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Vol. 51 N° 51 - Décembre 2012 [texte imprimé] . - 2012 . - p. 16531–16764 : ill. ; 28 cm. Chemical engineering Langues : Anglais (eng)
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Ajouter le résultat dans votre panierKinetic model of melamine phosphate precipitation / Barbara Cichy in Industrial & engineering chemistry research, Vol. 51 N° 51 (Décembre 2012)
Titre : Kinetic model of melamine phosphate precipitation Type de document : texte imprimé Auteurs : Barbara Cichy, Auteur ; Ewa Kuzdzal, Auteur Année de publication : 2012 Article en page(s) : pp. 16531–16536 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Kinetic Phosphate Résumé : The kinetics of the melamine phosphate precipitation reaction under stable mixing conditions and at constant temperature were described along with the morphology of the crystals obtained. The kinetics of the reaction between melamine and phosphoric acid was described using a model of crystallization which included a stage of rapid dissolution of solid melamine dispersed in water in phosphoric acid, followed by nucleation and growth of sparingly soluble crystals of melamine phosphate. Experimental results have confirmed the assumptions made. The size and shape of the obtained melamine phosphate particles is important for the size and shape of the product of the second reaction—melamine polyphosphate. This allows for a certain scope of control over the process of shaping the particles of plastics filler—melamine polyphosphate. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3020928
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16531–16536[article] Kinetic model of melamine phosphate precipitation [texte imprimé] / Barbara Cichy, Auteur ; Ewa Kuzdzal, Auteur . - 2012 . - pp. 16531–16536.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16531–16536
Mots-clés : Kinetic Phosphate Résumé : The kinetics of the melamine phosphate precipitation reaction under stable mixing conditions and at constant temperature were described along with the morphology of the crystals obtained. The kinetics of the reaction between melamine and phosphoric acid was described using a model of crystallization which included a stage of rapid dissolution of solid melamine dispersed in water in phosphoric acid, followed by nucleation and growth of sparingly soluble crystals of melamine phosphate. Experimental results have confirmed the assumptions made. The size and shape of the obtained melamine phosphate particles is important for the size and shape of the product of the second reaction—melamine polyphosphate. This allows for a certain scope of control over the process of shaping the particles of plastics filler—melamine polyphosphate. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3020928 Exemplaires
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Titre : Dissolution of Cr2O3(s) and the behavior of chromium in concentrated NaOH solutions Type de document : texte imprimé Auteurs : Barbara Zydorczak, Auteur ; Peter M. May, Auteur ; Danielle P. Meyrick, Auteur Année de publication : 2012 Article en page(s) : pp. 16537–16543 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Hydroxide Résumé : The solubility of Cr2O3(s) in (1 and 6) mol kg–1 sodium hydroxide solutions has been investigated at 25 °C. Even after 75 days of solid/solution contact the apparent solubility continued to increase slowly. Analysis of the solution phase by UV–vis spectrophotometry revealed that all of the dissolved chromium was present as Cr(VI), in the form of CrO42–(aq); no Cr(III) could be detected. Consistent with this finding, Cr(III) dissolved in 6 mol kg–1 NaOH was found to be oxidized to CrO42–(aq) over of period of days. No significant changes to the solid phase, Cr2O3(cr), were found, either by X-ray diffraction or by X-ray photoelectron spectroscopy, as a result of its contact with NaOH(aq). Both CrO42– and Cr(III) were found to be unreactive toward a range of organic and inorganic compounds in 6 mol kg–1 NaOH over many days at ambient temperatures. However, CrO42– catalyzed the decomposition of L-ascorbate, and was rapidly reduced by elemental Zn to Cr(III) in NaOH(aq). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302096e
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16537–16543[article] Dissolution of Cr2O3(s) and the behavior of chromium in concentrated NaOH solutions [texte imprimé] / Barbara Zydorczak, Auteur ; Peter M. May, Auteur ; Danielle P. Meyrick, Auteur . - 2012 . - pp. 16537–16543.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16537–16543
Mots-clés : Hydroxide Résumé : The solubility of Cr2O3(s) in (1 and 6) mol kg–1 sodium hydroxide solutions has been investigated at 25 °C. Even after 75 days of solid/solution contact the apparent solubility continued to increase slowly. Analysis of the solution phase by UV–vis spectrophotometry revealed that all of the dissolved chromium was present as Cr(VI), in the form of CrO42–(aq); no Cr(III) could be detected. Consistent with this finding, Cr(III) dissolved in 6 mol kg–1 NaOH was found to be oxidized to CrO42–(aq) over of period of days. No significant changes to the solid phase, Cr2O3(cr), were found, either by X-ray diffraction or by X-ray photoelectron spectroscopy, as a result of its contact with NaOH(aq). Both CrO42– and Cr(III) were found to be unreactive toward a range of organic and inorganic compounds in 6 mol kg–1 NaOH over many days at ambient temperatures. However, CrO42– catalyzed the decomposition of L-ascorbate, and was rapidly reduced by elemental Zn to Cr(III) in NaOH(aq). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302096e Exemplaires
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Titre : A Thermodynamic approach to olefin product distribution in fischer–tropsch synthesis Type de document : texte imprimé Auteurs : Xiaojun Lu, Auteur ; Diane Hildebrandt, Auteur ; Xinying Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 16544-16551 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Fischer Tropsch synthesis Résumé : Conventional Fischer―Tropsch (FT) experiments were performed in both a continuously stirred tank reactor (CSTR) and a plug-flow reactor (PFR) on a TiO2-supported cobalt catalyst. The olefin/paraffin ratios for short-chain hydrocarbons (C2―C5) were found to change when the reaction conditions were kept constant in a CSTR, while the ratio of adjacent olefins (for example, C4H8/C3H6) remained unchanged. In the experiments with a fixed-bed reactor, the temperature was varied from 210―250 °C and different flow rates ranging from 1.8―5.4 NL h―1 g-cat―1. The ratio of adjacent olefins was found to be constant under these conditions as well. After proposing a thermodynamic model for olefin product distribution, we compared the results that the model predicted with those obtained in the experiments, and found that there is good agreement between the thermodynamic predictions and the measured distributions. This supports the postulation that the olefin distribution in the Fischer-Tropsch synthesis (FTS) reaction might be determined by thermodynamics. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755617
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16544-16551[article] A Thermodynamic approach to olefin product distribution in fischer–tropsch synthesis [texte imprimé] / Xiaojun Lu, Auteur ; Diane Hildebrandt, Auteur ; Xinying Liu, Auteur . - 2012 . - pp. 16544-16551.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16544-16551
Mots-clés : Fischer Tropsch synthesis Résumé : Conventional Fischer―Tropsch (FT) experiments were performed in both a continuously stirred tank reactor (CSTR) and a plug-flow reactor (PFR) on a TiO2-supported cobalt catalyst. The olefin/paraffin ratios for short-chain hydrocarbons (C2―C5) were found to change when the reaction conditions were kept constant in a CSTR, while the ratio of adjacent olefins (for example, C4H8/C3H6) remained unchanged. In the experiments with a fixed-bed reactor, the temperature was varied from 210―250 °C and different flow rates ranging from 1.8―5.4 NL h―1 g-cat―1. The ratio of adjacent olefins was found to be constant under these conditions as well. After proposing a thermodynamic model for olefin product distribution, we compared the results that the model predicted with those obtained in the experiments, and found that there is good agreement between the thermodynamic predictions and the measured distributions. This supports the postulation that the olefin distribution in the Fischer-Tropsch synthesis (FTS) reaction might be determined by thermodynamics. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755617 Exemplaires
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Titre : Experimental and modeling studies of the degradation of estrogen hormones in aqueous TiO2 suspensions under simulated solar radiation Type de document : texte imprimé Auteurs : Zacharias Frontistis, Auteur ; Catherine Drosou, Auteur ; Konstantina Tyrovola, Auteur Année de publication : 2012 Article en page(s) : pp. 16552–16563 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Estrogen hormones Aqueous Résumé : The efficiency of TiO2 photocatalysis to degrade three estrogen hormones, that is, 17α-ethynylestradiol (EE2), estrone (E1), and 17β-estradiol (E2), in environmentally relevant samples was investigated. Radiation at a photon flux of 1.7 × 10–7 einstein/s was provided by a solar simulator and experiments were conducted at various TiO2 loadings (25–1500 mg/L), estrogen concentrations (85–300 μg/L in individual solutions and 400 μg/L in mixture), and water matrices (ultrapure water, drinking water, and secondary treated wastewater). Changes in estrogen concentration were followed by high performance liquid chromatography and estrogenicity by the yeast estrogen screening assay. Aeroxide P25, a commercially available mixture of 75:25 anatase/rutile, was considerably more active than carbon-doped and undoped anatase titania, with degradation increasing with increasing catalyst loading and treatment time. The organic and inorganic constituents typically found in wastewater and drinking water impeded degradation presumably due to the scavenging of oxidizing species. For example, the time needed for complete 100 μg/L EE2 degradation in pure water was an order of magnitude lower than that in wastewater. The three estrogens exhibited comparable reactivity, with E1 being slightly more reactive than the rest. Degradation in multicomponent mixtures was slower than in individual solutions, thus implying estrogen competition for oxidizing species. Although the mixture of three in wastewater could be degraded fully after 120 min, overall estrogenicity was reduced by just about 30%, highlighting the role of the complex water matrix. Several oxidation products of EE2 were identified by means of LC–MS/MS and a reaction network for the photocatalytic degradation of EE2 is suggested. An artificial neural network comprising five input variables (reaction time, TiO2 and EE2 concentration, organic content, and conductivity of the water matrix), eight neurons and an output variable (conversion) was optimized, tested, and validated for EE2 degradation. The network, based on tangent sigmoid and linear transfer functions for the hidden and input/output layers, respectively, and the Levenberg–Marquardt back-propagation training algorithm, can successfully predict EE2 degradation. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300561b
