Documents disponibles écrits par cet auteur

Alkylation of xylenes with isopropyl alcohol over acidic clay supported catalysts / Ganapati D. Yadav in Industrial & engineering chemistry research, Vol. 48 N° 21 (Novembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 21 (Novembre 2009) . - pp. 9383–9393 Titre : Alkylation of xylenes with isopropyl alcohol over acidic clay supported catalysts : efficacy of 20% w/w Cs2.5H0.5PW12O40/K-10 clay Type de document : texte imprimé Auteurs : Ganapati D. Yadav, Auteur ; Shashikant B. Kamble, Auteur Année de publication : 2010 Article en page(s) : pp. 9383–9393 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Xylenes  Alkylation  Isopropyl  alcohol Résumé : The alkylation of xylenes with propylene or isopropyl alcohol (IPA) over solid acid catalysts results in the formation of isopropyl xylenes (dimethyl cumenes). However, the use of propylene as an alkylating agent at very high temperatures leads to coke formation, which results in deactivation of the catalyst. The present work covers evaluation of acidic clay-supported catalysts and sulfated zirconia. A variety of solid acid catalysts such as K-10 clay, sulfated zirconia, Filtrol-24, 20% w/w dodecatungstophosphoric acid (H3PW12O40, DTP) supported on K-10 clay, and 20% w/w cesium-substituted dodecatungstophosphoric acid (Cs2.5H0.5PW12O40, Cs-DTP) supported on K-10 clay under much milder conditions. The best catalyst to achieve maximum conversion and selectivity was determined to be 20% w/w Cs-DTP/K-10 clay. The reactions were conducted in the liquid phase at relatively low reaction temperatures (160−190 °C). The reaction was performed without using any solvent, and the process subscribes to the principles of green chemistry. The catalytic activity has the following order: 20% w/w Cs-DTP/K-10 clay (most active) > 20% w/w DTP/K-10 clay > Filtrol-24 > sulfated zirconia > K-10 clay (least active). The desired product could be efficiently obtained, with selectivities up to 95% at an isopropanol conversion of 98% after 2 h over 20% w/w Cs-DTP/K-10 clay. This process can be a replacement for the existing processes that are based on zeolites, where high temperature and pressure are required. A systematic investigation of the effects of various operating parameters was accomplished and a mathematical model is developed to describe the reaction pathway and validated against experimental results. An overall second-order kinetic equation was used to fit the data, under the assumption that all the species are weakly adsorbed on the catalytic sites. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800737v [article] Alkylation of xylenes with isopropyl alcohol over acidic clay supported catalysts : efficacy of 20% w/w Cs2.5H0.5PW12O40/K-10 clay [texte imprimé] / Ganapati D. Yadav, Auteur ; Shashikant B. Kamble, Auteur . - 2010 . - pp. 9383–9393. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 21 (Novembre 2009) . - pp. 9383–9393 Mots-clés : Xylenes  Alkylation  Isopropyl  alcohol Résumé : The alkylation of xylenes with propylene or isopropyl alcohol (IPA) over solid acid catalysts results in the formation of isopropyl xylenes (dimethyl cumenes). However, the use of propylene as an alkylating agent at very high temperatures leads to coke formation, which results in deactivation of the catalyst. The present work covers evaluation of acidic clay-supported catalysts and sulfated zirconia. A variety of solid acid catalysts such as K-10 clay, sulfated zirconia, Filtrol-24, 20% w/w dodecatungstophosphoric acid (H3PW12O40, DTP) supported on K-10 clay, and 20% w/w cesium-substituted dodecatungstophosphoric acid (Cs2.5H0.5PW12O40, Cs-DTP) supported on K-10 clay under much milder conditions. The best catalyst to achieve maximum conversion and selectivity was determined to be 20% w/w Cs-DTP/K-10 clay. The reactions were conducted in the liquid phase at relatively low reaction temperatures (160−190 °C). The reaction was performed without using any solvent, and the process subscribes to the principles of green chemistry. The catalytic activity has the following order: 20% w/w Cs-DTP/K-10 clay (most active) > 20% w/w DTP/K-10 clay > Filtrol-24 > sulfated zirconia > K-10 clay (least active). The desired product could be efficiently obtained, with selectivities up to 95% at an isopropanol conversion of 98% after 2 h over 20% w/w Cs-DTP/K-10 clay. This process can be a replacement for the existing processes that are based on zeolites, where high temperature and pressure are required. A systematic investigation of the effects of various operating parameters was accomplished and a mathematical model is developed to describe the reaction pathway and validated against experimental results. An overall second-order kinetic equation was used to fit the data, under the assumption that all the species are weakly adsorbed on the catalytic sites. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800737v

