur ; C. K. Kim, Auteur Année de publication : 2012 Article en page(s) : pp. 12596–12605 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Macroporous Polyethylene Résumé : A macroporous polyarylate (PAR) layer was formed on a polyethylene (PE) separator from coating solutions containing PAR, tetrahydrofuran (THF) as the solvent, and various alcohols (or diols) as nonsolvents via a nonsolvent-induced phase separation (NIPS) process. The effects of the nonsolvent molecular structure and its content on the morphology of the coating layer were explored. Droplets grew by a coarsening process after the onset of phase separation by solvent evaporation, and then leveled off at a fixed droplet size. The final pore size increased with the molecular weight of the alcohol (or diol) when the composition of the coating solution was fixed. It increased as the nonsolvent content in the coating solution increased, while it decreased as the PAR content in the coating solution increased. The meltdown temperature of the separator increased with the macroporous PAR coating, while air permeability of the separator was reduced with the coating. Changes in the meltdown temperature and air permeability depended on the morphology of the coating layer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201716m
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12596–12605[article] Effects of nonsolvent molecular structure and its content on the formation of the macroporous polyarylate layer coated onto the polyethylene separator [texte imprimé] / Sang Chul Roh, Auteur ; Kwon Won Song, Auteur ; C. K. Kim, Auteur . - 2012 . - pp. 12596–12605.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12596–12605
Mots-clés : Macroporous Polyethylene Résumé : A macroporous polyarylate (PAR) layer was formed on a polyethylene (PE) separator from coating solutions containing PAR, tetrahydrofuran (THF) as the solvent, and various alcohols (or diols) as nonsolvents via a nonsolvent-induced phase separation (NIPS) process. The effects of the nonsolvent molecular structure and its content on the morphology of the coating layer were explored. Droplets grew by a coarsening process after the onset of phase separation by solvent evaporation, and then leveled off at a fixed droplet size. The final pore size increased with the molecular weight of the alcohol (or diol) when the composition of the coating solution was fixed. It increased as the nonsolvent content in the coating solution increased, while it decreased as the PAR content in the coating solution increased. The meltdown temperature of the separator increased with the macroporous PAR coating, while air permeability of the separator was reduced with the coating. Changes in the meltdown temperature and air permeability depended on the morphology of the coating layer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201716m Exemplaires
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Titre : Screening metal – organic framework - based mixed - matrix membranes for CO2/CH4 separations Type de document : texte imprimé Auteurs : Ilknur Erucar, Auteur ; Seda Keskin, Auteur Année de publication : 2012 Article en page(s) : pp. 12606-12616 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon dioxide Résumé : In this study, the challenge of selecting metal-organic frameworks (MOFs) as filler particles in high-performance mixed-matrix membranes (MMMs) was examined using atomistic and continuum modeling. We tested several theoretical permeation models, including the Maxwell, modified Maxwell, Bruggeman, Lewis-Nielson, Pal, Felske, and modified Felske models, by comparing the predictions of these models with the experimental data for IRMOF-1/Matrimid and CuBTC/Matrimid MMMs. After identifying the model making the best predictions, we examined the performance of 80 new MOF-based MMMs composed of 10 different MOFs and eight different polymers for CO2/CH4 separations. Our results show that selecting the appropriate MOF as filler particles in polymers can result in MMMs with extraordinarily high CO2 selectivities and CO2 permeabilities relative to those of pure polymer membranes. The methods introduced in this study will create many opportunities for selecting MOF/polymer combinations for MMMs with useful properties for CO2 separation applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745736
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12606-12616[article] Screening metal – organic framework - based mixed - matrix membranes for CO2/CH4 separations [texte imprimé] / Ilknur Erucar, Auteur ; Seda Keskin, Auteur . - 2012 . - pp. 12606-12616.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12606-12616
Mots-clés : Carbon dioxide Résumé : In this study, the challenge of selecting metal-organic frameworks (MOFs) as filler particles in high-performance mixed-matrix membranes (MMMs) was examined using atomistic and continuum modeling. We tested several theoretical permeation models, including the Maxwell, modified Maxwell, Bruggeman, Lewis-Nielson, Pal, Felske, and modified Felske models, by comparing the predictions of these models with the experimental data for IRMOF-1/Matrimid and CuBTC/Matrimid MMMs. After identifying the model making the best predictions, we examined the performance of 80 new MOF-based MMMs composed of 10 different MOFs and eight different polymers for CO2/CH4 separations. Our results show that selecting the appropriate MOF as filler particles in polymers can result in MMMs with extraordinarily high CO2 selectivities and CO2 permeabilities relative to those of pure polymer membranes. The methods introduced in this study will create many opportunities for selecting MOF/polymer combinations for MMMs with useful properties for CO2 separation applications. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745736 Exemplaires
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Titre : Thermodynamic analysis of solid – liquid phase equilibria of nitrate salts Type de document : texte imprimé Auteurs : Scott M. Davison, Auteur ; Amy C. Sun, Auteur Année de publication : 2012 Article en page(s) : pp. 12617–12625 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamic Résumé : In this work, we analyze solid–liquid phase equilibria of molten nitrate salt mixtures. Molten salts are used as heat transfer fluids within concentrated solar power systems. Further understanding of the thermophysical properties of the salt solutions is integral to designing the newest generation of solar power systems. We make use of classical thermodynamics to quickly model the phase equilibrium of mixtures of nitrate salts. This modeling work can serve as a complement to existing experimental efforts in identifying appropriate multicomponent salt mixtures for solar power applications. We present phase calculations of ternary and quaternary mixtures of LiNO3, NaNO3, KNO3, and CsNO3 modeled using the Wilson equation for liquid phase activity coefficients and binary solid–liquid equilibrium data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200581g
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12617–12625[article] Thermodynamic analysis of solid – liquid phase equilibria of nitrate salts [texte imprimé] / Scott M. Davison, Auteur ; Amy C. Sun, Auteur . - 2012 . - pp. 12617–12625.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12617–12625
Mots-clés : Thermodynamic Résumé : In this work, we analyze solid–liquid phase equilibria of molten nitrate salt mixtures. Molten salts are used as heat transfer fluids within concentrated solar power systems. Further understanding of the thermophysical properties of the salt solutions is integral to designing the newest generation of solar power systems. We make use of classical thermodynamics to quickly model the phase equilibrium of mixtures of nitrate salts. This modeling work can serve as a complement to existing experimental efforts in identifying appropriate multicomponent salt mixtures for solar power applications. We present phase calculations of ternary and quaternary mixtures of LiNO3, NaNO3, KNO3, and CsNO3 modeled using the Wilson equation for liquid phase activity coefficients and binary solid–liquid equilibrium data. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200581g Exemplaires
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Titre : Parameter - based model for the forecasting of pipe corrosion in refinery plants Type de document : texte imprimé Auteurs : Seungnam Kim, Auteur ; Junghwan Kim, Auteur ; Il Moon, Auteur Année de publication : 2012 Article en page(s) : pp. 12626-12629 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Refinery Corrosion Modeling Résumé : Corrosion of devices and pipes in refinery and petrochemical plants cause problems like deterioration of process efficiency and equipment reliability etc. Hence, a suitable technology is required to prevent accident caused by corrosion and raise process efficiency by forecasting the degree of corrosion. The corrosion problems on the top of the distillation column are more serious due to corrosive substances like hydrogen sulfide and chlorine etc. Therefore, in this study, corrosion rate was forecasted and applied through analysis of the corrosion mechanism on the top of refinery distillation column and the validity of the model was checked using the actual data.: considering interference effect caused by competitive reactions between caustic substances. The four components that affect corrosion the most, H2S, CO2, H+, and Cl-, were selected through analysis of the mechanism of corrosion on the top of refinery distillation tower. The model for the analysis of corrosion mechanism was analyzed in the viewpoint of transport phenomenon and reaction engineering, and parameters were estimated with the use of least-squares method. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745738
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12626-12629[article] Parameter - based model for the forecasting of pipe corrosion in refinery plants [texte imprimé] / Seungnam Kim, Auteur ; Junghwan Kim, Auteur ; Il Moon, Auteur . - 2012 . - pp. 12626-12629.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12626-12629
Mots-clés : Refinery Corrosion Modeling Résumé : Corrosion of devices and pipes in refinery and petrochemical plants cause problems like deterioration of process efficiency and equipment reliability etc. Hence, a suitable technology is required to prevent accident caused by corrosion and raise process efficiency by forecasting the degree of corrosion. The corrosion problems on the top of the distillation column are more serious due to corrosive substances like hydrogen sulfide and chlorine etc. Therefore, in this study, corrosion rate was forecasted and applied through analysis of the corrosion mechanism on the top of refinery distillation column and the validity of the model was checked using the actual data.: considering interference effect caused by competitive reactions between caustic substances. The four components that affect corrosion the most, H2S, CO2, H+, and Cl-, were selected through analysis of the mechanism of corrosion on the top of refinery distillation tower. The model for the analysis of corrosion mechanism was analyzed in the viewpoint of transport phenomenon and reaction engineering, and parameters were estimated with the use of least-squares method. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745738 Exemplaires
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Titre : Thermodynamic - analysis - based energy consumption minimization for natural gas liquefaction Type de document : texte imprimé Auteurs : Meiqian Wang, Auteur ; Jian Zhang, Auteur ; Qiang Xu, Auteur Année de publication : 2012 Article en page(s) : pp. 12630-12640 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquefaction Natural gas Energy consumption Thermodynamic analysis Résumé : The natural gas liquefaction process is an important sector of the overall liquefied natural gas (LNG) value chain. In this article, a thermodynamic-analysis-based study of the mutimization of the energy consumption of a typical natural gas liquefaction process is performed. First, a rigorous simulation of the natural gas liquefaction process is conducted. According to the simulation results, the operating states of the refrigerant and natural gas streams are revealed, along with the operating conditions of the entire liquefaction process. Then, the energy consumption roadmap is determined through in-depth thermodynamic analysis, where the opportunities for energy consumption minimization are identified. Based on the thermodynamic analysis, a rigorous optimization model is developed and solved for energy consumption reduction of the same natural gas liquefaction process. Finally, the optimization results are examined again through rigorous simulation to check the feasibility of the obtained optimal solution. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745739
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12630-12640[article] Thermodynamic - analysis - based energy consumption minimization for natural gas liquefaction [texte imprimé] / Meiqian Wang, Auteur ; Jian Zhang, Auteur ; Qiang Xu, Auteur . - 2012 . - pp. 12630-12640.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12630-12640
Mots-clés : Liquefaction Natural gas Energy consumption Thermodynamic analysis Résumé : The natural gas liquefaction process is an important sector of the overall liquefied natural gas (LNG) value chain. In this article, a thermodynamic-analysis-based study of the mutimization of the energy consumption of a typical natural gas liquefaction process is performed. First, a rigorous simulation of the natural gas liquefaction process is conducted. According to the simulation results, the operating states of the refrigerant and natural gas streams are revealed, along with the operating conditions of the entire liquefaction process. Then, the energy consumption roadmap is determined through in-depth thermodynamic analysis, where the opportunities for energy consumption minimization are identified. Based on the thermodynamic analysis, a rigorous optimization model is developed and solved for energy consumption reduction of the same natural gas liquefaction process. Finally, the optimization results are examined again through rigorous simulation to check the feasibility of the obtained optimal solution. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745739 Exemplaires
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Titre : Integrated energy optimization model for oil sands operations Type de document : texte imprimé Auteurs : Alberto Betancourt-Torcat, Auteur ; Gloria Gutierrez, Auteur ; Ali Elkamel, Auteur Année de publication : 2012 Article en page(s) : pp. 12641-12663 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Tar sand Modeling Optimization Résumé : This article presents a new energy model that predicts the energy infrastructure required to maintain oil production in the Canadian Oil Sands operation at minimum cost. Previous studies in this area have focused on the energy infrastructure for fixed energy demands (i.e., the production schemes that produce synthetic crude oil (SCO) and commercial diluted bitumen remained fixed in the calculation of the optimal infrastructure). The key novelty of this work is that the model searches simultaneously for the most suitable set of oil production schemes and the corresponding energy infrastructures that satisfy the total production demands under environmental constraints, namely, CO2 emissions targets. The proposed modeling tool was validated using historical data and previous simulations of the Canadian Oil Sands operation in 2003. Likewise, the proposed model was used to study the 2020 Canadian Oil Sands operations under three different production scenarios. Also, the 2020 case study was used to show the effect of CO2 capture constraints on the oil production schemes and the energy producers. The results show that the proposed model is a practical tool for determining the production costs of the Canadian Oil Sands operations, evaluating future production schemes and energy demand scenarios, and identifying the key parameters that affect Canadian Oil Sands operations. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745740
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12641-12663[article] Integrated energy optimization model for oil sands operations [texte imprimé] / Alberto Betancourt-Torcat, Auteur ; Gloria Gutierrez, Auteur ; Ali Elkamel, Auteur . - 2012 . - pp. 12641-12663.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12641-12663
Mots-clés : Tar sand Modeling Optimization Résumé : This article presents a new energy model that predicts the energy infrastructure required to maintain oil production in the Canadian Oil Sands operation at minimum cost. Previous studies in this area have focused on the energy infrastructure for fixed energy demands (i.e., the production schemes that produce synthetic crude oil (SCO) and commercial diluted bitumen remained fixed in the calculation of the optimal infrastructure). The key novelty of this work is that the model searches simultaneously for the most suitable set of oil production schemes and the corresponding energy infrastructures that satisfy the total production demands under environmental constraints, namely, CO2 emissions targets. The proposed modeling tool was validated using historical data and previous simulations of the Canadian Oil Sands operation in 2003. Likewise, the proposed model was used to study the 2020 Canadian Oil Sands operations under three different production scenarios. Also, the 2020 case study was used to show the effect of CO2 capture constraints on the oil production schemes and the energy producers. The results show that the proposed model is a practical tool for determining the production costs of the Canadian Oil Sands operations, evaluating future production schemes and energy demand scenarios, and identifying the key parameters that affect Canadian Oil Sands operations. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745740 Exemplaires
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Titre : Mass integration as a design heuristic : improvements in the HDA process Type de document : texte imprimé Auteurs : Carlos D. Fischer, Auteur ; Oscar A. Iribarren, Auteur Année de publication : 2012 Article en page(s) : pp. 12664-12677 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mass integration Design Résumé : This paper explores mass exchanging the outlet and inlet streams of a reactor, as a design heuristic within the hierarchical process design procedure by Douglas [AlChE J. 1985, 31 (3), 353-361 and Conceptual Design of Chemical Processes; McGraw-Hill, 1988], who worked on the HDA process to test the proposal. The heuristic is used at an early stage of the hierarchy, when deciding the recycle and separation system structure of the process. If the reaction requires operating conditions with reactants in excess or that catalyze the reaction, which must be removed after the reaction, there is a concentration gradient between the inlet and outlet streams that may be used as the driving force in a mass exchanger (if such a device is available for the particular case). When applied to the HDA process, this methodology generated alternatives different from the previously proposed by other authors by resorting to a ceramic membrane gas permeation unit to perform the mass exchange of hydrogen. The performance of applying the heuristic was tested comparing the flow sheets proposed by several authors with and without this mass exchanger. The success of implementing this mass exchange networks synthesis concept was dependent on the concentration of the component to be transferred in the rich stream (i.e., it works if there is an appropriate driving force). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745741