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16552–16563[article] Experimental and modeling studies of the degradation of estrogen hormones in aqueous TiO2 suspensions under simulated solar radiation [texte imprimé] / Zacharias Frontistis, Auteur ; Catherine Drosou, Auteur ; Konstantina Tyrovola, Auteur . - 2012 . - pp. 16552–16563.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16552–16563
Mots-clés : Estrogen hormones Aqueous Résumé : The efficiency of TiO2 photocatalysis to degrade three estrogen hormones, that is, 17α-ethynylestradiol (EE2), estrone (E1), and 17β-estradiol (E2), in environmentally relevant samples was investigated. Radiation at a photon flux of 1.7 × 10–7 einstein/s was provided by a solar simulator and experiments were conducted at various TiO2 loadings (25–1500 mg/L), estrogen concentrations (85–300 μg/L in individual solutions and 400 μg/L in mixture), and water matrices (ultrapure water, drinking water, and secondary treated wastewater). Changes in estrogen concentration were followed by high performance liquid chromatography and estrogenicity by the yeast estrogen screening assay. Aeroxide P25, a commercially available mixture of 75:25 anatase/rutile, was considerably more active than carbon-doped and undoped anatase titania, with degradation increasing with increasing catalyst loading and treatment time. The organic and inorganic constituents typically found in wastewater and drinking water impeded degradation presumably due to the scavenging of oxidizing species. For example, the time needed for complete 100 μg/L EE2 degradation in pure water was an order of magnitude lower than that in wastewater. The three estrogens exhibited comparable reactivity, with E1 being slightly more reactive than the rest. Degradation in multicomponent mixtures was slower than in individual solutions, thus implying estrogen competition for oxidizing species. Although the mixture of three in wastewater could be degraded fully after 120 min, overall estrogenicity was reduced by just about 30%, highlighting the role of the complex water matrix. Several oxidation products of EE2 were identified by means of LC–MS/MS and a reaction network for the photocatalytic degradation of EE2 is suggested. An artificial neural network comprising five input variables (reaction time, TiO2 and EE2 concentration, organic content, and conductivity of the water matrix), eight neurons and an output variable (conversion) was optimized, tested, and validated for EE2 degradation. The network, based on tangent sigmoid and linear transfer functions for the hidden and input/output layers, respectively, and the Levenberg–Marquardt back-propagation training algorithm, can successfully predict EE2 degradation. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300561b Exemplaires
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Titre : Cobalt cementation in an ethanol–water system : Kinetics and morphology of metal aggregates Type de document : texte imprimé Auteurs : Claudio Larosa, Auteur ; Marco Salerno, Auteur ; Paolo Nanni, Auteur Année de publication : 2012 Article en page(s) : pp. 16564-16572 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Aggregate Morphology Kinetics Résumé : A cobalt cementation process in ethanol―water solvent at different temperatures is presented. A new model is proposed which takes into account the depletion of the less electropositive metal by a shrinking core technique. The model comprises a system of two ordinary differential equations whose dependent variables are the concentration of the cation undergoing cementation and the radius of the sacrificial metal particles. An analytic solution is obtained and a comparison between the present model and the traditional one is proposed. The model is validated by experimental data regression to investigate the cementation kinetics at different temperatures, and the relevant activation energy suggests the onset of a chemical control regime for all experimental runs. Finally, the cemented phase is morphologically and chemically characterized, and the size distribution of the relevant metal aggregates is determined by means of both dynamic light scattering in solution and atomic force microscopy after drop casting onto a solid substrate. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755619
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16564-16572[article] Cobalt cementation in an ethanol–water system : Kinetics and morphology of metal aggregates [texte imprimé] / Claudio Larosa, Auteur ; Marco Salerno, Auteur ; Paolo Nanni, Auteur . - 2012 . - pp. 16564-16572.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16564-16572
Mots-clés : Aggregate Morphology Kinetics Résumé : A cobalt cementation process in ethanol―water solvent at different temperatures is presented. A new model is proposed which takes into account the depletion of the less electropositive metal by a shrinking core technique. The model comprises a system of two ordinary differential equations whose dependent variables are the concentration of the cation undergoing cementation and the radius of the sacrificial metal particles. An analytic solution is obtained and a comparison between the present model and the traditional one is proposed. The model is validated by experimental data regression to investigate the cementation kinetics at different temperatures, and the relevant activation energy suggests the onset of a chemical control regime for all experimental runs. Finally, the cemented phase is morphologically and chemically characterized, and the size distribution of the relevant metal aggregates is determined by means of both dynamic light scattering in solution and atomic force microscopy after drop casting onto a solid substrate. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755619 Exemplaires
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Titre : Oxidative degradation of lurgi coal-gasification wastewater with Mn2O3, Co2O3, and CuO catalysts in supercritical water Type de document : texte imprimé Auteurs : Yuzhen Wang, Auteur ; ShuZhong Wang, Auteur ; Yang Guo, Auteur Année de publication : 2012 Article en page(s) : pp. 16573-16579 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Supercritical sta Catalyst Waste water Coal gasification Chemical degradation Oxidation Oxidative Résumé : Lurgi coal-gasification wastewater was degraded in supercritical water using Mn2O3, Co2O3, and CuO as catalysts. The experiments were performed in a batch reactor at temperatures of 380-460 °C and oxygen ratios of 1.5―3.5. The results involved evaluation of TOC and NH3―N removal efficiencies; detection of the main products in the effluent; XRD, SEM, and BET analyses of the catalysts; and detection of metal ions leached from the catalysts. Maximum TOC and NH3―N removals were found with Co2O3 catalyst at 460 °C and OR = 3.5. The effluent quality could meet class-I criteria of the Integrated Wastewater Discharge Standard (GB 8978-1996). The catalytic effects on pollutant removal were in the order Co2O3 > Mn2O3 > CuO. The major phase of Mn2O3 transformed into MnO2 with a decreasing BET surface area at 460 °C and an oxygen ratio of 3.5. Serious Cu-ion leaching occurred during the process and intensified with increasing temperature. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755620
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16573-16579[article] Oxidative degradation of lurgi coal-gasification wastewater with Mn2O3, Co2O3, and CuO catalysts in supercritical water [texte imprimé] / Yuzhen Wang, Auteur ; ShuZhong Wang, Auteur ; Yang Guo, Auteur . - 2012 . - pp. 16573-16579.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16573-16579
Mots-clés : Supercritical sta Catalyst Waste water Coal gasification Chemical degradation Oxidation Oxidative Résumé : Lurgi coal-gasification wastewater was degraded in supercritical water using Mn2O3, Co2O3, and CuO as catalysts. The experiments were performed in a batch reactor at temperatures of 380-460 °C and oxygen ratios of 1.5―3.5. The results involved evaluation of TOC and NH3―N removal efficiencies; detection of the main products in the effluent; XRD, SEM, and BET analyses of the catalysts; and detection of metal ions leached from the catalysts. Maximum TOC and NH3―N removals were found with Co2O3 catalyst at 460 °C and OR = 3.5. The effluent quality could meet class-I criteria of the Integrated Wastewater Discharge Standard (GB 8978-1996). The catalytic effects on pollutant removal were in the order Co2O3 > Mn2O3 > CuO. The major phase of Mn2O3 transformed into MnO2 with a decreasing BET surface area at 460 °C and an oxygen ratio of 3.5. Serious Cu-ion leaching occurred during the process and intensified with increasing temperature. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755620 Exemplaires
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Titre : Reaction mechanism and kinetics of dimethyl carbonate synthesis from methyl carbamate and methanol Type de document : texte imprimé Auteurs : Wenbo Zhao, Auteur ; Xianye Qin, Auteur ; Yanhong Li, Auteur Année de publication : 2012 Article en page(s) : pp. 16580–16589 Note générale : Induistrial chemistry Langues : Anglais (eng) Mots-clés : Kinetics Carbonate Methanol Résumé : The catalytic activities of many transition-metal salts for dimethyl carbonate (DMC) synthesis from methyl carbamate (MC) and methanol were evaluated in a batch reactor. The reaction mechanism and kinetics on the outstanding catalyst ZnCl2 were further investigated in detail. X-ray diffraction (XRD), thermogravimetry (TG), and differential scanning calorimetry (DSC) characterization, quantum chemical calculation, and kinetics experiments all indicated that this reaction could be divided into two processes: (1) two MC molecules coordinated with ZnCl2 via N atom to produce Zn(MC)2Cl2. This intermediate would convert to Zn(MC)(NH3)Cl2 by reacting with one methanol molecule. This process was first order, relative to ZnCl2, and zeroeth order, relative to MC, from a macrokinetics viewpoint. (2) Zn(MC)(NH3)Cl2 further reacted with another methanol molecule to yield DMC and Zn(NH3)2Cl2, one ammonia molecule of Zn(NH3)2Cl2 could be substituted by MC at experimental temperature to form Zn(MC)(NH3)Cl2 again. This process was first order to both ZnCl2 and MC, from a macrokinetics viewpoint. It should be noted that Zn(MC)2Cl2 could not appear again after the first process, and the second process is the real catalysis cycle in DMC synthesis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302245n
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16580–16589[article] Reaction mechanism and kinetics of dimethyl carbonate synthesis from methyl carbamate and methanol [texte imprimé] / Wenbo Zhao, Auteur ; Xianye Qin, Auteur ; Yanhong Li, Auteur . - 2012 . - pp. 16580–16589.
Induistrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16580–16589
Mots-clés : Kinetics Carbonate Methanol Résumé : The catalytic activities of many transition-metal salts for dimethyl carbonate (DMC) synthesis from methyl carbamate (MC) and methanol were evaluated in a batch reactor. The reaction mechanism and kinetics on the outstanding catalyst ZnCl2 were further investigated in detail. X-ray diffraction (XRD), thermogravimetry (TG), and differential scanning calorimetry (DSC) characterization, quantum chemical calculation, and kinetics experiments all indicated that this reaction could be divided into two processes: (1) two MC molecules coordinated with ZnCl2 via N atom to produce Zn(MC)2Cl2. This intermediate would convert to Zn(MC)(NH3)Cl2 by reacting with one methanol molecule. This process was first order, relative to ZnCl2, and zeroeth order, relative to MC, from a macrokinetics viewpoint. (2) Zn(MC)(NH3)Cl2 further reacted with another methanol molecule to yield DMC and Zn(NH3)2Cl2, one ammonia molecule of Zn(NH3)2Cl2 could be substituted by MC at experimental temperature to form Zn(MC)(NH3)Cl2 again. This process was first order to both ZnCl2 and MC, from a macrokinetics viewpoint. It should be noted that Zn(MC)2Cl2 could not appear again after the first process, and the second process is the real catalysis cycle in DMC synthesis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302245n Exemplaires
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Titre : Biodiesel production by esterification of oleic acid over bronsted acidic ionic liquid supported onto Fe-incorporated SBA-15 Type de document : texte imprimé Auteurs : Lin Zhang, Auteur ; Yadong Cui, Auteur ; Chunping Zhang, Auteur Année de publication : 2012 Article en page(s) : pp. 16590–16596 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Biodiesel Ionic liquid Résumé : The esterification of oleic acid with short-chain alcohols using Brønsted acidic ionic liquid supported onto Fe-incorporated SBA-15 (Fe-SBA-15) was studied to develop a green method for biodiesel production. This catalyst was prepared by immobilization of Brønsted acidic ionic liquid 1-(propyl-3-sulfonate)-3-(3-trimethoxysilylpropyl) imidazolium hydrogen sulfate ([SO3H-PIm-CPMS][HSO4]) onto Fe-SBA-15 (IL/Fe-SBA-15). The structure of the catalyst was characterized by XRD, N2 adsorption–desorption measurement, FT-IR and TEM. The results demonstrated that Fe was incorporated into the framework of SBA-15, bringing Lewis acidic site. After the ionic liquid was successfully immobilized onto the surface of Fe-SBA-15, the structure of the catalyst remained intact. This catalyst displayed relatively high catalytic activity in esterification of oleic acid with short-chain alcohols because of the synergistic effect of Lewis and Brønsted acidic sites. Under the optimum reaction conditions (reaction temperature 363 K, molar ratio of methanol to oleic acid 6: 1, catalyst amount 5 wt %, and reaction time 3 h), the conversion of oleic acid reached to 87.7% when methanol was used as reactant. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302419y
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16590–16596[article] Biodiesel production by esterification of oleic acid over bronsted acidic ionic liquid supported onto Fe-incorporated SBA-15 [texte imprimé] / Lin Zhang, Auteur ; Yadong Cui, Auteur ; Chunping Zhang, Auteur . - 2012 . - pp. 16590–16596.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16590–16596
Mots-clés : Biodiesel Ionic liquid Résumé : The esterification of oleic acid with short-chain alcohols using Brønsted acidic ionic liquid supported onto Fe-incorporated SBA-15 (Fe-SBA-15) was studied to develop a green method for biodiesel production. This catalyst was prepared by immobilization of Brønsted acidic ionic liquid 1-(propyl-3-sulfonate)-3-(3-trimethoxysilylpropyl) imidazolium hydrogen sulfate ([SO3H-PIm-CPMS][HSO4]) onto Fe-SBA-15 (IL/Fe-SBA-15). The structure of the catalyst was characterized by XRD, N2 adsorption–desorption measurement, FT-IR and TEM. The results demonstrated that Fe was incorporated into the framework of SBA-15, bringing Lewis acidic site. After the ionic liquid was successfully immobilized onto the surface of Fe-SBA-15, the structure of the catalyst remained intact. This catalyst displayed relatively high catalytic activity in esterification of oleic acid with short-chain alcohols because of the synergistic effect of Lewis and Brønsted acidic sites. Under the optimum reaction conditions (reaction temperature 363 K, molar ratio of methanol to oleic acid 6: 1, catalyst amount 5 wt %, and reaction time 3 h), the conversion of oleic acid reached to 87.7% when methanol was used as reactant. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302419y Exemplaires
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Titre : The Effect of addition of ZrO2 to Fe2O3 for hydrogen production by chemical looping Type de document : texte imprimé Auteurs : Wen Liu, Auteur ; John S. Dennis, Auteur ; Stuart A. Scott, Auteur Année de publication : 2012 Article en page(s) : pp. 16597–16609 Note générale : Industrial chemistry Langues : Anglais (eng) Résumé : In this paper, a synthetic mixture of ZrO2 and Fe2O3 was prepared by coprecipitation for use in chemical looping and hydrogen production. Cycling experiments in a fluidized bed showed that a material composed of 30 mol % ZrO2 and 70 mol % Fe2O3 was capable of producing hydrogen with a consistent yield of 90 mol % of the stoichiometric amount over 20 cycles of reduction and oxidation at 1123 K. Here, the iron oxide was subjected to cycles consisting of nearly 100% reduction to Fe followed by reoxidation (with steam or CO2 and then air) to Fe2O3. There was no contamination by CO of the hydrogen produced, at a lower detection limit of 500 ppm, when the conversion of Fe3O4 to Fe was kept below 90 mol %. A preliminary investigation of the reaction kinetics confirmed that the ZrO2 support does not inhibit rates of reaction compared with those observed with iron oxide alone. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302626x
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16597–16609[article] The Effect of addition of ZrO2 to Fe2O3 for hydrogen production by chemical looping [texte imprimé] / Wen Liu, Auteur ; John S. Dennis, Auteur ; Stuart A. Scott, Auteur . - 2012 . - pp. 16597–16609.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16597–16609
Résumé : In this paper, a synthetic mixture of ZrO2 and Fe2O3 was prepared by coprecipitation for use in chemical looping and hydrogen production. Cycling experiments in a fluidized bed showed that a material composed of 30 mol % ZrO2 and 70 mol % Fe2O3 was capable of producing hydrogen with a consistent yield of 90 mol % of the stoichiometric amount over 20 cycles of reduction and oxidation at 1123 K. Here, the iron oxide was subjected to cycles consisting of nearly 100% reduction to Fe followed by reoxidation (with steam or CO2 and then air) to Fe2O3. There was no contamination by CO of the hydrogen produced, at a lower detection limit of 500 ppm, when the conversion of Fe3O4 to Fe was kept below 90 mol %. A preliminary investigation of the reaction kinetics confirmed that the ZrO2 support does not inhibit rates of reaction compared with those observed with iron oxide alone. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302626x Exemplaires
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Titre : Use of nickel oxide as a catalyst for tar elimination in a chemical-looping reforming reactor operated with biomass producer gas Type de document : texte imprimé Auteurs : Nicolas Berguerand, Auteur ; Fredrik Lind, Auteur ; Mikael Israelsson, Auteur Année de publication : 2012 Article en page(s) : pp. 16610–16616 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nickel Oxide Catalyst Résumé : A secondary tar-cleaning process based on chemical-looping reforming (CLR) was investigated for upgrading biomass producer gas, derived from the Chalmers University of Technology 2-4 MW indirect gasifier. The experiments were conducted in a bench-scale CLR reactor using a manufactured nickel oxide (NiO) catalyst. Although Ni is a well-documented and efficient steam-reforming catalyst, it is susceptible to rapid deactivation under tar-rich conditions. The aim of this study was to explore the advantages of CLR as a gas-cleaning application, a process which offers continuous regeneration of the carbon deposits on catalysts. The tar-reforming performance of this Ni material and its influence on the gas composition and in particular its potential to increase the H2/CO ratio, were studied. The system was tested at reforming temperatures that ranged from 700 to 880 °C and at oxygen concentrations of 1.0% and 2.2% in the inlet feed to regenerator section. The results confirm the strong ability of the catalyst to reform tars. Higher process temperatures clearly promoted tar conversion, with 96% overall conversion at 880 °C (99% if benzene is excluded), as compared with 45% conversion at 700 °C. The hydrogen production was favored when temperature was raised, though, a maximum ratio of H2/CO of 2.2 was observed at 750 °C. Finally, no time-on-stream deactivation of the catalyst in the CLR was observed during the test, which lasted almost 7 h. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3028262?mi=sxp600&af=R&pageSize=20&searchT [...]
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16610–16616[article] Use of nickel oxide as a catalyst for tar elimination in a chemical-looping reforming reactor operated with biomass producer gas [texte imprimé] / Nicolas Berguerand, Auteur ; Fredrik Lind, Auteur ; Mikael Israelsson, Auteur . - 2012 . - pp. 16610–16616.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16610–16616
Mots-clés : Nickel Oxide Catalyst Résumé : A secondary tar-cleaning process based on chemical-looping reforming (CLR) was investigated for upgrading biomass producer gas, derived from the Chalmers University of Technology 2-4 MW indirect gasifier. The experiments were conducted in a bench-scale CLR reactor using a manufactured nickel oxide (NiO) catalyst. Although Ni is a well-documented and efficient steam-reforming catalyst, it is susceptible to rapid deactivation under tar-rich conditions. The aim of this study was to explore the advantages of CLR as a gas-cleaning application, a process which offers continuous regeneration of the carbon deposits on catalysts. The tar-reforming performance of this Ni material and its influence on the gas composition and in particular its potential to increase the H2/CO ratio, were studied. The system was tested at reforming temperatures that ranged from 700 to 880 °C and at oxygen concentrations of 1.0% and 2.2% in the inlet feed to regenerator section. The results confirm the strong ability of the catalyst to reform tars. Higher process temperatures clearly promoted tar conversion, with 96% overall conversion at 880 °C (99% if benzene is excluded), as compared with 45% conversion at 700 °C. The hydrogen production was favored when temperature was raised, though, a maximum ratio of H2/CO of 2.2 was observed at 750 °C. Finally, no time-on-stream deactivation of the catalyst in the CLR was observed during the test, which lasted almost 7 h. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3028262?mi=sxp600&af=R&pageSize=20&searchT [...] Exemplaires
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Titre : Kinetics of reversible oligomerization of l-lactic acid with a SnCl2·2H2O/p-toluenesulfonic acid catalyst Type de document : texte imprimé Auteurs : In Hak Baick, Auteur ; Carla V. Luciani, Auteur ; Seung Young Park, Auteur Année de publication : 2012 Article en page(s) : pp. 16617-16625 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Acid catalysis Kinetics Résumé : An experimental and theoretical modeling study is presented on the kinetics of reversible oligomerization of L-lactic acid and the formation of L-lactide in closed reactors with SnCl2·2H2O/p-toluenesulfonic acid as a binary catalyst mixture. The experimental data and model simulations indicate that about 10 wt % L-lactide is produced by the cyclization of two repeating units of poly(L-lactic acid) at the chain end during the oligomerization process. The effects of the catalyst and reaction temperature at 160―200 °C on the discoloration of the reaction mixture have also been investigated, and it was observed that the discoloration of the reaction mixture was quite significant in the presence of the catalyst at high temperatures. The relevant kinetic parameters for the chain-growth reaction as well as cyclic L-lactide formation reaction have been estimated for both noncatalyzed and catalyzed reversible oligomerization reactions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755625
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16617-16625[article] Kinetics of reversible oligomerization of l-lactic acid with a SnCl2·2H2O/p-toluenesulfonic acid catalyst [texte imprimé] / In Hak Baick, Auteur ; Carla V. Luciani, Auteur ; Seung Young Park, Auteur . - 2012 . - pp. 16617-16625.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16617-16625
