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Ganapati D Yadav - One of the best experts on this subject based on the ideXlab platform.
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selectivity engineering of cation exchange resins over inorganic solid acids in c alkylation of guaiacol with cyclohexene
Industrial & Engineering Chemistry Research, 2007Co-Authors: Ganapati D Yadav, Ganesh S PathreAbstract:Friedel−Crafts alkylation of guaiacol with cyclohexene gives both C- and O-alkylated products, which are commercially valuable. The C-alkylated products are important intermediates for the production of resins, antioxidants, drugs, dyes, polymer additives, agrochemicals, and antiseptic substances. The objective of the current work was to achieve maximum selectivity for the C-alkylated products, using an active catalyst with minimum separation cost. A variety of eco-friendly solid acid catalysts such as sulfated zirconia, Amberlyst-15, Filtrol-24, cesium-modified dodecatungstophosphoric acid (Cs-DTP) supported over K-10 clay (20% w/w Cs2.5H0.5PW12O40/K-10), and 20% w/w dodecatungstophosphoric acid (DTP)/K-10 clay were screened to study the effect of their nature of acidity on product distribution. Amberlyst-15 was determined to be the best catalyst to achieve maximum selectivity for C-alkylated product at 80 °C. The O-alkylation versus C-alkylation not only was observed to be highly temperature sensitive, ...
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Activities of clays and ion exchange resins in the synthesis of phthalate esters
Clean Technologies and Environmental Policy, 2004Co-Authors: Ganapati D Yadav, M. S. M. Mujeebur RahumanAbstract:Phthalate esters are used as plasticisers, solvents and perfumery compounds. Usually homogenous polluting and corrosive acids are used as catalysts for esterification which leave traces of inorganic impurities in the final product and they also impart coloration. This paper evaluates the activities of acid treated clays and ion exchange resins in the esterification of phthalic anhydride using methanol as the model alcohol. % MathType!Translator!2!1!AMS LaTeX.tdl!TeX -- AMS-LaTeX! % MathType!MTEF!2!1!+- % feaafaart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaeyqaiaab2 % gacaqGIbGaaeyzaiaabkhacaqGSbGaaeyEaiaabohacaqG0bGaaeyl % aiaabodacaqG2aGaaeOpaiaabgeacaqGTbGaaeOyaiaabwgacaqGYb % GaaeiBaiaabMhacaqGZbGaaeiDaiaab2cacaqGXaGaaeynaiaab6da % caqGGaGaaeysaiaab6gacaqGKbGaaeyAaiaab+gacaqGUbGaaeylai % aabgdacaqGZaGaaeimaiaab6dacaqGebGaaeyzaiaabYgacaqGVbGa % aeiEaiaabggacaqGUbGaaeyzaiaabccacaqG+aGaaeOraiaabMgaca % qGSbGaaeOCaiaab+gacaqGSbGaaeylaiaabkdacaqG0aGaaeiiaiaa % boeacaqGSbGaaeyyaiaabMhacaqGGaGaaeOpaiaabUeacaqGTaGaae % ymaiaabcdacaqGGaGaae4qaiaabYgacaqGHbGaaeyEaaaa!72E3! $$ {\text{Amberlyst - 36 > Amberlyst - 15 > Indion - 130 > Deloxane > Filrol - 24 Clay > K - 10 Clay}} $$ The effects of various parameters with Amberlyst-36 were studied to find that the reaction was intrinsically kinetically controlled. It was observed that the catalyst chosen had excellent reusability and was not deactivated. A kinetic model was developed from the experimental data. Phthalate esters of ethanol, n -propanol and n -butanol were also synthesized.
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esterification of maleic acid with ethanol over cation exchange resin catalysts
Reactive & Functional Polymers, 2002Co-Authors: Ganapati D Yadav, Mehul B. ThathagarAbstract:Diethyl maleate is an important intermediate extensively used in the production of latex emulsion polymers, thermoplast and thermoset plastics. The current paper delineates the efficacy of several heterogeneous catalysts, such as Indion-170, Amberlyst-36, Amberlyst-15, Amberlite IRA 120, 20% DTP/K-10 (dodecatungstophosphoric acid supported on K-10 clay) in the esterification of maleic acid with ethanol at reflux. Amongst these Indion-170, Amberlyst-36, Amberlyst-15 were observed to be the most effective. It was observed that the catalyst chosen has excellent reusability and was not deactivated. The effects of various parameters on the rate of reaction demonstrated that the reaction was intrinsically kinetically controlled and there were no intraparticle and interparticle mass transfer limitations. A pseudo-homogeneous kinetic model was developed from the experimental data and activation energy was found to be 14.2 kcal/mol, which also suggested that this reaction was intrinsically kinetically controlled.
