Faculty Publications
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Item Selective oxidation of biomass-derived furfural to 2(5H)-furanone using trifluoroacetic acid as the catalyst and hydrogen peroxide as a green oxidant(Springer Science and Business Media Deutschland GmbH, 2023) Bhat, N.S.; Kumar, R.; Jana, A.; Mal, S.S.; Dutta, S.In this work, biomass-derived furfural has been selectively oxidized to 2(5H)-furanone using aqueous hydrogen peroxide as the green oxidant. Among various homogeneous acid catalysts screened for the transformation, trifluoroacetic acid (TFA) was found to be the most suitable candidate that afforded up to 52% isolated yield of 2(5H)-furanone under mild conditions (RT, 1 h). In addition, succinic acid was recovered in nearly 20% yield from the aqueous layer. The organic solvent-free, gram-scale reaction was optimized on temperature, the molar ratio of H2O2 and furfural, and the amount of TFA used. [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.Item Efficient preparation of hybrid biofuels from biomass-derived 5-(acetoxymethyl)furfural and petroleum-derived aromatic hydrocarbons(Royal Society of Chemistry, 2024) Yadav, A.K.; Bhat, N.S.; Kaushik, S.; Seikh, A.H.; Dutta, S.Fuel candidates containing both petroleum-derived and biomass-derived molecules in their structural motifs ensure both feedstocks are used optimally and coherently. This work reports a straightforward and efficient preparation of 5-(arylmethyl)furfurals (AMFFs), 2-(arylmethyl)furans (AMFs), and 2-(arylmethyl)-5-methylfurans (AMMFs) as hybrid biofuels (or fuel oxygenates) starting from carbohydrate-derived 5-(acetoxymethyl)furfural (AcMF) and petroleum-derived aromatic hydrocarbons. The AMFFs were prepared by Friedel-Crafts reaction between AcMF and aromatic hydrocarbons (e.g., BTX, mesitylene) by employing anhydrous ZnCl2 as the catalyst. AMFs were prepared by decarbonylation of AMFFs over the Pd(OAc)2 catalyst under solvent-free conditions. In contrast, AMMFs were produced by hydrogenating AMFFs in methanol using gaseous hydrogen and the 10% Pd/C catalyst. The catalytic transformations were optimized on various parameters, and all the biofuel candidates were obtained in good to excellent isolated yields (>80%) under moderate conditions. © 2024 The Royal Society of Chemistry.Item Synthesis, characterization, and antibacterial activity of novel bis(indolyl)methanes sourced from biorenewable furfurals using gluconic acid aqueous solution (GAAS) as a sustainable catalyst(Royal Society of Chemistry, 2024) Naik C, P.; Ashoka, G.B.; Seikh, A.H.; Dutta, S.Bis(indolyl)methanes (BIMs) are important heterocycle-containing molecular scaffolds that show remarkable biological and pharmacological activities. This work reports the synthesis of novel BIMs using carbohydrate-derived 5-substituted-2-furaldehydes as renewable reactants. Structural diversity was introduced in the BIMs as substituents in the indole and furaldehyde moieties. Various commonly encountered biorenewable carboxylic acids were screened as catalysts for the acid-catalyzed transformation under organic solvent-free conditions. All the novel BIMs were characterized by spectroscopic techniques (FTIR, 1H-NMR, 13C-NMR) and elemental analysis. The reaction was optimized on the reaction temperature, duration, catalyst type, and catalyst loading. The gluconic acid aqueous solution (GAAS) showed the best catalytic activity for the transformation, affording satisfactory isolated yields (68-96%) of the targeted BIMs under optimized conditions. The GAAS catalyst was conveniently recovered from the reaction mixture and reused for four consecutive cycles without catastrophic loss in either mass or activity. Moreover, the antibacterial activities of the novel BIMs were studied on Gram-positive and Gram-negative bacterial strains, such as Enterococcus faecalis and Pseudomonas syringae. © 2024 The Royal Society of Chemistry.Item Sustainable synthesis of novel 3-(2-furyl)acrylic acids and their derivatives from carbohydrate-derived furfurals by chemical catalysis(Springer Science and Business Media Deutschland GmbH, 2024) Prabhakar, P.S.; Dutta, S.This work reports the renewable synthesis of 3-(2-furyl)acrylic acid and its novel-substituted derivatives, with potential applications as sustainable chemical building units, starting from carbohydrate-derived 5-substituted-2-furaldehydes and malonic acid employing various organocatalysts. Piperidinium acetate as the catalyst afforded good to excellent isolated yields of the acrylic acids under solvent-free conditions. The substituted 3-(2-furyl)acrylic acids were esterified using MeSO3H/SiO2 as a heterogeneous acid catalyst. The 3-(2-furyl)acrylic acids containing acid-sensitive functional groups on the furan ring were esterified by dimethyl carbonate as the sustainable reagent by base-catalyzed transesterification reaction. Moreover, the olefinic group was selectively reduced by catalytic hydrogenation using 5%Pd/C as the catalyst. The catalytic processes were optimized on various reaction parameters, and the synthesized compounds were characterized by FTIR, NMR (1H, 13C), and elemental analysis. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2023.Item Mechanochemical synthesis of Knoevenagel condensation products from biorenewable furaldehydes using crustacean waste-derived chitosan as a sustainable organocatalyst(Royal Society of Chemistry, 2025) Rachitha, S.N.; Yadav, A.K.; Kamali, M.; Sudarsanam, P.; Dutta, S.The biorefinery processes employing renewable feedstock can benefit from sustainable synthetic practices, such as mechanochemistry, organocatalysis, and renewable catalysts. This work reports using crustacean waste-derived chitosan (CS) as an eco-friendly and recyclable heterogeneous organocatalyst for the Knoevenagel condensation reaction between biorenewable 5-substituted-2-furaldehydes and malononitrile. The reaction was performed under solvent-free, mechanochemical conditions in a mortar and pestle. The reaction kinetics were faster, and the product selectivity was higher under mechanochemical conditions than in solvent-mediated synthesis. The CS catalyst was conveniently recovered and recycled. Moreover, the Knoevenagel condensation reaction was extended to substituted benzaldehydes to demonstrate the broad substrate scope of the process. In all cases, the Knoevenagel condensation products were isolated in excellent yields (>85%) in <30 min at RT. The CS (fresh and recycled) catalysts were characterized by UV-Vis, FTIR, PXRD, SEM-EDX, DSC, TGA, and elemental analysis techniques. © 2025 The Royal Society of Chemistry.