Mots-clés : Acid catalysis Kinetics Résumé : An experimental and theoretical modeling study is presented on the kinetics of reversible oligomerization of L-lactic acid and the formation of L-lactide in closed reactors with SnCl2·2H2O/p-toluenesulfonic acid as a binary catalyst mixture. The experimental data and model simulations indicate that about 10 wt % L-lactide is produced by the cyclization of two repeating units of poly(L-lactic acid) at the chain end during the oligomerization process. The effects of the catalyst and reaction temperature at 160―200 °C on the discoloration of the reaction mixture have also been investigated, and it was observed that the discoloration of the reaction mixture was quite significant in the presence of the catalyst at high temperatures. The relevant kinetic parameters for the chain-growth reaction as well as cyclic L-lactide formation reaction have been estimated for both noncatalyzed and catalyzed reversible oligomerization reactions. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755625 Exemplaires
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Titre : Quaternary ammonium “Tannate” for antifouling coatings Type de document : texte imprimé Auteurs : Natalia Bellotti, Auteur ; Beatriz del Amo, Auteur ; Roberto Romagnoli, Auteur Année de publication : 2012 Article en page(s) : pp. 16626-16632 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Antifouling coatings Résumé : The undesirable accumulation of a wide variety of marine organisms (biofouling) on ship hulls can lead to significantly increased costs, principally by increased fuel consumption to maintain cruising speed. Generally, these coatings have bioactive compounds, called biocides. In this sense, this paper deals with the assessment of the antifouling properties of a natural product derivative obtained from "quebracho" tannin and a quaternary ammonium salt (hexadecyltrimethylammonium bromide ([CH3(CH2)15N(CH3)3]Br). Two derivatives were obtained depending on the precipitation pH (4 and 8). The bioactivity of these derivatives was assessed by means of the Artemia test. Furthermore, soluble matrix paints were prepared with two different binders: rosin/oleic acid and rosin/styrene-acrylate copolymer. The leaching of "quebracho" tannin derivatives from coatings in artificial seawater was monitored until constant values were obtained, previous to the immersion in natural environments. Finally, the antifouling activity of coatings pigmented with the "quebracho" tannin derivative was evaluated in Mar del Plata harbor (38°08'17"S―57°31'18"W). The coating obtained with the derivative obtained at pH 4 and rosin/oleic acid as binder proved to have an acceptable efficiency for 10 months. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301524r
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16626-16632[article] Quaternary ammonium “Tannate” for antifouling coatings [texte imprimé] / Natalia Bellotti, Auteur ; Beatriz del Amo, Auteur ; Roberto Romagnoli, Auteur . - 2012 . - pp. 16626-16632.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16626-16632
Mots-clés : Antifouling coatings Résumé : The undesirable accumulation of a wide variety of marine organisms (biofouling) on ship hulls can lead to significantly increased costs, principally by increased fuel consumption to maintain cruising speed. Generally, these coatings have bioactive compounds, called biocides. In this sense, this paper deals with the assessment of the antifouling properties of a natural product derivative obtained from "quebracho" tannin and a quaternary ammonium salt (hexadecyltrimethylammonium bromide ([CH3(CH2)15N(CH3)3]Br). Two derivatives were obtained depending on the precipitation pH (4 and 8). The bioactivity of these derivatives was assessed by means of the Artemia test. Furthermore, soluble matrix paints were prepared with two different binders: rosin/oleic acid and rosin/styrene-acrylate copolymer. The leaching of "quebracho" tannin derivatives from coatings in artificial seawater was monitored until constant values were obtained, previous to the immersion in natural environments. Finally, the antifouling activity of coatings pigmented with the "quebracho" tannin derivative was evaluated in Mar del Plata harbor (38°08'17"S―57°31'18"W). The coating obtained with the derivative obtained at pH 4 and rosin/oleic acid as binder proved to have an acceptable efficiency for 10 months. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301524r Exemplaires
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Titre : Electroanalytical and theoretical investigations of the corrosion inhibition behavior of Bis-1,2,4-triazole precursors EBATTand BBATT on mild steel in 0.1 N HNO3. Type de document : texte imprimé Auteurs : Sam John, Auteur ; Abraham Joseph, Auteur Année de publication : 2012 Article en page(s) : pp. 16633-16642 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Mild steel Precursor Corrosion inhibition Résumé : The inhibition of mild steel corrosion in 0.1 N nitric acid by the bis-1,2,4-triazole precursors EBATT and BBATT was investigated by potentiodynamic polarization (Tafel), electrochemical impedance spectroscopy (EIS), adsorption, and quantum chemical calculations at 300 K. Polarization studies showed that these molecules act as mixed-type inhibitors. As the electron density around the inhibitor molecules increases due to substitution, the inhibition efficiency also increases. The quantum chemical approach was also used to calculate electronic properties of the molecules to ascertain the correlation between inhibition effect and molecular structure. Experimental and theoretical studies agree well in this regard and confirm that BBATT is a better inhibitor than EBATT. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755627
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16633-16642[article] Electroanalytical and theoretical investigations of the corrosion inhibition behavior of Bis-1,2,4-triazole precursors EBATTand BBATT on mild steel in 0.1 N HNO3. [texte imprimé] / Sam John, Auteur ; Abraham Joseph, Auteur . - 2012 . - pp. 16633-16642.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16633-16642
Mots-clés : Mild steel Precursor Corrosion inhibition Résumé : The inhibition of mild steel corrosion in 0.1 N nitric acid by the bis-1,2,4-triazole precursors EBATT and BBATT was investigated by potentiodynamic polarization (Tafel), electrochemical impedance spectroscopy (EIS), adsorption, and quantum chemical calculations at 300 K. Polarization studies showed that these molecules act as mixed-type inhibitors. As the electron density around the inhibitor molecules increases due to substitution, the inhibition efficiency also increases. The quantum chemical approach was also used to calculate electronic properties of the molecules to ascertain the correlation between inhibition effect and molecular structure. Experimental and theoretical studies agree well in this regard and confirm that BBATT is a better inhibitor than EBATT. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755627 Exemplaires
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Titre : Novel gradient porous ZSM-5 zeolite membrane/PSSF composite for enhancing mass transfer of isopropanol adsorption in a structured fixed bed Type de document : texte imprimé Auteurs : Huanhao Chen, Auteur ; Huiping Zhang, Auteur ; Ying Yan, Auteur Année de publication : 2012 Article en page(s) : pp. 16643–16650 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Mass transfer Adsorption Résumé : A novel gradient porous ZSM-5 membrane/PSSF (paperlike sintered stainless steel fiber) composite was prepared by the wet layup papermaking/sintering technique and a secondary growth process. The effects of crystallization time on the morphology, thickness, and Si/Al ratio of the ZSM-5 membranes were studied. The composites were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and N2 adsorption. Adsorption behaviors of isopropanol in structured fixed beds filled with granular activated carbon (GAC) or ZSM-5 particles in the inlet of the bed and ZSM-5/PSSF composites in the outlet of the bed were investigated. Adsorption breakthrough behaviors of isopropanol in fixed beds containing only GAC or ZSM-5 particles were also studied. Theoretical breakthrough curves were predicted using the Yoon–Nelson model and compared with the experimental results. Satisfactory agreement between the theoretical breakthrough curves and the experimental data was obtained. The parameter κ′ (rate constant) of the Yoon–Nelson model was used to reflect the mass-transfer rate of isopropanol in structured fixed beds. All of the results indicate that the mass transfer was obviously enhanced by including ZSM-5/PSSF composites in the outlet of the structured fixed bed. The concept of the length of unused bed (LUB) was also used to analyze the experimental breakthrough curves. The results showed that the utilization of the bed was obviously increased by including ZSM-5/PSSF composites in the outlet of the structured fixed bed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302609r
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16643–16650[article] Novel gradient porous ZSM-5 zeolite membrane/PSSF composite for enhancing mass transfer of isopropanol adsorption in a structured fixed bed [texte imprimé] / Huanhao Chen, Auteur ; Huiping Zhang, Auteur ; Ying Yan, Auteur . - 2012 . - pp. 16643–16650.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16643–16650
Mots-clés : Mass transfer Adsorption Résumé : A novel gradient porous ZSM-5 membrane/PSSF (paperlike sintered stainless steel fiber) composite was prepared by the wet layup papermaking/sintering technique and a secondary growth process. The effects of crystallization time on the morphology, thickness, and Si/Al ratio of the ZSM-5 membranes were studied. The composites were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and N2 adsorption. Adsorption behaviors of isopropanol in structured fixed beds filled with granular activated carbon (GAC) or ZSM-5 particles in the inlet of the bed and ZSM-5/PSSF composites in the outlet of the bed were investigated. Adsorption breakthrough behaviors of isopropanol in fixed beds containing only GAC or ZSM-5 particles were also studied. Theoretical breakthrough curves were predicted using the Yoon–Nelson model and compared with the experimental results. Satisfactory agreement between the theoretical breakthrough curves and the experimental data was obtained. The parameter κ′ (rate constant) of the Yoon–Nelson model was used to reflect the mass-transfer rate of isopropanol in structured fixed beds. All of the results indicate that the mass transfer was obviously enhanced by including ZSM-5/PSSF composites in the outlet of the structured fixed bed. The concept of the length of unused bed (LUB) was also used to analyze the experimental breakthrough curves. The results showed that the utilization of the bed was obviously increased by including ZSM-5/PSSF composites in the outlet of the structured fixed bed. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302609r Exemplaires
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Titre : Fabrication of Au nanowire/pichia pastoris cell composites with hexadecyltrimethylammonium bromides as a platform for SERS detection : A microorganism-mediated approach Type de document : texte imprimé Auteurs : Miao Wang, Auteur ; Tao Kong, Auteur ; Xiaolian Jing, Auteur Année de publication : 2012 Article en page(s) : pp. 16651–16659 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Composite material Résumé : Au nanowire/Pichia pastoris cell composites were prepared using a microorganism-mediated method, where closely packed Au nanowires (AuNWs) are synthesized at high yields in the presence of hexadecyltrimethylammonium bromide (CTAB) without auxiliary seeds. The initial concentrations of ascorbic acid (AA), CTAB, and tetrachloroaurate trihydrate, as well as the amount of Pichia pastoris cells (PPCs), were optimized for the formation of AuNWs. For the formation of AuNWs, Au(III) ions were initially bound by the PPCs and then reduced by AA to produce Au nanoparticles (AuNPs) via preferential nucleation. The linear fusion of these AuNPs influenced by CTAB resulted in the formation of growing AuNWs, whereas the secondary nucleation beyond the PPCs produced small AuNPs that were subsequently consumed through Ostwald ripening during the aging of AuNWs. These AuNW/PPCs composites could be effectively used as surface-enhanced Raman scattering substrates for the detection of rhodamine 6G. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755629
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16651–16659[article] Fabrication of Au nanowire/pichia pastoris cell composites with hexadecyltrimethylammonium bromides as a platform for SERS detection : A microorganism-mediated approach [texte imprimé] / Miao Wang, Auteur ; Tao Kong, Auteur ; Xiaolian Jing, Auteur . - 2012 . - pp. 16651–16659.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16651–16659
