Faculty Publications
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Item Hydrogen-Economic Synthesis of Gasoline-like Hydrocarbons by Catalytic Hydrodecarboxylation of the Biomass-derived Angelica Lactone Dimer(Wiley Blackwell info@wiley.com, 2017) Chang, F.; Dutta, S.; Mascal, M.The biomass-derived platform molecule levulinic acid is converted into the angelica lactone dimer (ALD) in high overall yield using simple inorganic catalysts. Hydrodecarboxylation of ALD using a Pd/?-Al2O3 catalyst under moderate hydrogen gas pressure at high temperatures generates branched C8–C9 hydrocarbons in nearly quantitative yield consuming as little as a single equivalent of external hydrogen. These molecules are high-octane “drop-in” equivalents of isoalkanes used in commercial gasoline. Catalytic hydrodecarboxylation is presented as a highly effective means to reduce hydrogen demand in biomass-to-biofuel conversion technologies. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimItem Preparation of alkyl levulinates from biomass-derived 5-(halomethyl)furfural (X = Cl, Br), furfuryl alcohol, and angelica lactone using silica-supported perchloric acid as a heterogeneous acid catalyst(Springer Science and Business Media Deutschland GmbH, 2020) Onkarappa, S.B.; Bhat, N.S.; Dutta, S.This work reports the synthesis of a series of alkyl levulinates from biomass-derived 5-(halomethyl)furfural (X = Cl, Br), furfuryl alcohol, and angelica lactone using silica-supported perchloric acid (HClO4-SiO2) as a heterogeneous acid catalyst. The solvent-free, one-pot preparation afforded levulinate esters in excellent isolated yields (> 84%). The reactions were performed at 120 °C for 6 h in a batch-type glass pressure reactor using XMF and furfuryl alcohol in presence of excess of the alcohol reagent and 4 wt.% of the HClO4-SiO2 catalyst (0.028 mmol HClO4). Furthermore, the reaction protocol was extended for the synthesis of ALs starting with angelica lactone at 90 °C for 2 h in a round-bottomed flask by using excess alcohol and 4 wt.% of the HClO4-SiO2 catalyst. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.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.Item Efficient Preparation of the Esters of Biomass-Derived Isohexides by Base-Catalyzed Transesterification under Solvent-Free Conditions(American Chemical Society, 2023) Bhat, N.S.; Vinod, N.; Tarafder, K.; Nayak, M.K.; Jana, A.; Mal, S.S.; Dutta, S.The monoesters and diesters of glucose-derived isosorbide (IS) have potential applications as sustainable dispersants, surfactants, emulsifiers, monomer units for polymers, and plasticizers. This work reports a solvent-free, high-yielding, and scalable pathway for producing the monoesters and diesters of IS by a transesterification reaction using K2CO3 as an efficient, inexpensive, and recyclable base catalyst. In the case of monoesters, the selectivity toward the exo-monoester of IS was found higher than that toward the endo-monoester. The methodology was successfully extended to synthesize the monoesters and diesters of isomannide and isoidide. The gram-scale preparation of alkyl, vinyl, and aryl esters of isohexides was optimized on the reaction temperature, duration, equivalence of the ester reagent, and catalyst loading. Under optimized conditions (50 mol % K2CO3, 180 °C, 6 h), various aryl and alkyl esters of the isohexides were isolated in satisfactory yields. The unsymmetrical diesters of the isohexides were conveniently synthesized by stepwise transesterification. © 2023 American Chemical Society.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 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.