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12664-12677[article] Mass integration as a design heuristic : improvements in the HDA process [texte imprimé] / Carlos D. Fischer, Auteur ; Oscar A. Iribarren, Auteur . - 2012 . - pp. 12664-12677.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12664-12677
Mots-clés : Mass integration Design Résumé : This paper explores mass exchanging the outlet and inlet streams of a reactor, as a design heuristic within the hierarchical process design procedure by Douglas [AlChE J. 1985, 31 (3), 353-361 and Conceptual Design of Chemical Processes; McGraw-Hill, 1988], who worked on the HDA process to test the proposal. The heuristic is used at an early stage of the hierarchy, when deciding the recycle and separation system structure of the process. If the reaction requires operating conditions with reactants in excess or that catalyze the reaction, which must be removed after the reaction, there is a concentration gradient between the inlet and outlet streams that may be used as the driving force in a mass exchanger (if such a device is available for the particular case). When applied to the HDA process, this methodology generated alternatives different from the previously proposed by other authors by resorting to a ceramic membrane gas permeation unit to perform the mass exchange of hydrogen. The performance of applying the heuristic was tested comparing the flow sheets proposed by several authors with and without this mass exchanger. The success of implementing this mass exchange networks synthesis concept was dependent on the concentration of the component to be transferred in the rich stream (i.e., it works if there is an appropriate driving force). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745741 Exemplaires
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Titre : Rigorous global optimization for dynamic systems subject to inequality path constraints Type de document : texte imprimé Auteurs : Yao Zhao, Auteur ; Mark A. Stadtherr, Auteur Année de publication : 2012 Article en page(s) : pp. 12678-12693 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization Résumé : A new approach is described for the rigorous global optimization of dynamic systems subject to inequality path constraints (IPCs). This method employs the sequential (control parametrization) approach and is based on techniques developed for the verified solution of parametric systems of ordinary differential equations. These techniques provide rigorous interval bounds on the state variables, and thus on the path constraints and objective function in the dynamic optimization problem. These techniques also provide explicit analytic representations (Taylor models) of these bounds in terms of the decision variables in the optimization problem. This facilitates the use of constraint propagation techniques that can greatly reduce the domain to be searched for the global optimum. Since IPCs are often related to safety concerns, we adopt a conservative, inner-approximation approach to constraint satisfaction. Through this approach, the search for the global optimum is restricted to a space in which continuous satisfaction of the IPCs is rigorously guaranteed, and an ∈-global optimum within this space is determined. Examples are presented that demonstrate the potential and computational performance of this approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745742
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12678-12693[article] Rigorous global optimization for dynamic systems subject to inequality path constraints [texte imprimé] / Yao Zhao, Auteur ; Mark A. Stadtherr, Auteur . - 2012 . - pp. 12678-12693.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12678-12693
Mots-clés : Optimization Résumé : A new approach is described for the rigorous global optimization of dynamic systems subject to inequality path constraints (IPCs). This method employs the sequential (control parametrization) approach and is based on techniques developed for the verified solution of parametric systems of ordinary differential equations. These techniques provide rigorous interval bounds on the state variables, and thus on the path constraints and objective function in the dynamic optimization problem. These techniques also provide explicit analytic representations (Taylor models) of these bounds in terms of the decision variables in the optimization problem. This facilitates the use of constraint propagation techniques that can greatly reduce the domain to be searched for the global optimum. Since IPCs are often related to safety concerns, we adopt a conservative, inner-approximation approach to constraint satisfaction. Through this approach, the search for the global optimum is restricted to a space in which continuous satisfaction of the IPCs is rigorously guaranteed, and an ∈-global optimum within this space is determined. Examples are presented that demonstrate the potential and computational performance of this approach. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745742 Exemplaires
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Titre : Remixing control for divided - wall columns Type de document : texte imprimé Auteurs : Hao Ling, Auteur ; Zhi Cai, Auteur ; Hao Wu, Auteur Année de publication : 2012 Article en page(s) : pp. 12694–12705 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Energy saving Résumé : The divided-wall column is an energy-saving promising technology for the separation of ternary mixtures, but control is difficult because of its complexity structure and interactions of control loops. Although a few control methods have been reported, the general control method for all ternary mixtures is still pending because of the difference of relative volatilities. In this work, we explore a new control structure by control the remixing of the intermediate at the top trays in the prefractionator section for the separation of benzene, toluene, and o-xylene. It is found that avoiding the remixing of toluene helps the divided-wall column work very close to the optimal conditions. The remixing of toluene is studied at steady state first. Then, a remixing control structure with one remixing control loop and three composition control loops is presented. Minimized energy consumption is achieved by avoiding the remixing of toluene at the top of the prefractionator. Disturbances in feed flow rate and feed compositions are used to demonstrate the effectiveness of the proposed control structure. Remixing profile analysis of intermediate compounds gives an easy and new way to design and control the divided-wall column at energy saving conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201610g
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12694–12705[article] Remixing control for divided - wall columns [texte imprimé] / Hao Ling, Auteur ; Zhi Cai, Auteur ; Hao Wu, Auteur . - 2012 . - pp. 12694–12705.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12694–12705
Mots-clés : Energy saving Résumé : The divided-wall column is an energy-saving promising technology for the separation of ternary mixtures, but control is difficult because of its complexity structure and interactions of control loops. Although a few control methods have been reported, the general control method for all ternary mixtures is still pending because of the difference of relative volatilities. In this work, we explore a new control structure by control the remixing of the intermediate at the top trays in the prefractionator section for the separation of benzene, toluene, and o-xylene. It is found that avoiding the remixing of toluene helps the divided-wall column work very close to the optimal conditions. The remixing of toluene is studied at steady state first. Then, a remixing control structure with one remixing control loop and three composition control loops is presented. Minimized energy consumption is achieved by avoiding the remixing of toluene at the top of the prefractionator. Disturbances in feed flow rate and feed compositions are used to demonstrate the effectiveness of the proposed control structure. Remixing profile analysis of intermediate compounds gives an easy and new way to design and control the divided-wall column at energy saving conditions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201610g Exemplaires
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Titre : Design and control of the glycerol tertiary butyl ethers process for the utilization of a renewable resource Type de document : texte imprimé Auteurs : Jian Kai Cheng, Auteur ; Cheng-Lin Lee, Auteur ; Yong-Tang Jhuang, Auteur Année de publication : 2012 Article en page(s) : pp. 12706-12716 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Design Résumé : In this paper, the design and control of an improved process for the manufacture of a fuel additive (glycerol tertiary butyl ethers, GTBE) from glycerol and isobutylene is developed. The improved process redirects one recycle stream, uses a stripping column instead of a flash tank to recover isobutylene, and uses a rectifying column instead of a distillation column to purify the product. Economic analysis shows that the improved process has a 22% lower total annual cost (TAC) than the best known process published in the literature. Significant increases in the selectivity of the overall process from 84.7% to 99.3% can also be realized by comparing the optimized improved design versus the original design. Dynamic simulations were also conducted and indicated that stringent product specification can be met with a simple decentralized feedback control structure despite impurities in the feed streams and also changes in the throughput. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2010516
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12706-12716[article] Design and control of the glycerol tertiary butyl ethers process for the utilization of a renewable resource [texte imprimé] / Jian Kai Cheng, Auteur ; Cheng-Lin Lee, Auteur ; Yong-Tang Jhuang, Auteur . - 2012 . - pp. 12706-12716.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12706-12716
Mots-clés : Design Résumé : In this paper, the design and control of an improved process for the manufacture of a fuel additive (glycerol tertiary butyl ethers, GTBE) from glycerol and isobutylene is developed. The improved process redirects one recycle stream, uses a stripping column instead of a flash tank to recover isobutylene, and uses a rectifying column instead of a distillation column to purify the product. Economic analysis shows that the improved process has a 22% lower total annual cost (TAC) than the best known process published in the literature. Significant increases in the selectivity of the overall process from 84.7% to 99.3% can also be realized by comparing the optimized improved design versus the original design. Dynamic simulations were also conducted and indicated that stringent product specification can be met with a simple decentralized feedback control structure despite impurities in the feed streams and also changes in the throughput. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2010516 Exemplaires
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Titre : Characterization of natural zeolite membranes for H2/CO2 separations by single gas permeation Type de document : texte imprimé Auteurs : S. A. Hosseinzadeh Hejazi, Auteur ; A. M. Avila, Auteur ; T. M. Kuznicki, Auteur Année de publication : 2012 Article en page(s) : pp. 12717-12726 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Membrane separation Gaseous permeation Carbon dioxide Zeolite Inorganic membrane Résumé : Natural zeolite membranes can be used as a model for the development of robust molecular sieve membranes with superior separation characteristics. We describe the characterization of natural clinoptilolite membranes made from dense mineral deposits by single gas H2 and CO2 permeation. Permeability values as a function of temperature and pressure were analyzed on the basis of mass transport fundamentals of gas permeation through zeolite and nonzeolite pathways. H2 and CO2 fluxes through the membranes were fitted with a model based on a combination of zeolitic, Knudsen, and viscous transports so that the selective and nonselective flux fractions could be quantified. An increase in feed pressure increased the total permeance especially at low temperatures. The membranes were also characterized by XRD, SEM, and EDX analysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745745
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12717-12726[article] Characterization of natural zeolite membranes for H2/CO2 separations by single gas permeation [texte imprimé] / S. A. Hosseinzadeh Hejazi, Auteur ; A. M. Avila, Auteur ; T. M. Kuznicki, Auteur . - 2012 . - pp. 12717-12726.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12717-12726
Mots-clés : Membrane separation Gaseous permeation Carbon dioxide Zeolite Inorganic membrane Résumé : Natural zeolite membranes can be used as a model for the development of robust molecular sieve membranes with superior separation characteristics. We describe the characterization of natural clinoptilolite membranes made from dense mineral deposits by single gas H2 and CO2 permeation. Permeability values as a function of temperature and pressure were analyzed on the basis of mass transport fundamentals of gas permeation through zeolite and nonzeolite pathways. H2 and CO2 fluxes through the membranes were fitted with a model based on a combination of zeolitic, Knudsen, and viscous transports so that the selective and nonselective flux fractions could be quantified. An increase in feed pressure increased the total permeance especially at low temperatures. The membranes were also characterized by XRD, SEM, and EDX analysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745745 Exemplaires
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Titre : Oxygen permeation through U - shaped K2NiF4 - type oxide hollow - fiber membranes Type de document : texte imprimé Auteurs : Yanying Wei, Auteur ; Jun Tang, Auteur ; Lingyi Zhou, Auteur Année de publication : 2012 Article en page(s) : pp. 12727–12734 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hollow fiber Permeation Résumé : The first oxygen permeation data for a dense hollow-fiber membrane based on a K2NiF4-type oxide are reported. The U-shaped (Pr0.9La0.1)2(Ni0.74Cu0.21Ga0.05)O4+δ (PLNCG) hollow-fiber membranes were prepared by a phase-inversion spinning process. The dependences of the oxygen permeation on the feed air flow rate, sweep helium flow rate, oxygen partial pressure on the shell side, and operating temperature were experimentally investigated. The effects of the bulk diffusion and the surface exchange on the oxygen permeation flux through the U-shaped PLNCG hollow-fiber membranes are also discussed. During around 320 h of operation, a steady oxygen permeation flux of 1.0 mL/(min·cm2) was obtained at 975 °C under conditions of an air feed flow rate of 180 mL/min and a helium sweep flow rate of 55 mL/min. XRD and SEM analyses of the spent hollow-fiber membrane showed the good stability of the U-shaped PLNCG hollow-fiber membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745746
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12727–12734[article] Oxygen permeation through U - shaped K2NiF4 - type oxide hollow - fiber membranes [texte imprimé] / Yanying Wei, Auteur ; Jun Tang, Auteur ; Lingyi Zhou, Auteur . - 2012 . - pp. 12727–12734.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12727–12734
Mots-clés : Hollow fiber Permeation Résumé : The first oxygen permeation data for a dense hollow-fiber membrane based on a K2NiF4-type oxide are reported. The U-shaped (Pr0.9La0.1)2(Ni0.74Cu0.21Ga0.05)O4+δ (PLNCG) hollow-fiber membranes were prepared by a phase-inversion spinning process. The dependences of the oxygen permeation on the feed air flow rate, sweep helium flow rate, oxygen partial pressure on the shell side, and operating temperature were experimentally investigated. The effects of the bulk diffusion and the surface exchange on the oxygen permeation flux through the U-shaped PLNCG hollow-fiber membranes are also discussed. During around 320 h of operation, a steady oxygen permeation flux of 1.0 mL/(min·cm2) was obtained at 975 °C under conditions of an air feed flow rate of 180 mL/min and a helium sweep flow rate of 55 mL/min. XRD and SEM analyses of the spent hollow-fiber membrane showed the good stability of the U-shaped PLNCG hollow-fiber membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745746 Exemplaires
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Titre : Selective extraction of palladium and platinum from hydrochloric acid solutions by trioctylammonium - based mixed ionic liquids Type de document : texte imprimé Auteurs : Shoichi Katsuta, Auteur ; Yuki Yoshimoto, Auteur ; Miho Okai, Auteur Année de publication : 2012 Article en page(s) : pp. 12735–12740 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic liquid Selective extraction Résumé : Mixtures of the protic ionic liquids trioctylammonium bis(trifluoromethanesulfonyl)amide ([TOAH][NTf2]) and trioctylammonium nitrate ([TOAH][NO3]) were investigated as extractants for platinum-group elements. The mixture of 10wt% [TOAH][NO3] in [TOAH] [NTf2] has low viscosity (274.2 mPas) and low aqueous solubility (2.6 x 10-5 mol dm-3 as the cation). With the ionic liquid mixture, Pd(II) and Pt(IV) were extracted almost quantitatively from 0.10 mol dm-3 hydrochloric acid. Under the same conditions, Na(I), Mg(II), K(I), Ca(II), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ru(III), Rh(III), and Cd(II) were only slightly extracted. It was found that the extraction of Pd and Pt increases with increasing content of [TOAH][NO3] in the mixture. The metals could be back-extracted from the ionic liquid mixture with nitric acid solution, and selective stripping of Pt was possible by controlling the concentration of nitric acid. The metal extractability of the ionic liquid mixture after the back-extraction was equivalent to that of the fresh mixture, indicating that the species composition of the mixture returned to the original state through the back-extraction process. This extraction system provides an efficient separation method for Pd and Pt in acidic chloride media using ionic liquid mixtures, which are recyclable, easy to handle, safe, and environmentally friendly. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745747
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12735–12740[article] Selective extraction of palladium and platinum from hydrochloric acid solutions by trioctylammonium - based mixed ionic liquids [texte imprimé] / Shoichi Katsuta, Auteur ; Yuki Yoshimoto, Auteur ; Miho Okai, Auteur . - 2012 . - pp. 12735–12740.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12735–12740
Mots-clés : Ionic liquid Selective extraction Résumé : Mixtures of the protic ionic liquids trioctylammonium bis(trifluoromethanesulfonyl)amide ([TOAH][NTf2]) and trioctylammonium nitrate ([TOAH][NO3]) were investigated as extractants for platinum-group elements. The mixture of 10wt% [TOAH][NO3] in [TOAH] [NTf2] has low viscosity (274.2 mPas) and low aqueous solubility (2.6 x 10-5 mol dm-3 as the cation). With the ionic liquid mixture, Pd(II) and Pt(IV) were extracted almost quantitatively from 0.10 mol dm-3 hydrochloric acid. Under the same conditions, Na(I), Mg(II), K(I), Ca(II), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ru(III), Rh(III), and Cd(II) were only slightly extracted. It was found that the extraction of Pd and Pt increases with increasing content of [TOAH][NO3] in the mixture. The metals could be back-extracted from the ionic liquid mixture with nitric acid solution, and selective stripping of Pt was possible by controlling the concentration of nitric acid. The metal extractability of the ionic liquid mixture after the back-extraction was equivalent to that of the fresh mixture, indicating that the species composition of the mixture returned to the original state through the back-extraction process. This extraction system provides an efficient separation method for Pd and Pt in acidic chloride media using ionic liquid mixtures, which are recyclable, easy to handle, safe, and environmentally friendly. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745747 Exemplaires
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Titre : High temperature CaO/Y2O3 carbon dioxide absorbent with enhanced stability for sorption - enhanced reforming applications Type de document : texte imprimé Auteurs : V. S. Derevschikov, Auteur ; A. I. Lysikov, Auteur ; A. G. Okunev, Auteur Année de publication : 2012 Article en page(s) : pp. 12741–12749 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reforming Sorption Stability Absorbent Carbon dioxide Résumé : To improve the stability of high temperature CO2 absorbent for sorption enhanced reforming applications yttria supported CaO were synthesized using two methods: calcination of mixed salt precursors and wet impregnation of yttria support. According to XRD data, CaO does not interact with the yttria matrix. However, introduction of CaO drastically changes the morphology of primary yttria particles. Increase in CaO concentration results in gradual plugging of the smaller pores and sintering of yttria support. The CO2 absorption uptake in recarbonation-decomposition cycles increases with increase in CaO content and reach 9.6 wt % at CaO content of 19.9 wt %. CaO recarbonation extent varies from 49 to 77%. CaO/Y2O3 absorbents are extremely stable under overheating and maintain their capacity in long series of decomposition-recarbonation cycles even after calcination at 1350 °C. The novel material resists moisture and retains its strength during storage in the air. According to tests, CaO/Y2O3 can be considered as a promising CO2 absorbent for fixed bed sorption enhanced hydrocarbons reforming. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745748
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12741–12749[article] High temperature CaO/Y2O3 carbon dioxide absorbent with enhanced stability for sorption - enhanced reforming applications [texte imprimé] / V. S. Derevschikov, Auteur ; A. I. Lysikov, Auteur ; A. G. Okunev, Auteur . - 2012 . - pp. 12741–12749.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12741–12749
Mots-clés : Reforming Sorption Stability Absorbent Carbon dioxide Résumé : To improve the stability of high temperature CO2 absorbent for sorption enhanced reforming applications yttria supported CaO were synthesized using two methods: calcination of mixed salt precursors and wet impregnation of yttria support. According to XRD data, CaO does not interact with the yttria matrix. However, introduction of CaO drastically changes the morphology of primary yttria particles. Increase in CaO concentration results in gradual plugging of the smaller pores and sintering of yttria support. The CO2 absorption uptake in recarbonation-decomposition cycles increases with increase in CaO content and reach 9.6 wt % at CaO content of 19.9 wt %. CaO recarbonation extent varies from 49 to 77%. CaO/Y2O3 absorbents are extremely stable under overheating and maintain their capacity in long series of decomposition-recarbonation cycles even after calcination at 1350 °C. The novel material resists moisture and retains its strength during storage in the air. According to tests, CaO/Y2O3 can be considered as a promising CO2 absorbent for fixed bed sorption enhanced hydrocarbons reforming. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745748 Exemplaires
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Titre : Chiral resolution of Ionic compounds by thin layer extraction Type de document : texte imprimé Auteurs : Ram Lavie, Auteur Année de publication : 2012 Article en page(s) : pp. 12750-12756 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ionic compounds Résumé : The increasing demand for enantiomer intermediates has attracted in recent years attention to liquid–liquid extraction as a scalable chiral resolution method. Thin layer extraction, a simple and effective form of liquid–liquid extraction that uses little extractant, promises economic utilization of the most selective chiral hosts. The role played by various parameters when applying thin layer extraction to the resolution of an ionic racemic mixture into its enantiomer components is analyzed. This analysis provides a critical insight that facilitates the design of a successful separation scheme. It transpires that, given a suitable host, certain conditions concerning the host concentration and the pH and rate of the feed and strip solutions must be balanced to obtain optimum enantioseparation or even to obtain any separation at all. A calculated example that is based on experimental data from the published literature indicates that a simple thin layer extractor, using a crown ether host, is capable of separating an ionic racemic mixture into substantially pure enantiomer products at a high yield. It appears that thin layer extraction has some promising features to become an interesting alternative for other extraction-based techniques. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201596n
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12750-12756[article] Chiral resolution of Ionic compounds by thin layer extraction [texte imprimé] / Ram Lavie, Auteur . - 2012 . - pp. 12750-12756.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12750-12756
Mots-clés : Ionic compounds Résumé : The increasing demand for enantiomer intermediates has attracted in recent years attention to liquid–liquid extraction as a scalable chiral resolution method. Thin layer extraction, a simple and effective form of liquid–liquid extraction that uses little extractant, promises economic utilization of the most selective chiral hosts. The role played by various parameters when applying thin layer extraction to the resolution of an ionic racemic mixture into its enantiomer components is analyzed. This analysis provides a critical insight that facilitates the design of a successful separation scheme. It transpires that, given a suitable host, certain conditions concerning the host concentration and the pH and rate of the feed and strip solutions must be balanced to obtain optimum enantioseparation or even to obtain any separation at all. A calculated example that is based on experimental data from the published literature indicates that a simple thin layer extractor, using a crown ether host, is capable of separating an ionic racemic mixture into substantially pure enantiomer products at a high yield. It appears that thin layer extraction has some promising features to become an interesting alternative for other extraction-based techniques. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201596n Exemplaires
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Titre : A new algorithm for the determination of product sequences in azeotropic batch distillation Type de document : texte imprimé Auteurs : Laszlo Hegely, Auteur ; Peter Lang, Auteur Année de publication : 2012 Article en page(s) : pp. 12757-12766 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Distillation Batchwise Azeotropic mixture Algorithm Résumé : In multicomponent azeotropic mixtures (e.g., waste solvents), the products obtainable by batch distillation and their maximal amount is highly dependent on the charge composition. A method is presented for the determination of product sequences for any number of components based only on the temperatures of pure components and azeotropes, and azeotropic compositions, without the knowledge of further VLE data. The method is suitable for heteroazeotropes and for taking pressure change into consideration, as well. The stability of fixed points is determined with the assumption that Serafimov topological class of the mixture occurs in Reshetov's statistics. On the basis of the stabilities, we enumerate all feasible product sequences using the algorithm of [Ahmad, B. S.; Zhang, Y.; Barton, P. 1. Product Sequences in Azeotropic Batch Distillation. AlChE Journal 1998, 44, 5, 1051-1070.]. Finally, the relative amount of cuts are determined assuming maximal separation for the given charge composition. The results are presented for the systems acetone-chloroform-methanol-ethanol-benzene and methanol-tetrahydrofuran-ethyl acetate—ethanol—isopropyl alcohol-water. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745750
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12757-12766[article] A new algorithm for the determination of product sequences in azeotropic batch distillation [texte imprimé] / Laszlo Hegely, Auteur ; Peter Lang, Auteur . - 2012 . - pp. 12757-12766.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12757-12766