Mots-clés : Composite material Résumé : Au nanowire/Pichia pastoris cell composites were prepared using a microorganism-mediated method, where closely packed Au nanowires (AuNWs) are synthesized at high yields in the presence of hexadecyltrimethylammonium bromide (CTAB) without auxiliary seeds. The initial concentrations of ascorbic acid (AA), CTAB, and tetrachloroaurate trihydrate, as well as the amount of Pichia pastoris cells (PPCs), were optimized for the formation of AuNWs. For the formation of AuNWs, Au(III) ions were initially bound by the PPCs and then reduced by AA to produce Au nanoparticles (AuNPs) via preferential nucleation. The linear fusion of these AuNPs influenced by CTAB resulted in the formation of growing AuNWs, whereas the secondary nucleation beyond the PPCs produced small AuNPs that were subsequently consumed through Ostwald ripening during the aging of AuNWs. These AuNW/PPCs composites could be effectively used as surface-enhanced Raman scattering substrates for the detection of rhodamine 6G. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755629 Exemplaires
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Titre : Reducing the environmental impact of biodiesel production from vegetable oil by use of a solar-assisted steam generation system with heat storage Type de document : texte imprimé Auteurs : Robert Brunet, Auteur ; Ekaterina Antipova, Auteur ; Gonzalo Guillen-Gosalbez, Auteur Année de publication : 2012 Article en page(s) : pp. 16660–16669 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Biodiesel Vegetable oil Résumé : In this work, we address the problem of reducing the environmental impact of biodiesel plants through their integration with a solar thermal energy system that generates steam. A mathematical model of the solar energy system that includes energy storage is constructed and coupled with a rigorous simulation model of the biodiesel facility developed in Aspen Plus. The solar energy system model takes the form of a bicriteria nonlinear programming (biNLP) formulation that accounts for the simultaneous minimization of cost and global warming potential (GWP). A detailed cost and environmental analysis of the integrated facility is presented based on data available in the literature. The environmental impact is quantified in terms of contribution to GWP using the CML2001 methodology, a framework based on life cycle assessment (LCA) principles. Numerical results indicate that it is possible to reduce the current natural gas consumption required in the biodiesel facility by more than 94.87% compared to the initial base design, which results in an improvement of 19.88% in green house gases (GHG) emissions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301391h
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16660–16669[article] Reducing the environmental impact of biodiesel production from vegetable oil by use of a solar-assisted steam generation system with heat storage [texte imprimé] / Robert Brunet, Auteur ; Ekaterina Antipova, Auteur ; Gonzalo Guillen-Gosalbez, Auteur . - 2012 . - pp. 16660–16669.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16660–16669
Mots-clés : Biodiesel Vegetable oil Résumé : In this work, we address the problem of reducing the environmental impact of biodiesel plants through their integration with a solar thermal energy system that generates steam. A mathematical model of the solar energy system that includes energy storage is constructed and coupled with a rigorous simulation model of the biodiesel facility developed in Aspen Plus. The solar energy system model takes the form of a bicriteria nonlinear programming (biNLP) formulation that accounts for the simultaneous minimization of cost and global warming potential (GWP). A detailed cost and environmental analysis of the integrated facility is presented based on data available in the literature. The environmental impact is quantified in terms of contribution to GWP using the CML2001 methodology, a framework based on life cycle assessment (LCA) principles. Numerical results indicate that it is possible to reduce the current natural gas consumption required in the biodiesel facility by more than 94.87% compared to the initial base design, which results in an improvement of 19.88% in green house gases (GHG) emissions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301391h Exemplaires
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Titre : Water and n-heptane volume fractions in a rotor-stator spinning disc reactor Type de document : texte imprimé Auteurs : Frans Visscher, Auteur ; Andre Bieberle, Auteur ; Markus Schubert, Auteur Année de publication : 2012 Article en page(s) : pp. 16670–16676 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Volume fractions n heptane water Rotor stator Résumé : This paper presents the volume fractions of n-heptane and water measured in a rotor-stator spinning disc reactor. The volume fractions were measured using γ-ray tomography and photographic image analysis. The volume fractions were determined as a function of rotational disc speed, flow ratio, position in the reactor, and rotor material. In addition, the effect of the density difference between water and n-heptane was determined by dissolving potassium iodide in the water phase. Below a rotational disc speed of 75 rpm the volume fraction measured by tomography and photographic image analysis are within 10% deviation. For low rotational disc speeds, the n-heptane volume fraction decreases slightly with increasing rotational disc speed: the centrifugal force accelerates the larger n-heptane droplets to the center. At higher rotational disc speeds the droplets become smaller accordingly, the friction between the phases determines the flow, and the n-heptane volume fraction becomes equal to the n-heptane to total flow ratio. An increase in density difference from 0.31 to 0.79 kg dm–3 did not influence the volume fractions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301439s
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16670–16676[article] Water and n-heptane volume fractions in a rotor-stator spinning disc reactor [texte imprimé] / Frans Visscher, Auteur ; Andre Bieberle, Auteur ; Markus Schubert, Auteur . - 2012 . - pp. 16670–16676.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16670–16676
Mots-clés : Volume fractions n heptane water Rotor stator Résumé : This paper presents the volume fractions of n-heptane and water measured in a rotor-stator spinning disc reactor. The volume fractions were measured using γ-ray tomography and photographic image analysis. The volume fractions were determined as a function of rotational disc speed, flow ratio, position in the reactor, and rotor material. In addition, the effect of the density difference between water and n-heptane was determined by dissolving potassium iodide in the water phase. Below a rotational disc speed of 75 rpm the volume fraction measured by tomography and photographic image analysis are within 10% deviation. For low rotational disc speeds, the n-heptane volume fraction decreases slightly with increasing rotational disc speed: the centrifugal force accelerates the larger n-heptane droplets to the center. At higher rotational disc speeds the droplets become smaller accordingly, the friction between the phases determines the flow, and the n-heptane volume fraction becomes equal to the n-heptane to total flow ratio. An increase in density difference from 0.31 to 0.79 kg dm–3 did not influence the volume fractions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301439s Exemplaires
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Titre : Experimental evaluation of the targeted direct design of temperature trajectories for growth-dominated crystallization processes using an analytical crystal size distribution estimator Type de document : texte imprimé Auteurs : E. Aamir, Auteur ; C. D. Rielly, Auteur ; Z. K. Nagy, Auteur Année de publication : 2012 Article en page(s) : pp. 16677–16687 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Crystallization processes Résumé : The paper presents an experimental validation of a novel methodology for the systematic design of the set point operating curves for supersaturation-controlled, seeded crystallization processes, which produces a desired target crystal size distribution (CSD). The direct design approach is based on the idea of operating the system within the metastable zone (MSZ) bounded by the nucleation and the solubility curves. The proposed approach is based on an analytical CSD estimator, obtained by the analytical solution of the population balance equation for supersaturation-controlled growth-dominated processes. Based on the analytical estimator a design parameter for supersaturation-controlled processes is defined as a function of the supersaturation, time, and growth kinetics. Using the design parameter and the analytical CSD estimator, the temperature profiles in the time domain are determined to obtain a target distribution with a desired shape, while maintaining the constant supersaturation. The resulting temperature profile in the time domain can then be used as a set point for the temperature controller. This methodology provides a systematic targeted direct design approach for practical applications and scale-up. Experimental evaluations of two temperature trajectories designed with the proposed approach were carried out to achieve the desired target shape of the CSD. The experiments illustrate that the proposed targeted direct design approach can be used to systematically design different temperature trajectories and hence batch times, which lead to similar desired product CSD. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301610z
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16677–16687[article] Experimental evaluation of the targeted direct design of temperature trajectories for growth-dominated crystallization processes using an analytical crystal size distribution estimator [texte imprimé] / E. Aamir, Auteur ; C. D. Rielly, Auteur ; Z. K. Nagy, Auteur . - 2012 . - pp. 16677–16687.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16677–16687
Mots-clés : Crystallization processes Résumé : The paper presents an experimental validation of a novel methodology for the systematic design of the set point operating curves for supersaturation-controlled, seeded crystallization processes, which produces a desired target crystal size distribution (CSD). The direct design approach is based on the idea of operating the system within the metastable zone (MSZ) bounded by the nucleation and the solubility curves. The proposed approach is based on an analytical CSD estimator, obtained by the analytical solution of the population balance equation for supersaturation-controlled growth-dominated processes. Based on the analytical estimator a design parameter for supersaturation-controlled processes is defined as a function of the supersaturation, time, and growth kinetics. Using the design parameter and the analytical CSD estimator, the temperature profiles in the time domain are determined to obtain a target distribution with a desired shape, while maintaining the constant supersaturation. The resulting temperature profile in the time domain can then be used as a set point for the temperature controller. This methodology provides a systematic targeted direct design approach for practical applications and scale-up. Experimental evaluations of two temperature trajectories designed with the proposed approach were carried out to achieve the desired target shape of the CSD. The experiments illustrate that the proposed targeted direct design approach can be used to systematically design different temperature trajectories and hence batch times, which lead to similar desired product CSD. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301610z Exemplaires
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Titre : Ion exchange recovery of palladium(II) from acidic solutions using monodisperse lewatit SR-7 Type de document : texte imprimé Auteurs : Anna Wolowicz, Auteur ; Zbigniew Hubicki, Auteur Année de publication : 2012 Article en page(s) : pp. 16688–16696 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ion exchange Acidic solutions Résumé : This work focuses on the sorption recovery of palladium(II) present in chloride and chloride–nitrate(V) solutions on the commercial strongly basic anion exchanger Lewatit MonoPlus SR-7. Sorption, kinetic, and equilibrium studies were carried out using batch and dynamic methods. The basic parameters of sorption capacity, recovery degree, distribution coefficient, process rate, and half-exchange time were calculated. Effects of agitation speed, initial palladium(II) concentration, and total concentration of the chloride anions were tested. Regeneration and reuse of the resin was also investigated. The surface morphology of Lewatit MonoPlus SR-7 before and after the sorption process was described. Lewatit MonoPlus SR-7 is an efficient sorbent for Pd(II) ions (Langmuir capacity 197 mg/g), is characterized by good kinetic properties, and can be regenerated and reused repeatedly without decrease of capacity. Moreover, its capacity is high but decreases in the presence of aluminum ions and slightly increases with the temperature (313 K). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302304c