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E of maleic acid with ethanol over cation-exchange resin catalysts
2002Co-Authors: Ganapati D Yadav, Mehul B. ThathagarAbstract:Diethyl maleate is an important intermediate extensively used in the production of latex emulsion polymers, thermoplast and thermoset plastics. The current paper delineates the efficacy of several heterogeneous catalysts, such as Indion-170, Amberlyst-36, Amberlyst-15, Amberlite IRA 120, 20% DTP/ K-10 (dodecatungstophosphoric acid supported on K-10 clay) in the esterification of maleic acid with ethanol at reflux. Amongst these Indion-170, Amberlyst-36, Amberlyst-15 were observed to be the most effective. It was observed that the catalyst chosen has excellent reusability and was not deactivated. The effects of various parameters on the rate of reaction demonstrated that the reaction was intrinsically kinetically controlled and there were no intraparticle and interparticle mass transfer limitations. A pseudo-homogeneous kinetic model was developed from the experimental data and activation energy was found to be 14.2 kcal / mol, which also suggested that this reaction was intrinsically kinetically controlled. 2002 Elsevier Science B.V. All rights reserved.
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ion exchange resin catalysis in the synthesis of isopropyl lactate
Reactive & Functional Polymers, 2000Co-Authors: Ganapati D Yadav, H B KulkarniAbstract:Abstract Isopropyl lactate is a very important pharmaceutical intermediate. The current practice is to use homogeneous acids as catalysts. These catalysts are hazardous and disposal of liquid acid effluents poses problems. The separation of the liquid catalyst and its reuse is another problem. The current paper deals with the application of heterogeneous catalysts Indion-130, Ambelyst-36, Amberlyst-15, Amberlite-120, Dowex 50W, Filtrol-44, 20% DTPA/K-10 (dodecatungstophosphoric acid supported on K-10 clay) and 20% DTPA/Filtrol-44 (dodecatungstophosphoric acid supported on Filtrol-44 clay). Amongst these Amberlyst-36, Amberlyst-15 and Indion-130 were observed to be most effective. A theoretical kinetic model was developed for evaluation of this slurry reaction. The effects of various parameters on the rate of reaction were evaluated. The reaction was found to be intrinsically kinetically controlled and there were no intraparticle as well as interparticle mass transfer limitations on the rate of reaction.
Gang Yu - One of the best experts on this subject based on the ideXlab platform.
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efficient carbon based solid acid catalysts for the esterification of oleic acid
Catalysis Communications, 2011Co-Authors: Liang Geng, Yu Wang, Gang YuAbstract:Abstract A series of carbon-based solid acid catalysts was prepared by the sulfonation of mesoporous carbon substrates with thin pore walls, and catalytic activity for the esterification of oleic acid with methanol was tested. The highest turnover frequency (TOF) observed was 78 h − 1 , five times that of Amberlyst-15. The high catalytic activity may be attributed to the good dispersion of the catalysts in methanol. Catalysts with improved dispersion were obtained by a modified preparation, after which the highest TOF observed was 109 h − 1 , seven times that of Amberlyst-15.
Nalan Ozbay - One of the best experts on this subject based on the ideXlab platform.
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Activity Comparison of Different Solid Acid Catalysts in Etherification of Glycerol with tert-Butyl Alcohol in Flow and Batch Reactors
Topics in Catalysis, 2013Co-Authors: Nalan Ozbay, Nuray Oktar, Gulsen Dogu, Timur DoguAbstract:In the presented work, etherification of glycerol with TBA was investigated in a continuous flow and also in a batch reactor using nine different commercial solid acid catalysts, namely Amberlyst-15, Amberlyst-36, Amberlyst-35, Amberlyst-16, Relite EXC8D, Lewatit K2629, H-Beta, H-Mordenite and Nafion SAC-13. Results proved the advantages of flow reactor to achieve quite high glycerol conversion values in very short residence times, due to efficient contact of reactants with the solid catalyst, which was caused by higher catalyst to reactant ratio within the reactor. Results of batch reactor experiments obtained in the temperature range of 80–200 °C proved the importance of operating temperature on the catalytic performance of these materials. Amberlyst-15, which has the highest Brønsted acidity, gave the highest glycerol conversion at 90–100 °C. However, this material is unstable at temperatures higher than 110 °C. Performances of Amberlyst-36 and Relite EXC8D were the best in the range of 110–150 °C, which started to become unstable at 150 °C. Although the catalytic performance of Nafion-SAC-13 was not as good as Amberlyst type resins at temperatures up to 150 °C, its thermal stability was higher and could be used up to 200 °C. Although Brønsted acidity was the most important property of these materials in the etherification reaction of glycerol, results also proved the importance of diffusion resistance on the observed conversion values, which limited the penetration of glycerol to the active acid sites, especially in the catalysts with smaller pore diameters and at lower temperatures. Increased significance of swelling at higher temperatures, especially with Amberlyst-36 which had lower cross-linking in its structure and less rigidity, contributed to the penetration of the reactants to the active sites. Water produced during the etherification reaction was also shown to cause deactivation of the catalysts by reversible adsorption on the acid sites.