Ionic liquid as catalyst for solid-Liquid Phase transfer catalyzed synthesis of p-Nitrodiphenyl ether / Ganapati D. Yadav in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9081–9089 Titre : Ionic liquid as catalyst for solid-Liquid Phase transfer catalyzed synthesis of p-Nitrodiphenyl ether Type de document : texte imprimé Auteurs : Ganapati D. Yadav, Auteur ; Bhavana G. Motirale, Auteur Année de publication : 2009 Article en page(s) : p. 9081–9089 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Synthesis  of  p-Nitrodiphenyl  Ethe Résumé : The novelties of solid−liquid phase transfer catalyzed synthesis of p-nitrodiphenyl ether from p-nitrochlorobenzene and potassium phenoxide were studied in detail with ionic liquids as phase transfer catalysts among others. Tetradecyl(trihexyl)phosphonium bromide was found to be the best catalyst leading to 100% selectivity toward the desired product p-nitrodiphenyl ether. Ionic liquids offer excellent conversions and selectivity, stability at high temperatures, and reusability in this reaction. A mathematical model was developed to study the kinetics of the reaction and used to extract both the rate constant and ion-exchange equilibrium constant. The contribution of the uncatalyzed reaction was also considered in this model. The activation energy and Gibb’s free energy for a combined ion exchange were also calculated. Microwave irradiation was also employed as an effective alternative to conventional heating. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800340j [article] Ionic liquid as catalyst for solid-Liquid Phase transfer catalyzed synthesis of p-Nitrodiphenyl ether [texte imprimé] / Ganapati D. Yadav, Auteur ; Bhavana G. Motirale, Auteur . - 2009 . - p. 9081–9089. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9081–9089 Mots-clés : Synthesis  of  p-Nitrodiphenyl  Ethe Résumé : The novelties of solid−liquid phase transfer catalyzed synthesis of p-nitrodiphenyl ether from p-nitrochlorobenzene and potassium phenoxide were studied in detail with ionic liquids as phase transfer catalysts among others. Tetradecyl(trihexyl)phosphonium bromide was found to be the best catalyst leading to 100% selectivity toward the desired product p-nitrodiphenyl ether. Ionic liquids offer excellent conversions and selectivity, stability at high temperatures, and reusability in this reaction. A mathematical model was developed to study the kinetics of the reaction and used to extract both the rate constant and ion-exchange equilibrium constant. The contribution of the uncatalyzed reaction was also considered in this model. The activation energy and Gibb’s free energy for a combined ion exchange were also calculated. Microwave irradiation was also employed as an effective alternative to conventional heating. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800340j