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16688–16696[article] Ion exchange recovery of palladium(II) from acidic solutions using monodisperse lewatit SR-7 [texte imprimé] / Anna Wolowicz, Auteur ; Zbigniew Hubicki, Auteur . - 2012 . - pp. 16688–16696.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16688–16696
Mots-clés : Ion exchange Acidic solutions Résumé : This work focuses on the sorption recovery of palladium(II) present in chloride and chloride–nitrate(V) solutions on the commercial strongly basic anion exchanger Lewatit MonoPlus SR-7. Sorption, kinetic, and equilibrium studies were carried out using batch and dynamic methods. The basic parameters of sorption capacity, recovery degree, distribution coefficient, process rate, and half-exchange time were calculated. Effects of agitation speed, initial palladium(II) concentration, and total concentration of the chloride anions were tested. Regeneration and reuse of the resin was also investigated. The surface morphology of Lewatit MonoPlus SR-7 before and after the sorption process was described. Lewatit MonoPlus SR-7 is an efficient sorbent for Pd(II) ions (Langmuir capacity 197 mg/g), is characterized by good kinetic properties, and can be regenerated and reused repeatedly without decrease of capacity. Moreover, its capacity is high but decreases in the presence of aluminum ions and slightly increases with the temperature (313 K). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302304c Exemplaires
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Titre : Adsorption of volatile organic compounds. experimental and theoretical study Type de document : texte imprimé Auteurs : Cristian C. Brunchi, Auteur ; Juan Manuel Castillo Sanchez, Auteur ; Andrzej I. Stankiewicz, Auteur Année de publication : 2012 Article en page(s) : pp. 1029-1038 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Flue gas purification Physicochemical Gas solid adsorption Fixed bed Inorganic adsorbent Activated carbon Granular material Organic adsorbate Ternary mixture Résumé : A simple mathematical model has been developed to simulate multicomponent fixed bed adsorption. The Linear Driving Force model is used to describe the intraparticle mass transfer. The competitive effect is accounted for through the multicomponent adsorption isotherm. This multicomponent equilibrium is described by the Ideal Adsorbed Solution Theory (IAST). To apply this theory, pure component adsorption isotherm data are represented by the Freundlich equation on a piecewise basis. For the prediction, operating conditions (flow rates, bed depths, input concentrations) and some characteristics of activated carbon must be known. It is also necessary to have pure component isotherm data. To demonstrate the applicability of the model, fixed bed experiments were carried out using a ternary mixture, containing methylethylketone, ethylene chloride, methylene chloride. A good agreement between calculations and experiments was obtained. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=2417229
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 1029-1038[article] Adsorption of volatile organic compounds. experimental and theoretical study [texte imprimé] / Cristian C. Brunchi, Auteur ; Juan Manuel Castillo Sanchez, Auteur ; Andrzej I. Stankiewicz, Auteur . - 2012 . - pp. 1029-1038.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 1029-1038
Mots-clés : Flue gas purification Physicochemical Gas solid adsorption Fixed bed Inorganic adsorbent Activated carbon Granular material Organic adsorbate Ternary mixture Résumé : A simple mathematical model has been developed to simulate multicomponent fixed bed adsorption. The Linear Driving Force model is used to describe the intraparticle mass transfer. The competitive effect is accounted for through the multicomponent adsorption isotherm. This multicomponent equilibrium is described by the Ideal Adsorbed Solution Theory (IAST). To apply this theory, pure component adsorption isotherm data are represented by the Freundlich equation on a piecewise basis. For the prediction, operating conditions (flow rates, bed depths, input concentrations) and some characteristics of activated carbon must be known. It is also necessary to have pure component isotherm data. To demonstrate the applicability of the model, fixed bed experiments were carried out using a ternary mixture, containing methylethylketone, ethylene chloride, methylene chloride. A good agreement between calculations and experiments was obtained. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=2417229 Exemplaires
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Titre : Solubility of methane in the ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate Type de document : texte imprimé Auteurs : Mamoun Althuluth, Auteur ; Maaike C. Kroon, Auteur ; Cor J. Peters, Auteur Année de publication : 2012 Article en page(s) : pp. 16709–16712 Note générale : Industrial chgemistry Langues : Anglais (eng) Mots-clés : Ionic liquid Methane Résumé : Previously, we found that the ionic liquid (IL) 1-ethyl-3 methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]) shows the highest carbon dioxide (CO2) solubility of all ILs studied so far. Therefore, this IL is a very interesting solvent for gas separations, such as the removal of CO2 from sour gas, as long as the solubility of methane (CH4) in the same IL is sufficiently low. In this work, we present new experimental measurements of the CH4 solubility in [emim][FAP]. This solubility has been determined by measuring the bubble point pressures for CH4 concentrations ranging from (5.2 to 15.5) mol % and within a temperature range of (293.30 to 363.42 K) using a synthetic method. The solubilities of CH4 in [emim][FAP] are compared to the CH4 solubilities in other ILs. This comparison shows that the solubility of CH4 in the various ILs slightly decreases in the order: [hmim][Tf2N] > [emim][FAP] > [bmim][Tf2N]. The solubilities of CH4 in various ILs are compared with CO2 solubilities in the same ILs, showing the much lower solubility of CH4 in all ILs studied. The high solubility of CO2 compared to CH4 in [emim][FAP] indicates the possibility of using this IL in separating CO2 from natural gas. The obtained selectivity for this separation at a temperature of 333.15 K is S = HCH4/HCO2 = 7.74, which is similar to CO2/CH4 separation ratios in other ILs (e.g., S = 8.26 for [bmim][Tf2N] and S = 6.10 for [hmim][Tf2N]). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302472t
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16709–16712[article] Solubility of methane in the ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate [texte imprimé] / Mamoun Althuluth, Auteur ; Maaike C. Kroon, Auteur ; Cor J. Peters, Auteur . - 2012 . - pp. 16709–16712.
Industrial chgemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16709–16712
Mots-clés : Ionic liquid Methane Résumé : Previously, we found that the ionic liquid (IL) 1-ethyl-3 methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]) shows the highest carbon dioxide (CO2) solubility of all ILs studied so far. Therefore, this IL is a very interesting solvent for gas separations, such as the removal of CO2 from sour gas, as long as the solubility of methane (CH4) in the same IL is sufficiently low. In this work, we present new experimental measurements of the CH4 solubility in [emim][FAP]. This solubility has been determined by measuring the bubble point pressures for CH4 concentrations ranging from (5.2 to 15.5) mol % and within a temperature range of (293.30 to 363.42 K) using a synthetic method. The solubilities of CH4 in [emim][FAP] are compared to the CH4 solubilities in other ILs. This comparison shows that the solubility of CH4 in the various ILs slightly decreases in the order: [hmim][Tf2N] > [emim][FAP] > [bmim][Tf2N]. The solubilities of CH4 in various ILs are compared with CO2 solubilities in the same ILs, showing the much lower solubility of CH4 in all ILs studied. The high solubility of CO2 compared to CH4 in [emim][FAP] indicates the possibility of using this IL in separating CO2 from natural gas. The obtained selectivity for this separation at a temperature of 333.15 K is S = HCH4/HCO2 = 7.74, which is similar to CO2/CH4 separation ratios in other ILs (e.g., S = 8.26 for [bmim][Tf2N] and S = 6.10 for [hmim][Tf2N]). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302472t Exemplaires
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Titre : Toward thermoplastic lignin polymers. Part 1. : Selective masking of phenolic hydroxyl groups in kraft lignins via methylation and oxypropylation chemistries Type de document : texte imprimé Auteurs : Hasan Sadeghifar, Auteur ; Chengzhong Cui, Auteur ; Dimitris S. Argyropoulos, Auteur Année de publication : 2012 Article en page(s) : pp. 16713–16720 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermoplastic Hydroxyl Résumé : This work offers a comprehensive understanding of the conditions required for the selective masking of the phenolic hydroxyl groups in technical kraft lignins, which is pivotal in determining their subsequent chemical and thermal reactivity. To this effect, we have examined the chemistry and developed the conditions for the facile, mild, and selective masking of the phenolic hydroxyl groups in softwood and hardwood kraft lignins. We have compared two series of methylated softwood kraft lignins synthesized using different methylation chemistries. Our data show that (when used as specified) dimethyl sulfate in aqueous NaOH selectively converts the phenolic hydroxyl groups of kraft lignin to its methylated derivatives without apparent side reactions. In contrast, methyl iodide (in the presence of excess K2CO3 in N,N-dimethylformamide) was found to be rather ineffective and unselective. Various milder methylation conditions were also examined for both softwood and hardwood kraft lignins using dimethyl sulfate, and the details of this work are documented. In addition, a series of oxypropylation reactions were also carried out using propylene oxide in aqueous NaOH. Propylene oxide was shown to selectively add (at room temperature, 0.5 M NaOH, 18 h) less than two units on average per phenolic hydroxyl group without significant additional polymerization or other side reactions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301848j
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16713–16720[article] Toward thermoplastic lignin polymers. Part 1. : Selective masking of phenolic hydroxyl groups in kraft lignins via methylation and oxypropylation chemistries [texte imprimé] / Hasan Sadeghifar, Auteur ; Chengzhong Cui, Auteur ; Dimitris S. Argyropoulos, Auteur . - 2012 . - pp. 16713–16720.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16713–16720
Mots-clés : Thermoplastic Hydroxyl Résumé : This work offers a comprehensive understanding of the conditions required for the selective masking of the phenolic hydroxyl groups in technical kraft lignins, which is pivotal in determining their subsequent chemical and thermal reactivity. To this effect, we have examined the chemistry and developed the conditions for the facile, mild, and selective masking of the phenolic hydroxyl groups in softwood and hardwood kraft lignins. We have compared two series of methylated softwood kraft lignins synthesized using different methylation chemistries. Our data show that (when used as specified) dimethyl sulfate in aqueous NaOH selectively converts the phenolic hydroxyl groups of kraft lignin to its methylated derivatives without apparent side reactions. In contrast, methyl iodide (in the presence of excess K2CO3 in N,N-dimethylformamide) was found to be rather ineffective and unselective. Various milder methylation conditions were also examined for both softwood and hardwood kraft lignins using dimethyl sulfate, and the details of this work are documented. In addition, a series of oxypropylation reactions were also carried out using propylene oxide in aqueous NaOH. Propylene oxide was shown to selectively add (at room temperature, 0.5 M NaOH, 18 h) less than two units on average per phenolic hydroxyl group without significant additional polymerization or other side reactions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301848j Exemplaires
