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 Hydrochloric acid-catalyzed coproduction of furfural and 5-(chloromethyl)furfural assisted by a phase transfer catalyst(Elsevier Ltd, 2020) Bhat, N.S.; Vinod, N.; Onkarappa, S.B.; Dutta, S.Furfural has been produced in 53% isolated yield from D-xylose within an aqueous HCl-1,2-dichloroethane biphasic reaction mixture using benzyltributylammonium chloride (BTBAC) as a phase transfer catalyst. The use of BTBAC noticeably improved the yield of furfural compared to that in the control reaction. The reaction was optimized on the reaction temperature, duration, concentration of HCl, and the loading of BTBAC. Furfural and 5-(chloromethyl)furfural (CMF) have also been coproduced from a mixture of pentose and hexose sugars. Under optimized conditions (100 °C, 3 h, 20.2% HCl, 10 wt% BTBAC), CMF and furfural were isolated in 17% and 53% yield, respectively, from a mixture of glucose and xylose. In addition, levulinic acid was isolated from the aqueous layer in 31% yield. © 2020 Elsevier LtdItem Production of 5-(formyloxymethyl)furfural from biomass-derived sugars using mixed acid catalysts and upgrading into value-added chemicals(Elsevier Ltd, 2020) Dutta, S.In this work, 5-(formyloxymethyl)furfural (FMF) has been produced from biomass-derived hexose sugars within a biphasic reaction mixture consisting of aqueous formic acid (85%), a strong Brønsted acid catalyst, and 1,2-dichloroethane as an organic extractant. Using a combination of aqueous hydrobromic acid and formic acid, under optimized condition (80 °C, 8 h, 10 wt% substrate loading), 68% isolated yield of FMF was obtained from fructose. FMF has been demonstrated as a renewable chemical building block for the synthesis of renewable chemicals of commercial significance such as 5-methylfurfural, 2,5-diformylfuran, and 2,5-furandicarboxylic acid in good to excellent isolated yields. © 2020 Elsevier LtdItem 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 [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 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 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 Upgrading of coconut shell-derived pyrolytic bio-oil by thermal and catalytic deoxygenation(Taylor and Francis Ltd., 2024) Dasari, K.K.; Gumtapure, V.; Dutta, S.The objective of this study is to upgrade the pyrolysis oil obtained from coconut shells via thermal deoxygenation and catalytic hydrodeoxygenation (HDO) and compare the elemental properties of the upgraded bio-oil samples. The crude coconut shell pyrolysis oil (cr-CSPO) was obtained in 33% yield by intermediate pyrolysis (575°C) of pre-dried coconut shells. The higher heating value (HHV) of cr-CSPO was found to be 16.46 MJ/Kg. The thermal and catalytic upgrading was done at 250°C, 30 bar of hydrogen pressure, a reaction time of 3 h, and a stirring speed of 350 rpm. In the case of catalytic upgrading, 10% Pd/C (10 wt% of cr-CSPO) was used as the catalyst. Thermally heating the cr-CSPO under identical conditions without the catalyst provided oil of HHV 25.94 MJ/kg. Catalytic HDO of the cr-PCSO showed a noticeable increase in the HHV value to 30.57 MJ/kg. The results indicate significant improvement in the combustion properties of cr-CSPO by thermal treatment and more so by the catalytic HDO chemistry. © 2020 Taylor & Francis Group, LLC.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.