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 Efficient Preparation of Alkyl Benzoates by Heteropolyacid-Catalysed Esterification of Benzoic Acid under Solvent-Free Condition(Wiley-Blackwell, 2019) Tiwari, R.; Rahman, A.; Bhat, N.S.; Onkarappa, S.B.; Mal, S.S.; Dutta, S.This study reports a high-yielding, solvent-free, and scalable synthesis of alkyl benzoates from benzoic acid and its derivatives using heteropolyacids (HPA) as efficient and recyclable acid catalysts. The alkyl benzoates were obtained in excellent isolated yields (>85%) within 4 h at 120 °C using 1.5 equivalent of the alcohol reagent and only 0.4 mol% of the phosphotungstic acid (PTA) catalyst. The PTA catalyst was conveniently recovered and reused for three consecutive cycles without significant loss in mass or activity. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim