Faculty Publications
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Item Efficient and Scalable Production of Alkyl Levulinates from Cellulose-Derived Levulinic Acid Using Heteropolyacid Catalysts(Wiley-Blackwell info@wiley.com, 2019) Onkarappa, S.B.; Javoor, M.; Mal, S.S.; Dutta, S.This work reports a straightforward and scalable synthesis of a series of alkyl levulinates from cellulose-derived levulinic acid and alkyl alcohols using commercially available heteropolyacid catalysts under homegenous conditions. The reaction was optimized on parameters such as temperature, molar ratio of reagents, type and loading of catalyst. The solvent-free reactions afforded alkyl levulinates in high isolated yields (>85%) using only slight excess of alcohols and 10 wt% of catalyst at 120 °C in 6 h. Further, the catalysts were successfully recycled for three consecutive cycles without significant loss in activity. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimItem Phase Transfer Catalyst Assisted One-Pot Synthesis of 5-(Chloromethyl)furfural from Biomass-Derived Carbohydrates in a Biphasic Batch Reactor(Wiley-Blackwell info@wiley.com, 2019) Onkarappa, S.B.; Dutta, S.5-(Chloromethyl)furfural (CMF), a bio-renewable chemical building block, has been produced in good isolated yields from biomass-derived carbohydrates within a closed aqueous HCl-1,2-dichloroethane biphasic reactor in the presence of benzyltributylammonium chloride (BTBAC) as a phase transfer catalyst (PTC). The solvent-economic, one-pot strategy afforded CMF in 73% isolated yield (90 °C, 3 h) from sucrose with a combined yield of 84% for CMF and levulinic acid. The process was optimized on temperature, duration, solvent, type, and loading of PTC. Use of BTBAC led to nearly 10% increase in yield of CMF for all substrates when compared to control reactions. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimItem Hydrochloric acid-catalyzed coproduction of furfural and 5-(chloromethyl)furfural assisted by a phase transfer catalyst(Elsevier Ltd, 2020) Bhat, N.S.; Vinod, N.; Onkarappa, S.B.; Dutta, S.Furfural has been produced in 53% isolated yield from D-xylose within an aqueous HCl-1,2-dichloroethane biphasic reaction mixture using benzyltributylammonium chloride (BTBAC) as a phase transfer catalyst. The use of BTBAC noticeably improved the yield of furfural compared to that in the control reaction. The reaction was optimized on the reaction temperature, duration, concentration of HCl, and the loading of BTBAC. Furfural and 5-(chloromethyl)furfural (CMF) have also been coproduced from a mixture of pentose and hexose sugars. Under optimized conditions (100 °C, 3 h, 20.2% HCl, 10 wt% BTBAC), CMF and furfural were isolated in 17% and 53% yield, respectively, from a mixture of glucose and xylose. In addition, levulinic acid was isolated from the aqueous layer in 31% yield. © 2020 Elsevier Ltd