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Photocatalytic degradation of nitrobenzene in an aqueous system by transition-metal-exchanged ETS-10 zeolites / Praveen K. Surolia in Industrial & engineering chemistry research, Vol. 49 N° 8 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp 3961–3966 Titre : Photocatalytic degradation of nitrobenzene in an aqueous system by transition-metal-exchanged ETS-10 zeolites Type de document : texte imprimé Auteurs : Praveen K. Surolia, Auteur ; Rajesh J. Tayade, Auteur ; Raksh V. Jasra, Auteur Année de publication : 2010 Article en page(s) : pp 3961–3966 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Photocatalytic  Nitrobenzene  Nitrobenzene  Metal-Exchanged  Zeolites Résumé : Engelhard titanosilicate ETS-10 was synthesized using Degussa P25 as the titanium source. Metal-exchanged microporous titanium silicate M−ETS-10 (M = Fe, Co, Ni, Cu, and Ag) samples were prepared by ion exchange with respective metal salt solutions. The synthesized samples were characterized by powder X-ray diffraction, BET surface area, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and UV−vis diffuse reflectance measurements (DRS). The photocatalytic activity of these samples was investigated for the decomposition of nitrobenzene (NB). The pristine ETS-10 and transition-metal-ion-exchanged ETS-10 samples were found to be active photocatalysts that can decompose nitrobenzene under UV irradiation. Results demonstrated that silver-ion-exchanged ETS-10 shows the highest photocatalytic activity for degradation and mineralization of nitrobenzene. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901603k [article] Photocatalytic degradation of nitrobenzene in an aqueous system by transition-metal-exchanged ETS-10 zeolites [texte imprimé] / Praveen K. Surolia, Auteur ; Rajesh J. Tayade, Auteur ; Raksh V. Jasra, Auteur . - 2010 . - pp 3961–3966. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp 3961–3966 Mots-clés : Photocatalytic  Nitrobenzene  Nitrobenzene  Metal-Exchanged  Zeolites Résumé : Engelhard titanosilicate ETS-10 was synthesized using Degussa P25 as the titanium source. Metal-exchanged microporous titanium silicate M−ETS-10 (M = Fe, Co, Ni, Cu, and Ag) samples were prepared by ion exchange with respective metal salt solutions. The synthesized samples were characterized by powder X-ray diffraction, BET surface area, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and UV−vis diffuse reflectance measurements (DRS). The photocatalytic activity of these samples was investigated for the decomposition of nitrobenzene (NB). The pristine ETS-10 and transition-metal-ion-exchanged ETS-10 samples were found to be active photocatalysts that can decompose nitrobenzene under UV irradiation. Results demonstrated that silver-ion-exchanged ETS-10 shows the highest photocatalytic activity for degradation and mineralization of nitrobenzene. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901603k

Rhodium metal complex and hydrotalcite based environmentally friendly catalyst system for the selective synthesis of C8-aldehydes from propylene / Vivek K. Srivastava in Industrial & engineering chemistry research, Vol. 47 n°11 (Juin 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°11 (Juin 2008) . - p. 3795–3803 Titre : Rhodium metal complex and hydrotalcite based environmentally friendly catalyst system for the selective synthesis of C8-aldehydes from propylene Type de document : texte imprimé Auteurs : Vivek K. Srivastava, Auteur ; Sumeet K. Sharma, Auteur ; Ram S. Shukla, Auteur ; Raksh V. Jasra, Auteur Année de publication : 2008 Article en page(s) : p. 3795–3803 Note générale : Bibliogr. p. 3802-3803 Langues : Anglais (eng) Mots-clés : Rhodium  complex;  Catalytic  activity;  Kinetic  profiles;  Reaction  rates Résumé : Catalytic activity of a novel catalyst [HFN + HT] containing a rhodium complex, HRh(CO)(PPh3)3 [HFN], and a solid base, hydrotalcite Mg1-xAlx(OH2)x+(CO32−)x/n·mH2O [HT], was evaluated for carrying out hydroformylation, aldol condensation, and hydrogenation in a single pot for the synthesis of C8-aldehydes, 2-ethylhexenal and 2-ethylhexanal, from propylene. In typical catalytic experiments conducted in a high-pressure reactor of 100 mL capacity, the selectivity for the formation of 2-ethylhexanal (54%) was found to be four times more than that of 2-ethylhexenal (13%) at 150 °C with employed partial pressures of propylene, carbon monoxide, and hydrogen at 10, 5, and 15 bar, respectively. Detailed investigations were performed on the effects of various reaction parameters, Mg/Al molar ratio (X) of [HT], amount of [HFN] complex, amount of [HT], and reaction temperature, on the formation of C8-aldehydes from propylene in a single pot. Under the employed reaction conditions, the maximum selectivity for 2-ethylhexanal was observed using hydrotalcite of Mg/Al molar ratio 3.5. Increasing the amounts of both [HFN] complex and [HT] favored the selectivities for the formation of 2-ethylhexanal up to certain amounts, and after that, on further increasing the amounts, the selectivities for the same were decreased. The kinetic profiles for the formation of various products with time and reaction rates were determined. For comparative studies, the kinetic profiles and reaction rates with the commercially employed catalyst, [HFN + KOH], were also determined under identical reaction conditions of [HFN + HT(3.5)], and the selectivity of 2-ethylhexanal was found to be almost identical at 7 h for the both systems. On the basis of experiments and kinetic profiles, reaction pathways are suggested for the formation of C8-aldehydes from propylene in a single pot. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071108r [article] Rhodium metal complex and hydrotalcite based environmentally friendly catalyst system for the selective synthesis of C8-aldehydes from propylene [texte imprimé] / Vivek K. Srivastava, Auteur ; Sumeet K. Sharma, Auteur ; Ram S. Shukla, Auteur ; Raksh V. Jasra, Auteur . - 2008 . - p. 3795–3803. Bibliogr. p. 3802-3803 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°11 (Juin 2008) . - p. 3795–3803 Mots-clés : Rhodium  complex;  Catalytic  activity;  Kinetic  profiles;  Reaction  rates Résumé : Catalytic activity of a novel catalyst [HFN + HT] containing a rhodium complex, HRh(CO)(PPh3)3 [HFN], and a solid base, hydrotalcite Mg1-xAlx(OH2)x+(CO32−)x/n·mH2O [HT], was evaluated for carrying out hydroformylation, aldol condensation, and hydrogenation in a single pot for the synthesis of C8-aldehydes, 2-ethylhexenal and 2-ethylhexanal, from propylene. In typical catalytic experiments conducted in a high-pressure reactor of 100 mL capacity, the selectivity for the formation of 2-ethylhexanal (54%) was found to be four times more than that of 2-ethylhexenal (13%) at 150 °C with employed partial pressures of propylene, carbon monoxide, and hydrogen at 10, 5, and 15 bar, respectively. Detailed investigations were performed on the effects of various reaction parameters, Mg/Al molar ratio (X) of [HT], amount of [HFN] complex, amount of [HT], and reaction temperature, on the formation of C8-aldehydes from propylene in a single pot. Under the employed reaction conditions, the maximum selectivity for 2-ethylhexanal was observed using hydrotalcite of Mg/Al molar ratio 3.5. Increasing the amounts of both [HFN] complex and [HT] favored the selectivities for the formation of 2-ethylhexanal up to certain amounts, and after that, on further increasing the amounts, the selectivities for the same were decreased. The kinetic profiles for the formation of various products with time and reaction rates were determined. For comparative studies, the kinetic profiles and reaction rates with the commercially employed catalyst, [HFN + KOH], were also determined under identical reaction conditions of [HFN + HT(3.5)], and the selectivity of 2-ethylhexanal was found to be almost identical at 7 h for the both systems. On the basis of experiments and kinetic profiles, reaction pathways are suggested for the formation of C8-aldehydes from propylene in a single pot. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071108r

