Faculty Publications
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Item The hydrogen peroxide-mediated oxidation of biorenewable furfural to 2(5H)-furanone using heteropolyacids supported on ammonium y zeolite as the catalyst(Elsevier Ltd, 2020) Tiwari, R.; Bhat, N.S.; Mal, S.S.; Dutta, S.A series of heteropolyacid supported on ammonium Y zeolite (HPA-NH4YZ) catalysts were prepared and used for the catalytic oxidation of furfural to 2(5H)-furanone in aqueous hydrogen peroxide. The catalysts were characterized by PXRD, FTIR, TGA, and SEM analyses. The organic-solvent-free reaction was optimized on temperature, duration, loading of catalyst, and the equivalent of H2O2. The 20%PTA-NH4YZ catalyst showed the best catalytic activity giving 2(5H)-furanone in 40% isolated yield by solvent extraction under optimized conditions (20wt% cat., 100°C, 90min, 7.5eq. 30%H2O2). In addition, around 20% of succinic acid was recovered from the aqueous layer. © 2020 Elsevier Ltd. All rights reserved.Item A straightforward preparation of levulinic esters from biorenewable levulinic acid using methanesulfonic acid supported on silica gel (MSA-SG) as an efficient heterogeneous catalyst(Elsevier Ltd, 2023) Vinod, N.; Bandibairanahalli Onkarappa, S.; Madhwaraj Girija, V.; Dutta, S.The present work reports methanesulfonic acid supported on silica gel (MSA-SG) as an inexpensive heterogeneous solid acid catalyst for the high-yielding production of various alkyl levulinates from biomass-derived levulinic acid. The catalyst was characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). The reactions were conducted in a batch-type glass pressure reactor under conventional heating. The esterification reaction was optimized on temperature, duration, and catalyst loading. The optimized reaction conditions (120 °C, 8 h, 8 wt% MSA-SG) afforded methyl- to butyl levulinate in excellent isolated yields (≥90 %). The catalyst was filtered, and the products were purified by simply evaporating the excess alcohol reagent. © 2022Item Recent advances in the production and value addition of selected hydrophobic analogs of biomass-derived 5-(hydroxymethyl)furfural(Springer Science and Business Media Deutschland GmbH, 2023) Anchan, H.N.; Dutta, S.5-(Hydroxymethyl)furfural (HMF), produced by the acid-catalyzed dehydration of biomass-derived hexoses, is a well-recognized renewable chemical intermediate in the biorefinery research for the productions of fuels, chemicals, and materials. However, the inherent hydrophilicity and poor stability of HMF continue to disfavor its production and value addition from an economic standpoint. In this regard, the superior thermal and hydrolytic stability of the hydrophobic analogs of HMF simplify their isolation and purification from the aqueous (or polar) reaction media while enhancing their shelf life. The analogs show promises in supplanting HMF from its derivative chemistry. The halogenated derivatives of HMF, such as 5-(chloromethyl)furfural (CMF) and 5-(bromomethyl)furfural (BMF), can be produced directly from biomass in good isolated yields. The non-halogenated, hydrophobic derivatives of HMF include esters such as 5-(formyloxymethyl)furfural (FMF) and 5-(acetoxymethyl)furfural (AMF), obtained by the dehydration of carbohydrates in suitable carboxylic acids. The ethers of HMF, such as 5-(ethoxymethyl)furfural (EMF), can be produced directly by the acid-catalyzed alcoholysis of biomass. In addition, partially oxidized or reduced derivatives of HMF, such as 2,5-diformylfuran (DFF) and 5-methylfurfural (5MF), have also found significant interests as hydrophobic analogs of HMF. The production and value addition of various lipophilic analogs of HMF are rather scattered in the literature, and no comprehensive review is available in this area to date. This technical review attempts to fill that gap with up-to-date information with a critical analysis of the achievements and challenges. In this review, the production and derivative chemistry of various hydrophobic analogs of HMF have been discussed. The relative advantages and challenges associated with the preparation and value addition of various hydrophobic analogs of HMF are highlighted. Graphical abstract: [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.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 A scalable and high-yielding synthesis of 2-(2-furyl)-1,3-dioxolane from biomass derived furfural and ethylene glycol using heteropoly acids as green catalyst(Chemical Publishing Co., 2019) Tiwari, R.; Mal, S.S.; Dutta, S.In present work, Keggin-type commercial heteropoly acids have been employed as efficient solid acid catalysts in the acetalization of biomass-derived furfural with ethylene glycol. The reaction was optimized on parameters such as the type and loading of catalyst, duration of reaction and the relative ratio of reagents. The reaction was scaled up and the cyclic acetal 2-(furan-2-yl)-1,3-dioxolane was isolated in 92 % yield within 4 h using only 2 wt % of phosphotungstic acid in refluxing benzene. © 2019 Chemical Publishing Co.. All rights reserved.Item Efficient Synthesis of 5‑(Hydroxymethyl)furfural Esters from Polymeric Carbohydrates Using 5‑(Chloromethyl)furfural as a Reactive Intermediate(American Chemical Society, 2022) Bhat, N.S.; Hegde, S.L.; Dutta, S.; Sudarsanam, P.This work reports an efficient, gram-scale synthesis of 5-(hydroxymethyl)furfural (HMF) esters using biomass-derived 5-(chloromethyl)furfural (CMF) as a reactive intermediate. The HMF-esters have potential applications as chemical intermediates, fuel additives, and bioactive compounds. Initially, CMF was prepared in good yields directly from polymeric carbohydrates (starch, inulin, and cellulose) and cellulosic materials (cotton and filter paper) using a biphasic batch reaction system, consisting of aqueous hydrochloric acid and 1,2-dichloroethane. The use of ZnCl2 as an additive allowed the reaction to proceed under milder conditions while significantly improving the isolated yield of CMF. The effects of reaction temperature, reaction time, extracting solvent, and ZnCl2 loading on CMF yield were investigated. Microcrystalline cellulose was converted into CMF with a 72% isolated yield under optimized reaction conditions (80 °C, 2 h). After that, CMF was transformed into various novel esters of HMF in excellent isolated yields (>85%) by reacting with a slight excess amount of the triethylammonium salt of various alkyl/aryl carboxylic acids under solvent-free conditions. © 2022 American Chemical Society.Item [Et3NH][HSO4] as an efficient and inexpensive ionic liquid catalyst for the scalable preparation of biorenewable chemicals(Springer Science and Business Media Deutschland GmbH, 2022) Bhat, N.S.; Mal, S.S.; Dutta, S.Triethylammonium hydrogen sulfate (TEAHS) has been employed as an inexpensive protic ionic liquid catalyst for the preparation of various biomass-derived renewable compounds. TEAHS efficiently catalyzed the esterification of biomass-derived chemical intermediates such as levulinic acid, 2-furoic acid, stearic acid, and isosorbide. The scalable, cosolvent-free preparations were conducted in a batch-type glass pressure reactor, which provided excellent yields (> 80%) of the esters under moderate conditions. The TEAHS catalyst was conveniently separated from the reaction mixture and reused without significant loss of activity. Graphical abstract: [Figure not available: see fulltext.] © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