Kinetic and mechanistic investigation of microwave-assisted lipase catalyzed synthesis of citronellyl acetate / Ganapati D. Yadav in Industrial & engineering chemistry research, Vol. 48 N° 17 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 17 (Septembre 2009) . - pp. 7915–7922 Titre : Kinetic and mechanistic investigation of microwave-assisted lipase catalyzed synthesis of citronellyl acetate Type de document : texte imprimé Auteurs : Ganapati D. Yadav, Auteur ; Indrakant V. Borkar, Auteur Année de publication : 2009 Article en page(s) : pp. 7915–7922 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Citronellyl  acetate  Chemical  catalysis  Biocatalysis Résumé : Citronellyl acetate (also known as citronellol acetate) is an important perfumery chemical which can be produced both by chemical catalysis and by biocatalysis. In the current work, Novozym 435 (Candida antarctica lipase B immobilized on polyacrylic resin) was employed to synthesize citronellol acetate directly from citronellol and vinyl acetate under the influence of microwave irradiation vis-à-vis conventional heating. The effects of various parameters affecting the conversion and initial rates of transesterification were studied to deduce the kinetics and mechanism. The enzyme inhibition was studied in conjunction with both modes of heating. Under microwave irradiation, there was an increase in lipase activity due to enhanced collision of molecules, which can in turn be attributed to an increase in the entropy of the system. The synergistic effect of reaction media and microwaves on lipase activity was analyzed. The enzyme is inhibited by alcohol, which is reduced significantly by microwaves. The analysis of the initial rate data and progress curve data showed that the reaction obeys the ping-pong bi−bi mechanism with inhibition by citronellol and vinyl acetate. The experimental and theoretical values match very well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800591c [article] Kinetic and mechanistic investigation of microwave-assisted lipase catalyzed synthesis of citronellyl acetate [texte imprimé] / Ganapati D. Yadav, Auteur ; Indrakant V. Borkar, Auteur . - 2009 . - pp. 7915–7922. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 17 (Septembre 2009) . - pp. 7915–7922 Mots-clés : Citronellyl  acetate  Chemical  catalysis  Biocatalysis Résumé : Citronellyl acetate (also known as citronellol acetate) is an important perfumery chemical which can be produced both by chemical catalysis and by biocatalysis. In the current work, Novozym 435 (Candida antarctica lipase B immobilized on polyacrylic resin) was employed to synthesize citronellol acetate directly from citronellol and vinyl acetate under the influence of microwave irradiation vis-à-vis conventional heating. The effects of various parameters affecting the conversion and initial rates of transesterification were studied to deduce the kinetics and mechanism. The enzyme inhibition was studied in conjunction with both modes of heating. Under microwave irradiation, there was an increase in lipase activity due to enhanced collision of molecules, which can in turn be attributed to an increase in the entropy of the system. The synergistic effect of reaction media and microwaves on lipase activity was analyzed. The enzyme is inhibited by alcohol, which is reduced significantly by microwaves. The analysis of the initial rate data and progress curve data showed that the reaction obeys the ping-pong bi−bi mechanism with inhibition by citronellol and vinyl acetate. The experimental and theoretical values match very well. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800591c

Kinetic modeling and statistical optimization of lipase catalyzed enantioselective resolution of (R,S) - 2 - pentanol / Jyoti B. Sontakke in Industrial & engineering chemistry research, Vol. 50 N° 23 (Décembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12975-12983 Titre : Kinetic modeling and statistical optimization of lipase catalyzed enantioselective resolution of (R,S) - 2 - pentanol Type de document : texte imprimé Auteurs : Jyoti B. Sontakke, Auteur ; Ganapati D. Yadav, Auteur Année de publication : 2012 Article en page(s) : pp. 12975-12983 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling  Enzymatic  catalysis  Optimization  Kinetic  model Résumé : S-2-pentanol is a chiral intermediate in the synthesis of several potential antialzheimer's drugs that inhibit β-amyloid peptide release or its synthesis. The present work focuses on the kinetic resolution of (R,S)-2-pentanol using vinyl acetate as an acyl donor. Effects of various parameters were studied to deduce the kinetics and mechanism of the reaction. Novozyme 435 was found to be the most efficient catalyst among different catalysts studied Response Surface methodology and Box-Behnken design were employed to evaluate the effect of process parameters such as speed of agitation, enzyme loading, temperature and acyl donor/ alcohol molar ratio on conversion, enantiomeric excess, enantioselectivity and initial rate. Initial rate data and progress curve data were used to arrive at a suitable model. Ping-pong bi-bi mechanism with 2-pentanol inhibition was found to describe the kinetics of the reaction. The kinetic parameters evaluated from initial rate data were used to simulate the experimental results. There was a very good agreement between theory and experiment. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267454 [article] Kinetic modeling and statistical optimization of lipase catalyzed enantioselective resolution of (R,S) - 2 - pentanol [texte imprimé] / Jyoti B. Sontakke, Auteur ; Ganapati D. Yadav, Auteur . - 2012 . - pp. 12975-12983. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12975-12983 Mots-clés : Modeling  Enzymatic  catalysis  Optimization  Kinetic  model Résumé : S-2-pentanol is a chiral intermediate in the synthesis of several potential antialzheimer's drugs that inhibit β-amyloid peptide release or its synthesis. The present work focuses on the kinetic resolution of (R,S)-2-pentanol using vinyl acetate as an acyl donor. Effects of various parameters were studied to deduce the kinetics and mechanism of the reaction. Novozyme 435 was found to be the most efficient catalyst among different catalysts studied Response Surface methodology and Box-Behnken design were employed to evaluate the effect of process parameters such as speed of agitation, enzyme loading, temperature and acyl donor/ alcohol molar ratio on conversion, enantiomeric excess, enantioselectivity and initial rate. Initial rate data and progress curve data were used to arrive at a suitable model. Ping-pong bi-bi mechanism with 2-pentanol inhibition was found to describe the kinetics of the reaction. The kinetic parameters evaluated from initial rate data were used to simulate the experimental results. There was a very good agreement between theory and experiment. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25267454

