Faculty Publications
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Item Catalytic conversion of glucose and its biopolymers into renewable compounds by inducing C–C bond scission and formation(Springer Science and Business Media Deutschland GmbH, 2024) Anchan, H.N.; Bhat, N.S.; Vinod, N.; Prabhakar, P.S.; Dutta, S.Transportation fuels and chemicals can be produced renewably by selectively altering the carbon skeleton of biomass-derived glucose. The predominantly catalytic processes incorporate carbon–carbon (C–C) bond scission and formation reactions with concomitant defunctionalization and refunctionalization steps. The production and synthetic upgrading of various biochemicals achieved by the C–C bond-scission (C1–C5) and C–C bond-forming (> C6) reactions from glucose and its biopolymers (e.g., starch, cellulose) have been reviewed. The details of transforming glucose and its polymers into targeted biochemicals, such as mechanistic pathway, process parameters, product selectivity, and specifics of the catalysts employed, have been elaborated. The interconversions of these chemicals of commercial significance under catalytic conditions are also highlighted. This review will assist the researchers in comprehending this field from a distinct perspective, reassess the challenges, identify the research gaps, and critically appraise the emerging research avenues. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022.Item Synthesis and Characterization of Novel Pd@rGO−CuFe2O4 Magnetic Nanoparticles: A Recyclable Catalyst for C−C Coupling Reaction in Biomass-Derived Organic Solvent(John Wiley and Sons Inc, 2023) Teli, Y.A.; Reetu, R.; Singh, P.G.; Patel, M.J.; Dash, S.; Paine, S.; Prabhakar, P.S.; Singh, V.; Keremane, K.S.; Al-Zaqri, N.; Mukherjee, K.; Dutta, S.; Malakar, C.C.Development of new, cost effective, stable heterogeneous catalyst for the organic transformations is an important thematic area of research. Present work describes the development of new Pd@rGO−CuFe2O4 catalyst and demonstrates its effectiveness for Suzuki-Miyaura type coupling reactions. The additional advantage of this reaction is its feasibility using biomass-derived solvent like γ-Valerolactone (GVL) in aqueous media. The catalyst is prepared hydrothermally and characterized using XRD, FESEM, EDX, and XPS analysis. The catalyst exhibits excellent activity and recyclability (up to six times) in the C−C coupling reaction to deliver the corresponding biaryl molecules in yields up to 90 %. High efficiency for the conversion of nitriles to amides is also revealed by the prepared catalyst. © 2023 Wiley-VCH GmbH.Item Aqueous solution of biogenic carboxylic acids as sustainable catalysts and green reaction media for the high-yielding synthesis of Biginelli adducts, Hantzsch esters, and substituted pyridines(Royal Society of Chemistry, 2024) Prabhakar, P.S.; Sahoo, J.; Alnaser, I.A.; Seikh, A.H.; Karim, M.R.; Dutta, S.3,4-Dihydropyrimidin-2(1H)-ones (DHPMs) and 1,4-dihydropyridines (DHPs), prepared by applying the Biginelli and Hantzsch reaction protocols, respectively, are well-documented nitrogen-containing heterocycles with intriguing pharmacological properties. The aqueous solution of biogenic carboxylic acids renewably produced from biomass via catalytic or enzymatic processes can be used as a sustainable catalyst and green reaction media for synthesizing DHPs and DHPMs. This work evaluates the efficacy of various biogenic acids in their aqueous solutions as catalysts for synthesizing DHPs and DHPMs from substituted benzaldehydes. Among the studied biogenic acids, gluconic acid aqueous solution (GAAS) proved to be the most efficient, safe, non-volatile, and recyclable catalyst. The reaction afforded excellent isolated yields (≥85%) of spectroscopically pure DHPs and DHPMs under optimized conditions and employed a straightforward work-up procedure. Aqueous ammonia was successfully employed instead of ammonium salt to improve the atom economy of DHPs. Moreover, substituted pyridines were synthesized from DHPs in a one-pot, two-step process using NaNO2 as an oxidant in the GAAS medium. This journal is © The Royal Society of Chemistry, 2024Item Extending the Carbon Chain Length of Carbohydrate-Derived 5-Substituted-2-furaldehydes by Condensing with Active Methylene Compounds under Organocatalytic Conditions(American Chemical Society, 2024) Prabhakar, P.S.; Seikh, A.H.; Karim, M.R.; Dutta, S.This work reports a high-yielding, organic solvent-free, gram-scale synthesis of novel Knoevenagel condensation products by reacting carbohydrate-derived 5-substituted-2-furaldehydes (SFLs) with active methylene compounds (AMCs) using various organic amines and inorganic bases as catalysts. Among the base catalysts examined, piperidine performed best, affording satisfactory selectivity and yield of the targeted Knoevenagel condensation products owing to the subtle balance between its nucleophilicity and basicity. The reaction was optimized on various reaction parameters, such as temperature, duration, solvent, catalyst loading, and molar ratio of the reactants. Even though the SFLs exhibited significantly different reactivity, a general synthetic protocol was developed successfully, affording good to excellent isolated yields (70-96%) of the novel Knoevenagel condensation products at ambient temperature. Moreover, the Knoevenagel products were purified by triturating with eco-friendly solvents (e.g., ethyl acetate and n-heptane) without chromatographic purification. © 2024 The Authors. Published by American Chemical Society.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 Ketalization of carbohydrate-derived levulinic esters using cellulose sulfuric acid as a heterogeneous catalyst: a closed-loop biorefinery approach(Royal Society of Chemistry, 2025) Prabhakar, P.S.; Dutta, S.Levulinic ester ketals (LEKs) are carbohydrate-derived renewable chemicals with potential applications as chemical building blocks, fuel additives, solvents, monomers, and plasticizers. This work reports the synthesis of ethyl levulinate ethylene glycol ketal (LEK 1) and ethyl levulinate propylene glycol ketal (LEK 2) by the ketalization of carbohydrate-derived ethyl levulinate using cellulose sulfuric acid (CSA) as an efficient and recyclable heterogeneous acid catalyst. Cyclohexane was used as the solvent to remove water formed in the reaction by azeotropic distillation, and nearly quantitative isolated yields of LEK 1 and LEK 2 were obtained under optimized parameters. The transformation was optimized on various process parameters, and the CSA catalyst was successfully recycled. Using CSA as a catalyst for producing LEKs shows promise for a closed-loop carbohydrate-centric biorefinery approach. © 2025 The Royal Society of Chemistry.