Mots-clés : Distillation Batchwise Azeotropic mixture Algorithm Résumé : In multicomponent azeotropic mixtures (e.g., waste solvents), the products obtainable by batch distillation and their maximal amount is highly dependent on the charge composition. A method is presented for the determination of product sequences for any number of components based only on the temperatures of pure components and azeotropes, and azeotropic compositions, without the knowledge of further VLE data. The method is suitable for heteroazeotropes and for taking pressure change into consideration, as well. The stability of fixed points is determined with the assumption that Serafimov topological class of the mixture occurs in Reshetov's statistics. On the basis of the stabilities, we enumerate all feasible product sequences using the algorithm of [Ahmad, B. S.; Zhang, Y.; Barton, P. 1. Product Sequences in Azeotropic Batch Distillation. AlChE Journal 1998, 44, 5, 1051-1070.]. Finally, the relative amount of cuts are determined assuming maximal separation for the given charge composition. The results are presented for the systems acetone-chloroform-methanol-ethanol-benzene and methanol-tetrahydrofuran-ethyl acetate—ethanol—isopropyl alcohol-water. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745750 Exemplaires
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Titre : Three - liquid - phase extraction : a new approach for simultaneous enrichment and separation of Cr(III) and Cr(VI) Type de document : texte imprimé Auteurs : Keng Xie, Auteur ; Kun Huang, Auteur ; Liangrong Yang, Auteur Année de publication : 2012 Article en page(s) : pp. 12767-12773 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid phase Résumé : A novel and simple three-liquid-phase extraction (TLPE) approach was developed for the simultaneous removal and separation of Cr(III) and Cr(VI) from aqueous solutions. The proposed three-liquid-phase system (TLPS) consists of di(2-ethylhexyl)phosphoric acid (D2EHPA), poly(ethylene glycol) (PEG) with a molecularweight of 2000, and (NH4)2SO4. The effects of various factors including the aqueous solution pH, amounts of (NH4)2SO4 and PEG, initial chromium amount, D2EHPA concentration, phase-mixing time, and diluent on the three-phase partitioning behavior of Cr(III) and Cr(VI) were evaluated. The distribution behavior of the two oxidation states of chromium was found to be highly pH-dependent. Cr(III) preferred the D2EHPA-rich top phase through a cation-exchange reaction, whereas Cr(VI) was enriched in the PEG-rich middle phase through ion-pair formation. By appropriate selection of the extraction conditions, nearly all of the Cr(III) was extracted into the D2EHPA top phase, and more than 90% of the Cr(VI) was transferred into the PEG-rich middle phase within 5 min. The present work highlights the possibility of using the TLPE approach for the extraction and separation of two different oxidation states of metal ions, such as Cr(III) and Cr(VI), in a single extraction step. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745751
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12767-12773[article] Three - liquid - phase extraction : a new approach for simultaneous enrichment and separation of Cr(III) and Cr(VI) [texte imprimé] / Keng Xie, Auteur ; Kun Huang, Auteur ; Liangrong Yang, Auteur . - 2012 . - pp. 12767-12773.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12767-12773
Mots-clés : Liquid phase Résumé : A novel and simple three-liquid-phase extraction (TLPE) approach was developed for the simultaneous removal and separation of Cr(III) and Cr(VI) from aqueous solutions. The proposed three-liquid-phase system (TLPS) consists of di(2-ethylhexyl)phosphoric acid (D2EHPA), poly(ethylene glycol) (PEG) with a molecularweight of 2000, and (NH4)2SO4. The effects of various factors including the aqueous solution pH, amounts of (NH4)2SO4 and PEG, initial chromium amount, D2EHPA concentration, phase-mixing time, and diluent on the three-phase partitioning behavior of Cr(III) and Cr(VI) were evaluated. The distribution behavior of the two oxidation states of chromium was found to be highly pH-dependent. Cr(III) preferred the D2EHPA-rich top phase through a cation-exchange reaction, whereas Cr(VI) was enriched in the PEG-rich middle phase through ion-pair formation. By appropriate selection of the extraction conditions, nearly all of the Cr(III) was extracted into the D2EHPA top phase, and more than 90% of the Cr(VI) was transferred into the PEG-rich middle phase within 5 min. The present work highlights the possibility of using the TLPE approach for the extraction and separation of two different oxidation states of metal ions, such as Cr(III) and Cr(VI), in a single extraction step. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745751 Exemplaires
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Titre : Graph- based method for the automated calculation of thermochemical properties of components and intermediate species in the hydroprocessing of light oil fractions Type de document : texte imprimé Auteurs : Ytalo O. Dávila G., Auteur ; Jorge M. Martinis C., Auteur Année de publication : 2012 Article en page(s) : pp. 12774–12783 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermochemical properties Hydroprocessing Résumé : A method based on graph theory has been formulated to estimate some key thermochemical properties commonly utilized in modeling acid-catalyzed transformations of hydrocarbons at the elementary step level. Presently, modeling techniques for these transformations frequently convey the computer-aided generation of reaction networks involving a very large number of molecules and intermediate species such as carbenium ions. Although quantum mechanical calculations have been widely used to estimate thermodynamic properties of carbenium ions accurately, the current performance of such techniques is yet insufficient for very large sets of species. The proposed method handles this problem by simply analyzing the connectivity of the carbon atoms within a molecule, which is less demanding from a computational point of view. Thus, it is possible to obtain information on the contributions from different structural groups and their indistinguishability, making property estimation straightforward. This work presents a set of rules for calculating the symmetry numbers of hydrocarbons with up to 2 rings, and Benson-like structural contribution groups for estimating the enthalpy of carbenium ions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101657v
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12774–12783[article] Graph- based method for the automated calculation of thermochemical properties of components and intermediate species in the hydroprocessing of light oil fractions [texte imprimé] / Ytalo O. Dávila G., Auteur ; Jorge M. Martinis C., Auteur . - 2012 . - pp. 12774–12783.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12774–12783
Mots-clés : Thermochemical properties Hydroprocessing Résumé : A method based on graph theory has been formulated to estimate some key thermochemical properties commonly utilized in modeling acid-catalyzed transformations of hydrocarbons at the elementary step level. Presently, modeling techniques for these transformations frequently convey the computer-aided generation of reaction networks involving a very large number of molecules and intermediate species such as carbenium ions. Although quantum mechanical calculations have been widely used to estimate thermodynamic properties of carbenium ions accurately, the current performance of such techniques is yet insufficient for very large sets of species. The proposed method handles this problem by simply analyzing the connectivity of the carbon atoms within a molecule, which is less demanding from a computational point of view. Thus, it is possible to obtain information on the contributions from different structural groups and their indistinguishability, making property estimation straightforward. This work presents a set of rules for calculating the symmetry numbers of hydrocarbons with up to 2 rings, and Benson-like structural contribution groups for estimating the enthalpy of carbenium ions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101657v Exemplaires
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Titre : Continuous solventless extrusion process for producing sodium carboxymethyl starch suitable for disintegrant applications in solid dosage forms Type de document : texte imprimé Auteurs : Pratik N. Bhandari, Auteur ; Milford A. Hanna, Auteur Année de publication : 2012 Article en page(s) : pp. 12784-12789 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Extrusion Résumé : Sodium carboxymethyl starch (CMS) was prepared using an extruder as a continuous solventless chemical reactor. The effects of NaOH, H2O, temperature, ethanol, sodium monochloro acetate (SMCA), sodium tripolyphosphate (STPP), citric acid, epichlorohydrin, and screw configuration on the degree of substitution (DS) and swelling properties of CMS were studied. Using these factors, CMS with the DS required for pharmaceutical disintegrant applications (0.22-0.35) was prepared. By modifying the water/ethanol ratio in the formulations and avoiding excess gelatinization caused by use of NaOH solution, CMS with rapid swelling properties in an aqueous medium, essential for superdisintegrant applications in solid dosage forms, was obtained. Both corn and potato starches were used to prepare the CMS. The carboxymethyl starch, with rapid swelling properties, was characterized using Fourier-transform infrared spectroscopy and scanning electron microscopy. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745753
