Faculty Publications
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Item Synthesis of highly-branched alkanes for renewable gasoline(Elsevier B.V., 2020) Mascal, M.; Dutta, S.The gasoline market in the US is nearly twice that of diesel and jet fuel combined, and yet, nearly all research efforts to produce synthetic, biobased fuels center around these latter products. The reason for this is that a major component of gasoline is highly branched alkanes which, unlike straight chained products, are not readily derived from either fatty acid- or carbohydrate-based feedstocks. This review unpacks the motivations behind renewable gasoline synthesis and examines representative approaches to the targeted, de novo synthesis of densely-branched, high-octane isoalkanes and cycloalkanes employing chemocatalytic methods, as contrasted with the catalytic refining of biomass-derived feeds using petrochemical technologies. © 2019 Elsevier B.V.Item Recent advances in the preparation of levulinic esters from biomass-derived furanic and levulinic chemical platforms using heteropoly acid (HPA) catalysts(Elsevier B.V., 2021) Bhat, N.S.; Mal, S.S.; Dutta, S.The esters of biomass-derived levulinic acid (LA) have several potential applications, including cleaner-burning fuel additive, green solvent, fragrance ingredient, and a renewable chemical intermediate for downstream value addition. The levulinic esters (LEs) can be prepared by the acid-catalyzed alcoholysis of the biomass-derived furanic and levulinic chemical platforms such as LA, furfuryl alcohol (FAL), 5-(hydroxymethyl)furfural (HMF), and angelica lactone (AGL). The acid-catalyzed deconstruction of carbohydrates in an alcoholic medium affords the one-pot preparation of LEs. Choosing the right catalyst is of paramount importance for synthesizing LEs from both the economic and environmental perspectives. In this regard, heteropoly acids (HPAs), a class of polyoxometalates (POMs) bearing protons as the counter cation, have found widespread applications as acid catalysts in various organic transformations. HPAs are blessed with conducive properties such as controlled Brønsted and Lewis acidity, high thermal stability, robust structural features, non-toxic nature, tunable solubility, and less corrosiveness. Over the past several years, HPAs have found extensive applications as efficient and environment-friendly catalysts in biorefinery operations, including the synthesis of LEs. At this juncture, it is imperative to ascertain the achievements in this field to date and re-evaluate the challenges. This review attempts to provide up-to-date information about the preparation of LEs using HPA-based catalysts, critically analyze the literature cited, draw conclusions, and propose future prospects. © 2021 Elsevier B.V.Item Catalytic synthesis of renewable p-xylene from biomass-derived 2,5-dimethylfuran: a mini review(Springer Science and Business Media Deutschland GmbH, 2023) Dutta, S.; Bhat, N.S.In this work, the renewable synthesis of p-xylene (PX) from biomass-derived carbohydrates has been reviewed. PX is a crucial chemical feedstock and an essential starting material of polyethylene terephthalate (PET). PX can be produced selectively by the Diels-Alder reaction between ethylene and 2,5-dimethylfuran (DMF) followed by catalytic dehydration of the oxanorbornene adduct. DMF is primarily produced by the catalytic hydrogenation of 5-(hydroxymethyl)furfural (HMF), a furanic intermediate produced by the acid-catalyzed hydrolysis/dehydration of biomass-derived hexoses. With ethylene being sourced by dehydrating bioethanol, PET can be made biorenewable in its entirety. The atom economy and carbon efficiency of converting glucose into PX have been calculated. The existing literature (both theoretical and experimental) on the catalytic production of PX from DMF and ethylene are summarized, and future directions on this research have been proposed. The effect of Brønsted and Lewis acidity, porosity, and surface area of the heterogeneous catalysts on the selectivity and yield of PX have been highlighted. In addition, the techno-economic analysis of renewable PET, its future prospects based on the petroleum market, and the possibility of a circular economy of PET using chemical and enzymatic recycling strategies have been discussed. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Item 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 Valorization of biomass-derived furfurals: reactivity patterns, synthetic strategies, and applications(Springer Science and Business Media Deutschland GmbH, 2023) Dutta, S.The expertise of synthetic organic chemistry accumulated over the past century has been instrumental in converting biomass to fuels, chemicals, and materials. Particular emphasis has been attributed to using eco-friendly reagents and reaction conditions by adhering to the principles of green chemistry. Catalysis remains at the heart of organic synthesis and has a ubiquitous presence in the organic chemistry literature. Not surprisingly, catalytic processes are increasingly used in the chemistry of renewables under commercially relevant and environmentally acceptable conditions. In this review, the synthesis of various biofuels and renewable chemicals from biomass-derived furfural and 5-(hydroxymethyl)furfural has been elaborated. Synthetic upgrading of furfurals has been shown in the light of chemical modifications of the reactive sites present in them. This review aims to provide a critical understanding of the influence of synthetic organic chemistry in biomass value addition via the furanic platform. This work will encourage the researchers to improve the existing synthetic pathways, develop new synthetic strategies, and broaden the scope of applications for biorenewable products. Graphical abstract: [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.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 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 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 Ltd