Kinetic modeling of immobilized lipase catalysis in synthesis of n-butyl levulinate / Ganapati D. Yadav in Industrial & engineering chemistry research, Vol. 47 N°10 (Mai 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°10 (Mai 2008) . - p. 3358–3363 Titre : Kinetic modeling of immobilized lipase catalysis in synthesis of n-butyl levulinate Type de document : texte imprimé Auteurs : Ganapati D. Yadav, Auteur Année de publication : 2008 Article en page(s) : p. 3358–3363 Note générale : Bibliogr. p. 3363 Langues : Anglais (eng) Mots-clés : n-Butyl  levulinate  --  esterification;  Immobilized  lipases Résumé : n-Butyl levulinate is used as an important intermediate having diverse applications. The present work focuses on the synthesis of n-butyl levulinate by esterification of levulinic acid with n-butanol by using immobilized lipases. Novozym 435 (Candida antarctica lipase) was found to be the most efficient catalyst, and tetra-butyl methyl ether was the best solvent. Effects of various parameters were studied to analyze the kinetics and mechanism of the lipase action. Ping-pong bi−bi mechanism with n-butanol substrate inhibition was found to describe the kinetics of the reaction. The kinetic parameters evaluated from initial rate data were used to simulate the experimental results. There was a very good agreement between theory and experiment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800193f [article] Kinetic modeling of immobilized lipase catalysis in synthesis of n-butyl levulinate [texte imprimé] / Ganapati D. Yadav, Auteur . - 2008 . - p. 3358–3363. Bibliogr. p. 3363 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°10 (Mai 2008) . - p. 3358–3363 Mots-clés : n-Butyl  levulinate  --  esterification;  Immobilized  lipases Résumé : n-Butyl levulinate is used as an important intermediate having diverse applications. The present work focuses on the synthesis of n-butyl levulinate by esterification of levulinic acid with n-butanol by using immobilized lipases. Novozym 435 (Candida antarctica lipase) was found to be the most efficient catalyst, and tetra-butyl methyl ether was the best solvent. Effects of various parameters were studied to analyze the kinetics and mechanism of the lipase action. Ping-pong bi−bi mechanism with n-butanol substrate inhibition was found to describe the kinetics of the reaction. The kinetic parameters evaluated from initial rate data were used to simulate the experimental results. There was a very good agreement between theory and experiment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800193f

Novelties of solid-Liquid phase transfer catalyzed synthesis of triclosan from potassium 2,4-Dichlorophenolate and 2,5-Dichlorophenol / Ganapati D. Yadav in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

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Prediction of liquid – liquid equilibria for biofuel applications by quantum chemical calculations using the cosmo - SAC method / Mitesh R. Shah in Industrial & engineering chemistry research, Vol. 50 N° 23 (Décembre 2011) 

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Transesterification of edible and nonedible vegetable oils with alcohols over heteropolyacids supported on acid-treated clay / Vijay V. Bokade in Industrial & engineering chemistry research, Vol. 48 N° 21 (Novembre 2009) 

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UDCaT-5: a novel mesoporous superacid catalyst in the selective synthesis of linear phenyldodecanes by the alkylation of benzene with 1-dodecene / Ganapati D. Yadav in Industrial & engineering chemistry research, Vol. 48 N° 24 (Décembre 2009) 

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UDCaT-5 / Ganapati D. Yadav in Industrial & engineering chemistry research, Vol. 48 N° 24 (Décembre 2009) 

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