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Titre : Viscosity models based on the free volume and frictional theories for systems at pressures to 276 MPa and temperatures to 533 K Type de document : texte imprimé Auteurs : Ward A. Burgess, Auteur ; Deepak Tapriyal, Auteur ; Isaac K. Gamwo, Auteur Année de publication : 2012 Article en page(s) : pp. 16721–16733 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Viscosity Frictional theories Résumé : This study presents methods for accurate viscosity modeling using the frictional theory (f-theory) and the free volume theory (FV theory) of viscosity at temperatures to 533 K and pressures to 276 MPa, which are high-temperature, high-pressure (HTHP) conditions associated with ultradeep porous sandstone or carbonate layers that retain crude oil or natural gas. The perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS), the HTHP-volume-translated (VT) Peng–Robinson EoS, and the HTHP-volume-translated-Soave–Redlich–Kwong EoS (HTHP-VT-PR and HTHP-VT-SRK, respectively) are used to provide input information for both the f-theory and the FV theory. Viscosity values returned by these models are compared to available experimental data for n-alkanes with carbon numbers 1–18, branched alkanes, single and double ring aromatics, and naphthenic compounds. As currently constituted, the f-theory model underpredicts viscosity by as much as 20% at pressures near 276 MPa, but this deficiency is reduced by incorporating an empirical correction term that is a function of temperature and normal melting point. Viscosity predictions from the modified f-theory are comparable with viscosity values returned by FV theory for n-alkanes, although FV theory provides better viscosity modeling than either the f-theory or the modified f-theory for branched and aromatic hydrocarbons. FV theory viscosity values are characterized by a mean absolute percent deviation (MAPD) of 3% or less from the experimental data, with the most accurate results (MAPD 2%) obtained when the PC-SAFT is used to calculate the density input needed for the FV theory calculations. However, FV theory viscosity values actually become slightly less accurate when experimental density data are used, which indicates that FV theory itself has an inherent inaccuracy at extreme conditions unrelated to the accurate prediction of the density input. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301727k
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16721–16733[article] Viscosity models based on the free volume and frictional theories for systems at pressures to 276 MPa and temperatures to 533 K [texte imprimé] / Ward A. Burgess, Auteur ; Deepak Tapriyal, Auteur ; Isaac K. Gamwo, Auteur . - 2012 . - pp. 16721–16733.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16721–16733
Mots-clés : Viscosity Frictional theories Résumé : This study presents methods for accurate viscosity modeling using the frictional theory (f-theory) and the free volume theory (FV theory) of viscosity at temperatures to 533 K and pressures to 276 MPa, which are high-temperature, high-pressure (HTHP) conditions associated with ultradeep porous sandstone or carbonate layers that retain crude oil or natural gas. The perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS), the HTHP-volume-translated (VT) Peng–Robinson EoS, and the HTHP-volume-translated-Soave–Redlich–Kwong EoS (HTHP-VT-PR and HTHP-VT-SRK, respectively) are used to provide input information for both the f-theory and the FV theory. Viscosity values returned by these models are compared to available experimental data for n-alkanes with carbon numbers 1–18, branched alkanes, single and double ring aromatics, and naphthenic compounds. As currently constituted, the f-theory model underpredicts viscosity by as much as 20% at pressures near 276 MPa, but this deficiency is reduced by incorporating an empirical correction term that is a function of temperature and normal melting point. Viscosity predictions from the modified f-theory are comparable with viscosity values returned by FV theory for n-alkanes, although FV theory provides better viscosity modeling than either the f-theory or the modified f-theory for branched and aromatic hydrocarbons. FV theory viscosity values are characterized by a mean absolute percent deviation (MAPD) of 3% or less from the experimental data, with the most accurate results (MAPD 2%) obtained when the PC-SAFT is used to calculate the density input needed for the FV theory calculations. However, FV theory viscosity values actually become slightly less accurate when experimental density data are used, which indicates that FV theory itself has an inherent inaccuracy at extreme conditions unrelated to the accurate prediction of the density input. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301727k Exemplaires
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Titre : A Novel integrated feature selection method for the rational synthesis of microporous aluminophosphate Type de document : texte imprimé Auteurs : Miao Qi, Auteur ; Jinsong Li, Auteur ; Jianzhong Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 16734–16740 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Rational synthesis Microporous Résumé : In this paper, an integrated feature selection model is proposed to explore the relationship between the synthetic factors and the specific resulting structure on the database of AlPO syntheses. Specifically, the proposed model can select the most significant synthetic factors for the generation of (6,12)-ring-containing structure. First, a random subspace method is employed to prerank the synthetic factors based on the predictive performance of a support vector machine. Then, the Fisher score is presented to rank the synthetic factors for getting a fusion weight. Finally, a sequential forward search method is utilized to select the most significant synthetic factors in view of the highest predictive performance. Specially, the principal-component-analysis method is adopted as guidance for estimating the random subspace dimension. The results are judged on the numerical prediction of (6,12)-ring-containing AlPO structures. Simultaneously, we compare our method with several classical feature selection methods. The experimental results show that the proposed model exhibits higher predictive accuracy with less synthetic factors. The results also provide an important guidance for the rational design and synthesis of microporous materials. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3019774
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16734–16740[article] A Novel integrated feature selection method for the rational synthesis of microporous aluminophosphate [texte imprimé] / Miao Qi, Auteur ; Jinsong Li, Auteur ; Jianzhong Wang, Auteur . - 2012 . - pp. 16734–16740.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16734–16740
Mots-clés : Rational synthesis Microporous Résumé : In this paper, an integrated feature selection model is proposed to explore the relationship between the synthetic factors and the specific resulting structure on the database of AlPO syntheses. Specifically, the proposed model can select the most significant synthetic factors for the generation of (6,12)-ring-containing structure. First, a random subspace method is employed to prerank the synthetic factors based on the predictive performance of a support vector machine. Then, the Fisher score is presented to rank the synthetic factors for getting a fusion weight. Finally, a sequential forward search method is utilized to select the most significant synthetic factors in view of the highest predictive performance. Specially, the principal-component-analysis method is adopted as guidance for estimating the random subspace dimension. The results are judged on the numerical prediction of (6,12)-ring-containing AlPO structures. Simultaneously, we compare our method with several classical feature selection methods. The experimental results show that the proposed model exhibits higher predictive accuracy with less synthetic factors. The results also provide an important guidance for the rational design and synthesis of microporous materials. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3019774 Exemplaires
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Titre : Quantification of microcapsules deposited in cotton fabrics before and after abrasion using fluorescence microscopy Type de document : texte imprimé Auteurs : Ruben Mercadé-Prieto, Auteur ; Xuemiao Pan, Auteur ; Angel Fernandez-Gonzalez, Auteur Année de publication : 2012 Article en page(s) : pp. 16741-16749 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Fluorescence Abrasion Microcapsule Résumé : Perfume microcapsules for laundry applications are extensively used in home and consumer care products. Capsules have to bind into the fabric during washing and survive the rinsing and drying steps until the desired moment of rupture, usually when in contact with the skin. In order to assess the performance of the microcapsules in the different steps, quantification methods are required. It is reported here the first methodology, using fluorescence microscopy, whereby the number and size of fluorescent microcapsules is individually determined in large fabric areas using image analysis. The performance of fluorescent melamine-formaldehyde perfume microcapsules of two different sizes under abrasion is studied using smooth and rough surfaces, under dry and wet conditions. Survival profiles are obtained with the number of abrasion passes, allowing for characterizing the performance of microcapsules under different conditions. In addition to quantification, fluorescence and optical microscopy allow for identifying where are the capsules deposited in the fabric, as well as which are the safest zones that allow microcapsules to survive extensive abrasion. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755639
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16741-16749[article] Quantification of microcapsules deposited in cotton fabrics before and after abrasion using fluorescence microscopy [texte imprimé] / Ruben Mercadé-Prieto, Auteur ; Xuemiao Pan, Auteur ; Angel Fernandez-Gonzalez, Auteur . - 2012 . - pp. 16741-16749.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16741-16749
Mots-clés : Fluorescence Abrasion Microcapsule Résumé : Perfume microcapsules for laundry applications are extensively used in home and consumer care products. Capsules have to bind into the fabric during washing and survive the rinsing and drying steps until the desired moment of rupture, usually when in contact with the skin. In order to assess the performance of the microcapsules in the different steps, quantification methods are required. It is reported here the first methodology, using fluorescence microscopy, whereby the number and size of fluorescent microcapsules is individually determined in large fabric areas using image analysis. The performance of fluorescent melamine-formaldehyde perfume microcapsules of two different sizes under abrasion is studied using smooth and rough surfaces, under dry and wet conditions. Survival profiles are obtained with the number of abrasion passes, allowing for characterizing the performance of microcapsules under different conditions. In addition to quantification, fluorescence and optical microscopy allow for identifying where are the capsules deposited in the fabric, as well as which are the safest zones that allow microcapsules to survive extensive abrasion. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26755639 Exemplaires
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Titre : Molecular geometry and melting point related properties Type de document : texte imprimé Auteurs : Bo Lian, Auteur ; Samuel H. Yalkowsky, Auteur Année de publication : 2012 Article en page(s) : pp. 16750–16754 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Molecular geometry Résumé : Melting point and melting-related properties are important in many fields of research. However, they are relatively hard to predict. In this study, an intuitive and simple model, which integrates both additive group contribution values and nonadditive molecular geometric descriptors, has been developed for the estimation of the total enthalpy and entropy of melting as well as the melting point. This model is evaluated using the available reported values of 557 structurally diverse compounds from various molecular shape families. The predicted values are in good agreement with the experimental values of all 3 properties studied. The average absolute errors for the estimation of enthalpy and entropy of melting are 1.80 kJ/mol, 7.09 J/K mol, respectively. The average absolute error for predicting the melting point is 23.14 K, which is much less than that of the well-known EPI Suite program (60.29 K). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302574y
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16750–16754[article] Molecular geometry and melting point related properties [texte imprimé] / Bo Lian, Auteur ; Samuel H. Yalkowsky, Auteur . - 2012 . - pp. 16750–16754.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16750–16754