Rhodium supported Hβ zeolite for the hydrogenation of toluene / Kalpesh B. Sidhpuria in Industrial & engineering chemistry research, Vol. 47 n°12 (Juin 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°12 (Juin 2008) . - p. 4034–4042 Titre : Rhodium supported Hβ zeolite for the hydrogenation of toluene Type de document : texte imprimé Auteurs : Kalpesh B. Sidhpuria, Auteur ; Parimal A. Parikh, Auteur ; Pratap Bahadur, Auteur ; Raksh V. Jasra, Auteur Année de publication : 2008 Article en page(s) : p. 4034–4042 Note générale : Bibliogr. p. 4041-4042 Langues : Anglais (eng) Mots-clés : Noble  metal  Rh;  Toluene  --  hydrodearomatization;  Fourier  transform  infrared  spectra;  Chemical  analysis Résumé : Noble metal Rh supported on a large pore high acidic zeolite Hβ has been explored as a hydrodearomatization catalyst. The detail kinetic study of hydrodearomatization of toluene over a 1 wt % Rh/Hβ was done in a continuous-downflow stainless steel catalytic fixed bed reactor at varied space time, toluene feed rate, hydrogen partial pressure, hydrogen to toluene mole ratio, temperature, and in the presence of dibenzothiophene. The time on stream data and reaction order with respect to toluene were measured and was found to be of first order. Fourier transform infrared (FTIR) spectra and chemical analysis of fresh and spent catalyst suggested the presence of surface carbon species and weight percent carbon was found to be 4.43%. It was observed that toluene conversion was increased on increasing H2 partial pressure and H2/feed mole ratio. The conversion is dependent on temperature and shows a well-defined maximum. The decrease of the catalyst activity in the presence of dibenzothiophene is mainly attributed to the adsorption and decomposition of dibenzothiophene (DBT) on the metal sites, which results in a loss of metal surface available for the reaction to take place and a higher coke formation reducing the fraction of acid sites available for toluene hydrodearomatization. A nonlinear semiempirical kinetic model was also developed to have the best fit with 12% error. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001793 [article] Rhodium supported Hβ zeolite for the hydrogenation of toluene [texte imprimé] / Kalpesh B. Sidhpuria, Auteur ; Parimal A. Parikh, Auteur ; Pratap Bahadur, Auteur ; Raksh V. Jasra, Auteur . - 2008 . - p. 4034–4042. Bibliogr. p. 4041-4042 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°12 (Juin 2008) . - p. 4034–4042 Mots-clés : Noble  metal  Rh;  Toluene  --  hydrodearomatization;  Fourier  transform  infrared  spectra;  Chemical  analysis Résumé : Noble metal Rh supported on a large pore high acidic zeolite Hβ has been explored as a hydrodearomatization catalyst. The detail kinetic study of hydrodearomatization of toluene over a 1 wt % Rh/Hβ was done in a continuous-downflow stainless steel catalytic fixed bed reactor at varied space time, toluene feed rate, hydrogen partial pressure, hydrogen to toluene mole ratio, temperature, and in the presence of dibenzothiophene. The time on stream data and reaction order with respect to toluene were measured and was found to be of first order. Fourier transform infrared (FTIR) spectra and chemical analysis of fresh and spent catalyst suggested the presence of surface carbon species and weight percent carbon was found to be 4.43%. It was observed that toluene conversion was increased on increasing H2 partial pressure and H2/feed mole ratio. The conversion is dependent on temperature and shows a well-defined maximum. The decrease of the catalyst activity in the presence of dibenzothiophene is mainly attributed to the adsorption and decomposition of dibenzothiophene (DBT) on the metal sites, which results in a loss of metal surface available for the reaction to take place and a higher coke formation reducing the fraction of acid sites available for toluene hydrodearomatization. A nonlinear semiempirical kinetic model was also developed to have the best fit with 12% error. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001793

Selective adsorption of oxygen over argon in alkaline - earth - metal cation - exchanged zeolite X / Sunil A. Peter in Industrial & engineering chemistry research, Vol. 49 N° 16 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7524–7529 Titre : Selective adsorption of oxygen over argon in alkaline - earth - metal cation - exchanged zeolite X Type de document : texte imprimé Auteurs : Sunil A. Peter, Auteur ; Arun S. Moharir, Auteur ; Raksh V. Jasra, Auteur Année de publication : 2010 Article en page(s) : pp. 7524–7529 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Adsorbed  molecule  Adsorption  behavior  Alkaline  earth  Cation-exchanged  zeolites  Chromatographic  separations  Electrostatic  interactions Résumé : The separation of argon and oxygen from their gaseous mixture by adsorption is challenging because of the closeness of their molecular properties and, hence, adsorption behavior. In the present study, the potential of zeolite X with strontium as the extraframework cation as an oxygen-selective adsorbent for the separation and purification of argon is discussed. Equilibrium adsorption isotherms of oxygen and argon on calcium, strontium, and barium cation-exchanged zeolite X were measured at 288 and 303 K. The equilibrium adsorption capacity and selectivity for oxygen over argon were observed to be higher in zeolite X exchanged with alkaline-earth-metal cations than in NaX. Among these alkaline-earth-metal cation-exchanged zeolite X adsorbents, SrX showed the highest adsorption selectivity, in the range of 2.0 at 50 mmHg to 1.8 at 760 mmHg for oxygen over argon at 303 K. The increased selectivity for oxygen over argon in SrX is discussed in terms of the size, location, and effective partial charges on the extraframework cations present in the zeolite cavity and the subsequent electrostatic interactions between the adsorbed molecules and the extraframework cations. Strontium cation-exchanged zeolite X is also shown to be useful for the chromatographic separation and analysis of argon/oxygen mixtures. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100615e [article] Selective adsorption of oxygen over argon in alkaline - earth - metal cation - exchanged zeolite X [texte imprimé] / Sunil A. Peter, Auteur ; Arun S. Moharir, Auteur ; Raksh V. Jasra, Auteur . - 2010 . - pp. 7524–7529. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7524–7529 Mots-clés : Adsorbed  molecule  Adsorption  behavior  Alkaline  earth  Cation-exchanged  zeolites  Chromatographic  separations  Electrostatic  interactions Résumé : The separation of argon and oxygen from their gaseous mixture by adsorption is challenging because of the closeness of their molecular properties and, hence, adsorption behavior. In the present study, the potential of zeolite X with strontium as the extraframework cation as an oxygen-selective adsorbent for the separation and purification of argon is discussed. Equilibrium adsorption isotherms of oxygen and argon on calcium, strontium, and barium cation-exchanged zeolite X were measured at 288 and 303 K. The equilibrium adsorption capacity and selectivity for oxygen over argon were observed to be higher in zeolite X exchanged with alkaline-earth-metal cations than in NaX. Among these alkaline-earth-metal cation-exchanged zeolite X adsorbents, SrX showed the highest adsorption selectivity, in the range of 2.0 at 50 mmHg to 1.8 at 760 mmHg for oxygen over argon at 303 K. The increased selectivity for oxygen over argon in SrX is discussed in terms of the size, location, and effective partial charges on the extraframework cations present in the zeolite cavity and the subsequent electrostatic interactions between the adsorbed molecules and the extraframework cations. Strontium cation-exchanged zeolite X is also shown to be useful for the chromatographic separation and analysis of argon/oxygen mixtures. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100615e