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12784-12789[article] Continuous solventless extrusion process for producing sodium carboxymethyl starch suitable for disintegrant applications in solid dosage forms [texte imprimé] / Pratik N. Bhandari, Auteur ; Milford A. Hanna, Auteur . - 2012 . - pp. 12784-12789.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12784-12789
Mots-clés : Extrusion Résumé : Sodium carboxymethyl starch (CMS) was prepared using an extruder as a continuous solventless chemical reactor. The effects of NaOH, H2O, temperature, ethanol, sodium monochloro acetate (SMCA), sodium tripolyphosphate (STPP), citric acid, epichlorohydrin, and screw configuration on the degree of substitution (DS) and swelling properties of CMS were studied. Using these factors, CMS with the DS required for pharmaceutical disintegrant applications (0.22-0.35) was prepared. By modifying the water/ethanol ratio in the formulations and avoiding excess gelatinization caused by use of NaOH solution, CMS with rapid swelling properties in an aqueous medium, essential for superdisintegrant applications in solid dosage forms, was obtained. Both corn and potato starches were used to prepare the CMS. The carboxymethyl starch, with rapid swelling properties, was characterized using Fourier-transform infrared spectroscopy and scanning electron microscopy. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745753 Exemplaires
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Titre : Prediction of flash points of organosilicon compounds by structure group contribution approach Type de document : texte imprimé Auteurs : Gow-Bin Wang, Auteur ; Chan-Cheng Chen, Auteur ; Horng-Jang Liaw, Auteur Année de publication : 2012 Article en page(s) : pp. 12790–12796 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Organosilicon compounds Résumé : Flash point (FP) is the primary property to evaluate fire hazards of a flammable liquid. In most countries regulations for safe handing, transporting, and storage of liquid chemicals mainly depend on the FPs of liquid chemicals. Due to the advancement of technology in discovery or synthesis of new compounds, FP data are desirable for related industries, but there is often a significant gap between the demand for such data and their availability. Thus, a reliable method to predict the FPs of flammable compounds seems very important in this regard. In the present work a predictive model of FP for organosilicon compounds is proposed via the structure group contribution (SGC) approach. This model is built up by using a training set of 184 organosilicon compounds with the fitting ability (R2) of 0.9330, the average error of 8.91 K, and the average error in percentage of 2.84%. The predictive capability of the proposed model has been demonstrated on a testing set of 46 organosilicon compounds with the predictive capability (Q2) of 0.8868, the average error of 11.15 K, and the average error in percentage of 3.66%. Because the known error for measuring FP by experiment is reported to be about 6–10 K, the proposed method offers a reasonable estimate of the FP for organosilicon compounds. Moreover, the proposed SGC model requires only the molecular structure of a compound to estimate its FP, so it also offers an effective way to approximate the FP of a novel chemical for which its quantity is still not readily available for measuring its FP by experiments. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201132v
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12790–12796[article] Prediction of flash points of organosilicon compounds by structure group contribution approach [texte imprimé] / Gow-Bin Wang, Auteur ; Chan-Cheng Chen, Auteur ; Horng-Jang Liaw, Auteur . - 2012 . - pp. 12790–12796.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12790–12796
Mots-clés : Organosilicon compounds Résumé : Flash point (FP) is the primary property to evaluate fire hazards of a flammable liquid. In most countries regulations for safe handing, transporting, and storage of liquid chemicals mainly depend on the FPs of liquid chemicals. Due to the advancement of technology in discovery or synthesis of new compounds, FP data are desirable for related industries, but there is often a significant gap between the demand for such data and their availability. Thus, a reliable method to predict the FPs of flammable compounds seems very important in this regard. In the present work a predictive model of FP for organosilicon compounds is proposed via the structure group contribution (SGC) approach. This model is built up by using a training set of 184 organosilicon compounds with the fitting ability (R2) of 0.9330, the average error of 8.91 K, and the average error in percentage of 2.84%. The predictive capability of the proposed model has been demonstrated on a testing set of 46 organosilicon compounds with the predictive capability (Q2) of 0.8868, the average error of 11.15 K, and the average error in percentage of 3.66%. Because the known error for measuring FP by experiment is reported to be about 6–10 K, the proposed method offers a reasonable estimate of the FP for organosilicon compounds. Moreover, the proposed SGC model requires only the molecular structure of a compound to estimate its FP, so it also offers an effective way to approximate the FP of a novel chemical for which its quantity is still not readily available for measuring its FP by experiments. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201132v Exemplaires
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Titre : Interaction of sulfate - reducing bacteria and carbon steel Q 235 in biofilm Type de document : texte imprimé Auteurs : Cheng Sun, Auteur ; Jin Xu, Auteur ; Fuhui Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 12797–12806 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon Steel Résumé : The effect of sulfate-reducing bacteria (SRB) on corrosion of carbon steels and interaction between SRB and the carbon steel Q 235 are investigated in soil-extract solutions (SES). The results show that corrosion rates are smaller in the SES with SRB during growing period of SRB, but bigger during dying period. The procedures of interactions of SRB and the steel are studied by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDXA). SRB do not aggregate on the surface of the steel until an anaerobic space is formed. SRB defend themselves against free oxygen by absorbing substances containing nonfree oxygen. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200952y
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12797–12806[article] Interaction of sulfate - reducing bacteria and carbon steel Q 235 in biofilm [texte imprimé] / Cheng Sun, Auteur ; Jin Xu, Auteur ; Fuhui Wang, Auteur . - 2012 . - pp. 12797–12806.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12797–12806
Mots-clés : Carbon Steel Résumé : The effect of sulfate-reducing bacteria (SRB) on corrosion of carbon steels and interaction between SRB and the carbon steel Q 235 are investigated in soil-extract solutions (SES). The results show that corrosion rates are smaller in the SES with SRB during growing period of SRB, but bigger during dying period. The procedures of interactions of SRB and the steel are studied by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDXA). SRB do not aggregate on the surface of the steel until an anaerobic space is formed. SRB defend themselves against free oxygen by absorbing substances containing nonfree oxygen. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200952y Exemplaires
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Titre : Phase equilibrium modeling of structure H clathrate hydrates of methane + water “insoluble” hydrocarbon promoter using group contribution - support vector machine technique Type de document : texte imprimé Auteurs : Ali Eslamimanesh, Auteur ; Farhad Gharagheizi, Auteur ; Amir H. Mohammadi, Auteur Année de publication : 2012 Article en page(s) : pp. 12807-12814 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Promoter Clathrate Modeling Phase equilibrium Résumé : In this work, the group contribution (GC) method is coupled with the least-squares support vector machine (LSSVM) mathematical algorithm to develop a model for representation/prediction of the dissociation conditions of structure H (sH) clathrate hydrates of methane with 21 hydrocarbon promoters namely as water "insoluble" promoters. Almost all of available literature data are studied to present a reliable model validated by the following statistical parameters: absolute average relative deviations (AARD) of the represented/predicted dissociation pressures from the reported experimental values: about 1.6%, and squared correlation coefficient: 0.99. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745756
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12807-12814[article] Phase equilibrium modeling of structure H clathrate hydrates of methane + water “insoluble” hydrocarbon promoter using group contribution - support vector machine technique [texte imprimé] / Ali Eslamimanesh, Auteur ; Farhad Gharagheizi, Auteur ; Amir H. Mohammadi, Auteur . - 2012 . - pp. 12807-12814.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12807-12814
Mots-clés : Promoter Clathrate Modeling Phase equilibrium Résumé : In this work, the group contribution (GC) method is coupled with the least-squares support vector machine (LSSVM) mathematical algorithm to develop a model for representation/prediction of the dissociation conditions of structure H (sH) clathrate hydrates of methane with 21 hydrocarbon promoters namely as water "insoluble" promoters. Almost all of available literature data are studied to present a reliable model validated by the following statistical parameters: absolute average relative deviations (AARD) of the represented/predicted dissociation pressures from the reported experimental values: about 1.6%, and squared correlation coefficient: 0.99. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745756 Exemplaires