Mots-clés : Molecular geometry Résumé : Melting point and melting-related properties are important in many fields of research. However, they are relatively hard to predict. In this study, an intuitive and simple model, which integrates both additive group contribution values and nonadditive molecular geometric descriptors, has been developed for the estimation of the total enthalpy and entropy of melting as well as the melting point. This model is evaluated using the available reported values of 557 structurally diverse compounds from various molecular shape families. The predicted values are in good agreement with the experimental values of all 3 properties studied. The average absolute errors for the estimation of enthalpy and entropy of melting are 1.80 kJ/mol, 7.09 J/K mol, respectively. The average absolute error for predicting the melting point is 23.14 K, which is much less than that of the well-known EPI Suite program (60.29 K). ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302574y Exemplaires
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Titre : Wall retardation effects on flow and drag phenomena of confined spherical particles in shear-thickening fluids Type de document : texte imprimé Auteurs : C. Rajasekhar Reddy, Auteur ; Nanda Kishore, Auteur Année de publication : 2012 Article en page(s) : pp.16755–16762 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Spherical particles Résumé : In this work, effects of the wall retardation, Reynolds number, and shear-thickening viscosity behavior of fluids on flow and drag phenomena of confined spherical particles are presented. The governing mass and momentum conservation equations are solved using computational fluid dynamics-based commercial software. The numerical solver is thoroughly validated by comparing present results with existing literature for the case of unconfined spheres in Newtonian and shear-thickening fluids. Extensive new results were presented in the following range of conditions: Reynolds number, Re, 1–100; wall factor, λ, 2–5; and power-law index, n, 1–1.8. The wall factor (λ) is defined as the ratio between the tube diameter and the particle diameter. The severity of wall retardation effects increases with increasing power-law index. For fixed values of the Reynolds number, the recirculation wake length decreases with decreasing wall factor and/or increasing power-law index. For n = 1.8, the wall retardation effects are very strong so that for λ = 2, there is no recirculation wake behind confined sphere even at Re = 100. Furthermore, regardless of values of the Reynolds number, the total drag coefficient increases with increasing power-law index and/or decreasing wall factor. The effect of the Reynolds number on the ratio between pressure and friction drag coefficients decreases with increasing power-law index and/or increasing wall factor. Finally, on the basis of present numerical results, a correlation is developed for the total drag coefficient of confined spherical particles settling in shear-thickening fluids. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302707s
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp.16755–16762[article] Wall retardation effects on flow and drag phenomena of confined spherical particles in shear-thickening fluids [texte imprimé] / C. Rajasekhar Reddy, Auteur ; Nanda Kishore, Auteur . - 2012 . - pp.16755–16762.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp.16755–16762
Mots-clés : Spherical particles Résumé : In this work, effects of the wall retardation, Reynolds number, and shear-thickening viscosity behavior of fluids on flow and drag phenomena of confined spherical particles are presented. The governing mass and momentum conservation equations are solved using computational fluid dynamics-based commercial software. The numerical solver is thoroughly validated by comparing present results with existing literature for the case of unconfined spheres in Newtonian and shear-thickening fluids. Extensive new results were presented in the following range of conditions: Reynolds number, Re, 1–100; wall factor, λ, 2–5; and power-law index, n, 1–1.8. The wall factor (λ) is defined as the ratio between the tube diameter and the particle diameter. The severity of wall retardation effects increases with increasing power-law index. For fixed values of the Reynolds number, the recirculation wake length decreases with decreasing wall factor and/or increasing power-law index. For n = 1.8, the wall retardation effects are very strong so that for λ = 2, there is no recirculation wake behind confined sphere even at Re = 100. Furthermore, regardless of values of the Reynolds number, the total drag coefficient increases with increasing power-law index and/or decreasing wall factor. The effect of the Reynolds number on the ratio between pressure and friction drag coefficients decreases with increasing power-law index and/or increasing wall factor. Finally, on the basis of present numerical results, a correlation is developed for the total drag coefficient of confined spherical particles settling in shear-thickening fluids. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302707s Exemplaires
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Titre : Experimental and numerical study of the flow field and temperature field for a large - scale radiant syngas cooler Type de document : texte imprimé Auteurs : Jianjun Ni, Auteur ; Guangsuo Yu, Auteur ; Qinghua Guo, Auteur Année de publication : 2012 Article en page(s) : pp.4452–4461 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Gas Temperature Résumé : Experimental and numerical studies on the gas-particle flow field and temperature field in the industrial-scale radiant syngas cooler (RSC) have been carried out. The bench-scale cold model experiment was presented for measuring the gas flow field in the RSC. The accuracy and performance of four turbulent flow models were evaluated according to the comparison of predicted results with experimental results. The ash particle trajectories were predicted by the stochastic Lagrangian model and the interaction between the gas and particle phase was also considered by two-way coupling method. A discrete ordinate model (DOM) was used for solving the radiative heat transfer equation when the radiative properties were calculated by weighted-sum-of-gray-gases model (WSGGM). The Ranz−Marshall correlation for the Nusselt number was used to account for convection heat-transfer between the gas phase and the particle phase. The ash particle radiative heat transfer was also considered. The physical properties of gas mixtures were calculated by the mass-weighted-mixing law. The results indicate that the inlet jet flow intensity is dependent on the inlet diameter, but the length of the jet is independent of the inlet diameter. The thickness of the deposition on the membrane wall has great influence on the heat-transfer. The average temperature profiles of particle are higher than gas in the inner cylinder, and it is inversed in the annular. Furthermore, the results show that particles sizes smaller than 580 μm will be entrained into the annular, but the particle size between 400 and 580 μm cannot be entrained out. And the escaping particle’s temperature is lower than the critical temperature when the deposition thickness is 0.2 mm. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100014r
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp.4452–4461[article] Experimental and numerical study of the flow field and temperature field for a large - scale radiant syngas cooler [texte imprimé] / Jianjun Ni, Auteur ; Guangsuo Yu, Auteur ; Qinghua Guo, Auteur . - 2012 . - pp.4452–4461.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp.4452–4461
Mots-clés : Gas Temperature Résumé : Experimental and numerical studies on the gas-particle flow field and temperature field in the industrial-scale radiant syngas cooler (RSC) have been carried out. The bench-scale cold model experiment was presented for measuring the gas flow field in the RSC. The accuracy and performance of four turbulent flow models were evaluated according to the comparison of predicted results with experimental results. The ash particle trajectories were predicted by the stochastic Lagrangian model and the interaction between the gas and particle phase was also considered by two-way coupling method. A discrete ordinate model (DOM) was used for solving the radiative heat transfer equation when the radiative properties were calculated by weighted-sum-of-gray-gases model (WSGGM). The Ranz−Marshall correlation for the Nusselt number was used to account for convection heat-transfer between the gas phase and the particle phase. The ash particle radiative heat transfer was also considered. The physical properties of gas mixtures were calculated by the mass-weighted-mixing law. The results indicate that the inlet jet flow intensity is dependent on the inlet diameter, but the length of the jet is independent of the inlet diameter. The thickness of the deposition on the membrane wall has great influence on the heat-transfer. The average temperature profiles of particle are higher than gas in the inner cylinder, and it is inversed in the annular. Furthermore, the results show that particles sizes smaller than 580 μm will be entrained into the annular, but the particle size between 400 and 580 μm cannot be entrained out. And the escaping particle’s temperature is lower than the critical temperature when the deposition thickness is 0.2 mm. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100014r Exemplaires
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Titre : Additional pilot plant measurements with incorporation of reflux for the fractionation of wax derivatives with supercritical propane Type de document : texte imprimé Auteurs : Cara E. Schwarz, Auteur ; Izak Nieuwoudt, Auteur ; Johannes. H. Knoetze, Auteur Année de publication : 2012 Article en page(s) : pp. 4462–4467 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Wax Derivatives Résumé : Previous studies have shown that supercritical propane can be used to fractionate waxlike alcohol ethoxylates according to the number of ethylene oxide units and that the column temperature, pressure, and solvent to feed ratio influence the selectivity and overheads to feed ratio. Additional pilot plant experiments were conducted to obtain the effect of various process variables. The effect of reflux and the degree thereof as well as the combined influence of the column temperature, the column pressure, the solvent to feed ratio, and the use of reflux were investigated to qualitatively determine how the optimum operating conditions should be selected. To obtain a higher selectivity, lower temperatures and pressures should be used. Furthermore, the solvent to feed ratio as well as the use of reflux can be varied to optimize the separation according to the desired ethylene oxide fractionation. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900397t
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 4462–4467[article] Additional pilot plant measurements with incorporation of reflux for the fractionation of wax derivatives with supercritical propane [texte imprimé] / Cara E. Schwarz, Auteur ; Izak Nieuwoudt, Auteur ; Johannes. H. Knoetze, Auteur . - 2012 . - pp. 4462–4467.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 4462–4467
Mots-clés : Wax Derivatives Résumé : Previous studies have shown that supercritical propane can be used to fractionate waxlike alcohol ethoxylates according to the number of ethylene oxide units and that the column temperature, pressure, and solvent to feed ratio influence the selectivity and overheads to feed ratio. Additional pilot plant experiments were conducted to obtain the effect of various process variables. The effect of reflux and the degree thereof as well as the combined influence of the column temperature, the column pressure, the solvent to feed ratio, and the use of reflux were investigated to qualitatively determine how the optimum operating conditions should be selected. To obtain a higher selectivity, lower temperatures and pressures should be used. Furthermore, the solvent to feed ratio as well as the use of reflux can be varied to optimize the separation according to the desired ethylene oxide fractionation. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900397t Exemplaires
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Titre : Comments on dynamics of flow structures and transport phenomena—part 1. : experimental and numerical techniques for Identification and energy control of flow structures Type de document : texte imprimé Auteurs : Ivan Fort, Auteur Année de publication : 2012 Article en page(s) : pp. 4468–4470 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Dynamics Transport Phenomena Energy Flow ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017447
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 4468–4470[article] Comments on dynamics of flow structures and transport phenomena—part 1. : experimental and numerical techniques for Identification and energy control of flow structures [texte imprimé] / Ivan Fort, Auteur . - 2012 . - pp. 4468–4470.
Industrial chemistry
Langues : Anglais (eng)
in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 4468–4470
Mots-clés : Dynamics Transport Phenomena Energy Flow ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9017447 Exemplaires
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