Sorption of CO, CH4, and N2 in alkali metal ion exchanged zeolite-X / Renjith S. Pillai in Industrial & engineering chemistry research, Vol. 49 N° 12 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5816–5825 Titre : Sorption of CO, CH4, and N2 in alkali metal ion exchanged zeolite-X : grand canonical Monte Carlo simulation and volumetric measurements Type de document : texte imprimé Auteurs : Renjith S. Pillai, Auteur ; Govind Sethia, Auteur ; Raksh V. Jasra, Auteur Année de publication : 2010 Article en page(s) : pp. 5816–5825 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : CO  sorption  CH4  sorptionN2Alkali  metal  ions  Monte  Carlo  simulation Résumé : Sorption of CO, CH4, and N2 in zeolite-X exchanged with different alkali metal ions was studied by volumetric measurements and Grand Canonical Monte Carlo simulation. CO and CH4 sorption is observed to show higher sorption capacity than N2 in all cation exchanged zeolite samples. The adsorption capacity of CO in alkali metal exchanged zeolites is observed to decrease on moving from LiX to CsX, whereas for the methane adsorption capacity varies in reverse order. The isosteric heat of sorption data show stronger interactions of CO and N2 molecules with alkali metal ion exchanged zeolites. The isosteric heat of CH4 show nearly same value (21−24 kJ/mol) for all alkali metal ion exchanged zeolites. Simulation of the CO and N2 sorption in alkali metal zeolite -X clearly shows that the adsorbed CO and N2 molecules are located in proximity to the extra-framework cations in the super cage. Simulated data of adsorption isotherms and heats of adsorption of CO, N2, and CH4 in alkali metal ion exchanged zeolite-X agree reasonably well with the experimental results. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901713m [article] Sorption of CO, CH4, and N2 in alkali metal ion exchanged zeolite-X : grand canonical Monte Carlo simulation and volumetric measurements [texte imprimé] / Renjith S. Pillai, Auteur ; Govind Sethia, Auteur ; Raksh V. Jasra, Auteur . - 2010 . - pp. 5816–5825. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5816–5825 Mots-clés : CO  sorption  CH4  sorptionN2Alkali  metal  ions  Monte  Carlo  simulation Résumé : Sorption of CO, CH4, and N2 in zeolite-X exchanged with different alkali metal ions was studied by volumetric measurements and Grand Canonical Monte Carlo simulation. CO and CH4 sorption is observed to show higher sorption capacity than N2 in all cation exchanged zeolite samples. The adsorption capacity of CO in alkali metal exchanged zeolites is observed to decrease on moving from LiX to CsX, whereas for the methane adsorption capacity varies in reverse order. The isosteric heat of sorption data show stronger interactions of CO and N2 molecules with alkali metal ion exchanged zeolites. The isosteric heat of CH4 show nearly same value (21−24 kJ/mol) for all alkali metal ion exchanged zeolites. Simulation of the CO and N2 sorption in alkali metal zeolite -X clearly shows that the adsorbed CO and N2 molecules are located in proximity to the extra-framework cations in the super cage. Simulated data of adsorption isotherms and heats of adsorption of CO, N2, and CH4 in alkali metal ion exchanged zeolite-X agree reasonably well with the experimental results. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901713m

Synthesis and characterization of Mg-Al-CO3 layered double hydroxide for CO2 adsorption / Ulka Sharma in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

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TiO2 - coated cenospheres as catalysts for photocatalytic degradation of methylene blue, p - nitroaniline, n - decane, and n - tridecane under solar irradiation / Praveen K. Surolia in Industrial & engineering chemistry research, Vol. 49 N° 19 (Octobre 2010) 

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