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esterification of free fatty acids in waste cooking oils wco role of ion exchange resins
Fuel, 2008Co-Authors: Nalan Ozbay, Nuray Oktar, Alper N TapanAbstract:Abstract Although WCO plays a crucial role for the economical production of biodiesel, free fatty acid (FFA) level in the nature of WCO cause saponification problems during transesterification. Acidic ion-exchange resins can be used to decrease WCO free fatty acid level. In this study, activities of resins (Amberlyst-15 (A-15), Amberlyst-35 (A-35), Amberlyst-16 (A-16) and Dowex HCR-W2) in direct FFA esterification were examined in the temperature range of 50–60 °C and the effect of catalyst amount (1–2 wt%) on FFA conversion was also analyzed. FFA conversion increased with increasing reaction temperature and catalyst amount. Order of catalytic activities was found as A-15 > A-35 > A-16 > Dowex HCR-W2. This was related to the size of average pore diameters and magnitude of BET surface area.
Zengqiang Zhang - One of the best experts on this subject based on the ideXlab platform.
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preparation of a carbon based solid acid catalyst by sulfonating activated carbon in a chemical reduction process
Molecules, 2010Co-Authors: Miao Huang, Zengqiang ZhangAbstract:Sulfonated (SO3H-bearing) activated carbon (AC-SO3H) was synthesized by an aryl diazonium salt reduction process. The obtained material had a SO3H density of 0.64 mmol·g-1 and a specific surface area of 602 m2·g-1. The catalytic properties of AC-SO3H were compared with that of two commercial solid acid catalysts, Nafion NR50 and Amberlyst-15. In a 10-h esterification reaction of acetic acid with ethanol, the acid conversion with AC-SO3H (78%) was lower than that of Amberlyst-15 (86%), which could be attributed to the fact that the SO3H density of the sulfonated carbon was lower than that of Amberlyst-15 (4.60 mmol·g-1). However, AC-SO3H exhibited comparable and even much higher catalytic activities than the commercial catalysts in the esterification of aliphatic acids with longer carbon chains such as hexanoic acid and decanoic acid, which may be due to the large specific surface area and mesoporous structures of the activated carbon. The disadvantage of AC-SO3H is the leaching of SO3H group during the reactions.
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preparation of a carbon based solid acid catalyst by sulfonating activated carbon in a chemical reduction process
Molecules, 2010Co-Authors: Xiaoyan Liu, Yulei Zhu, Miao Huang, Zengqiang Zhang, Jinming Gao, Xiaojin Han, Xiangyun GuoAbstract:Abstract: Sulfonated (SO 3 H-bearing) activated carbon (AC-SO 3 H) was synthesized by an aryl diazonium salt reduction process. The obtained material had a SO 3 H density of 0.64 mmol·g -1 and a specific surface area of 602 m 2 ·g -1 . The catalytic properties of AC-SO 3 H were compared with that of two commercial solid acid catalysts, Nafion NR50 and Amberlyst-15. In a 10-h esterification reaction of acetic acid with ethanol, the acid conversion with AC-SO 3 H (78%) was lower than that of Amberlyst-15 (86%), which could be attributed to the fact that the SO 3 H density of the sulfonated carbon was lower than that of Amberlyst-15 (4.60 mmol·g -1 ). However, AC-SO 3 H exhibited comparable and even much higher catalytic activities than the commercial catalysts in the esterification of aliphatic acids with longer carbon chains such as hexanoic acid and decanoic acid, which may be due to the large specific surface area and mesoporous structures of the activated carbon. The disadvantage of AC-SO
Alper N Tapan - One of the best experts on this subject based on the ideXlab platform.
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esterification of free fatty acids in waste cooking oils wco role of ion exchange resins
Fuel, 2008Co-Authors: Nalan Ozbay, Nuray Oktar, Alper N TapanAbstract:Abstract Although WCO plays a crucial role for the economical production of biodiesel, free fatty acid (FFA) level in the nature of WCO cause saponification problems during transesterification. Acidic ion-exchange resins can be used to decrease WCO free fatty acid level. In this study, activities of resins (Amberlyst-15 (A-15), Amberlyst-35 (A-35), Amberlyst-16 (A-16) and Dowex HCR-W2) in direct FFA esterification were examined in the temperature range of 50–60 °C and the effect of catalyst amount (1–2 wt%) on FFA conversion was also analyzed. FFA conversion increased with increasing reaction temperature and catalyst amount. Order of catalytic activities was found as A-15 > A-35 > A-16 > Dowex HCR-W2. This was related to the size of average pore diameters and magnitude of BET surface area.