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Titre : Hydrate equilibrium modeling for pure alkanes and mixtures of alkanes using statistical associating fluid theory Type de document : texte imprimé Auteurs : Hao Jiang, Auteur ; Hertanto Adidharma, Auteur Année de publication : 2012 Article en page(s) : pp. 12815-12823 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Résumé : A recent version of Statistical Associating Fluid Theory, namely SAFT2, coupled with the van der Waals and Platteeuw model for the hydrate phase, is applied to represent the hydrate dissociation conditions for pure alkanes and their mixtures in systems without inhibitors. The proposed model is applied to both structure I and II hydrates at temperatures above and below the freezing point of water. For binary and ternary alkane mixtures, a correction factor with only one parameter is introduced to the model. The results indicate that, for these uninhibited systems, the proposed model predicts the hydrate dissociation conditions well and captures the effect of concentration on the dissociation pressure well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745757
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12815-12823[article] Hydrate equilibrium modeling for pure alkanes and mixtures of alkanes using statistical associating fluid theory [texte imprimé] / Hao Jiang, Auteur ; Hertanto Adidharma, Auteur . - 2012 . - pp. 12815-12823.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12815-12823
Mots-clés : Modeling Résumé : A recent version of Statistical Associating Fluid Theory, namely SAFT2, coupled with the van der Waals and Platteeuw model for the hydrate phase, is applied to represent the hydrate dissociation conditions for pure alkanes and their mixtures in systems without inhibitors. The proposed model is applied to both structure I and II hydrates at temperatures above and below the freezing point of water. For binary and ternary alkane mixtures, a correction factor with only one parameter is introduced to the model. The results indicate that, for these uninhibited systems, the proposed model predicts the hydrate dissociation conditions well and captures the effect of concentration on the dissociation pressure well. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745757 Exemplaires
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Titre : Chemical composition monitoring in a batch distillation process using raman spectroscopy Type de document : texte imprimé Auteurs : Hollie C. Struthers, Auteur ; Florian M. Zehentbauer, Auteur ; Ese Ono-Sorhue, Auteur Année de publication : 2012 Article en page(s) : pp. 12824-12830 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Distillation Batchwise Surveillance Chemical composition Résumé : Raman spectroscopy was used to monitor the batch distillation of an ethanol/water mixture in a sieve-plate column. The chemical composition of the top product was determined as a function of process time. Four different experimental runs with systematically varied heating and reflux strategies were studied. The results show that the reflux ratio influences the process timing as well as the product quality, whereas the heating strategy impacts the timing only. In the second part of this work, we demonstrate that the Raman technique can also be applied to hydrocarbon systems that are relevant in the oil and gas industries. For this purpose, hexane isomers and their mixtures were studied. The results show that, even though they exhibit very similar structure, the individual compounds can be identified and, moreover, quantified in a mixture. In conclusion, Raman spectroscopy is a useful and versatile tool for monitoring practical distillation processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745758
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12824-12830[article] Chemical composition monitoring in a batch distillation process using raman spectroscopy [texte imprimé] / Hollie C. Struthers, Auteur ; Florian M. Zehentbauer, Auteur ; Ese Ono-Sorhue, Auteur . - 2012 . - pp. 12824-12830.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12824-12830
Mots-clés : Distillation Batchwise Surveillance Chemical composition Résumé : Raman spectroscopy was used to monitor the batch distillation of an ethanol/water mixture in a sieve-plate column. The chemical composition of the top product was determined as a function of process time. Four different experimental runs with systematically varied heating and reflux strategies were studied. The results show that the reflux ratio influences the process timing as well as the product quality, whereas the heating strategy impacts the timing only. In the second part of this work, we demonstrate that the Raman technique can also be applied to hydrocarbon systems that are relevant in the oil and gas industries. For this purpose, hexane isomers and their mixtures were studied. The results show that, even though they exhibit very similar structure, the individual compounds can be identified and, moreover, quantified in a mixture. In conclusion, Raman spectroscopy is a useful and versatile tool for monitoring practical distillation processes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745758 Exemplaires
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Titre : Predicting the viscosity of asymmetric hydrocarbon mixtures with the expanded fluid viscosity correlation Type de document : texte imprimé Auteurs : H. Motahhari, Auteur ; M. A. Satyro, Auteur ; Harvey W. Yarranton, Auteur Année de publication : 2012 Article en page(s) : pp. 12831-12843 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Correlation analysis Viscosity Prediction Résumé : Mass-based mixing rules are proposed for the Expanded Fluid viscosity correlation that are suitable for asymmetric mixtures and replace the original volumetric mixing rules. The Expanded Fluid correlation provides viscosity values as a function of fluid density and characterizes each pure compound with three fluid-specific parameters: c2, ρs° and c3, when using experimental densities and two parameters, c2, ρs°, when using a cubic equation of state. The proposed set of mixing rules predicts the viscosity of over 90 binary mixtures with overall average absolute relative deviations (AARD) of 2.9% and 7.8% using measured densities and densities estimated from an equation of state, respectively. To improve the predictions in equation of state applications, a binary interaction parameter is introduced to the mixing rules, compensating for inaccuracies associated with density predictions from simple cubic equations of state. Using fitted interaction parameters, the overall AARD is 3.6%. The binary interaction parameters are generalized as a function of the molecular weight and Watson K-factor. Using these generalized binary interaction parameters, the overall AARD is reduced to 5.4% for over 90 binary mixtures. The proposed mixing rules and the general binary interaction parameters correlations are also tested on an independent data set which includes 40 binary, ternary, and multicomponent mixtures. The overall AARDs are 8.4% using measured densities and 11.6 and 7.1% using equation-of-state based densities with zero and generalized binary interaction parameters, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745759
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12831-12843[article] Predicting the viscosity of asymmetric hydrocarbon mixtures with the expanded fluid viscosity correlation [texte imprimé] / H. Motahhari, Auteur ; M. A. Satyro, Auteur ; Harvey W. Yarranton, Auteur . - 2012 . - pp. 12831-12843.
Chimie industrielle
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12831-12843
Mots-clés : Correlation analysis Viscosity Prediction Résumé : Mass-based mixing rules are proposed for the Expanded Fluid viscosity correlation that are suitable for asymmetric mixtures and replace the original volumetric mixing rules. The Expanded Fluid correlation provides viscosity values as a function of fluid density and characterizes each pure compound with three fluid-specific parameters: c2, ρs° and c3, when using experimental densities and two parameters, c2, ρs°, when using a cubic equation of state. The proposed set of mixing rules predicts the viscosity of over 90 binary mixtures with overall average absolute relative deviations (AARD) of 2.9% and 7.8% using measured densities and densities estimated from an equation of state, respectively. To improve the predictions in equation of state applications, a binary interaction parameter is introduced to the mixing rules, compensating for inaccuracies associated with density predictions from simple cubic equations of state. Using fitted interaction parameters, the overall AARD is 3.6%. The binary interaction parameters are generalized as a function of the molecular weight and Watson K-factor. Using these generalized binary interaction parameters, the overall AARD is reduced to 5.4% for over 90 binary mixtures. The proposed mixing rules and the general binary interaction parameters correlations are also tested on an independent data set which includes 40 binary, ternary, and multicomponent mixtures. The overall AARDs are 8.4% using measured densities and 11.6 and 7.1% using equation-of-state based densities with zero and generalized binary interaction parameters, respectively. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745759 Exemplaires
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