Faculty Publications
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Item Nanocatalysis for renewable aromatics(wiley, 2022) Dutta, S.; Bhat, N.S.; Anchan, H.N.Chemocatalytic transformation of biomass feedstock, especially the non-food, inexpensive, and abundant terrestrial lignocellulose into fuels and chemicals, has multifaceted benefits, including the development of a sustainable economy and a cleaner environment. Aromatic compounds have a ubiquitous presence in the chemical industry. They must be accessed from biomass to supplant the same from fossilized resources. Several pathways have been developed to convert the major biomass components into aromatic hydrocarbons and functionalized aromatic compounds by catalytic methods. In this regard, heterogeneous nanocatalysts (NCs) have received particular attention since they have many superior properties, such as better selectivity, faster kinetics, and the requirement of lower loading due to higher activity, compared to the traditional heterogeneous catalysts of the micrometer scale. Polymeric carbohydrates like cellulose can be converted into furanic compounds first, which were then converted to benzene derivatives. The lignin fraction can be deconstructed into phenolics or further reduced into mononuclear aromatic hydrocarbons. Direct conversion of biomass into bio-oil containing aromatics is an alternative option. This chapter attempts to divulge the major pathways available to convert various biomass components into aromatic compounds emphasizing on the use of NCs for the chemical transformations. The accomplishments made to date and the challenges ahead are also emphasized. © 2023 John Wiley & Sons Ltd.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 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 Renewable synthesis of novel acrylates from biomass-derived 5-substituted-2-furaldehydes by Morita-Baylis-Hillman reaction(John Wiley and Sons Inc, 2023) Anchan, H.N.; Dutta, S.Biomass-derived furfurals are becoming increasingly popular as renewable chemical building blocks for synthesizing specialty chemicals. Morita-Baylis-Hillman (MBH) reaction is a classic carbon-carbon bond-forming transformation between the α-position of an activated alkene and a carbon electrophile (e. g., aldehyde) using a nucleophilic catalyst, such as a tertiary amine or phosphine. The MBH reaction is highly atom economical, affords excellent yields of adducts under mild reaction conditions, introduces substantial molecular complexity, and enjoys broad substrate scope. In this work, several novel MBH adducts have been synthesized starting from biomass-derived 5-substituted-2-furaldehydes and acrylates using 1,4-diazabicyclo[2.2.2]octane (DABCO) as the organocatalyst. This work reports the first systematic study of the MBH reaction of 5-substituted-2-furaldehydes and acrylates. A general synthetic protocol for the high-yielding synthesis of MBH adducts has been developed. The reactions were performed at room temperature under solvent-free conditions, and the spectroscopically pure products were produced in good to excellent isolated yields. Moreover, DABCO was recovered from the reaction mixture and successfully recycled. © 2023 Wiley-VCH GmbH.Item Efficient Synthesis of Novel Biginelli and Hantzsch Products Sourced from Biorenewable Furfurals Using Gluconic Acid Aqueous Solution as the Green Organocatalyst(American Chemical Society, 2023) Anchan, H.N.; Naik C, P.; Bhat, N.S.; Kumari, M.; Dutta, S.The Biginelli reaction provides 3,4-dihydropyrimidin-2(1H)-ones (DHPMs), whereas the Hantzsch reaction leads to 1,4-dihydropyridines (DHPs) by the one-pot, multicomponent, and operationally simple transformations starting from readily available starting materials. DHPMs and DHPs are well-established heterocyclic moieties in the synthetic organic chemistry literature and have pronounced pharmacological activities. This work reports the synthesis of novel DHPMs and DHPs from carbohydrate-derived 5-substituted-2-furaldehydes by employing gluconic acid aqueous solution (GAAS) as an efficient, inexpensive, and eco-friendly catalyst. The use of urea (or thiourea) as the reagent led to DHPMs, whereas ammonium acetate produced DHPs, selectively, keeping the other two starting materials (i.e., furfurals and ethyl acetoacetate) and the reaction parameters unaltered. Using the general synthetic protocol under optimized reaction conditions (60 °C, 3-6 h, 25 mol % GAAS cat.), all the DHPM and DHP derivatives were obtained in good to excellent isolated yields. © 2023 The Authors. Published by American Chemical SocietyItem Activated Carbon from Cashew Nut Husk and Cashew Nut Shell Wastes: Synthesis, Characterization, and Adsorption Studies(John Wiley and Sons Inc, 2023) Anchan, H.N.; Jadhav, S.; Dutta, S.Activated carbon (AC) is a key material in numerous industrial applications, including wastewater treatment, catalysis, personal care products, and pharmaceutical industry. Producing AC from waste biomass is of much interest since the environmental footprint is low and the economics are favorable for most applications. Cashew nut husk (CNH) and cashew nut shell (CNS) are typically considered wastes in the cashew nut processing industry. Synthesis of AC from CNH and CNS allows value addition of these materials and improves the economic prospects of the cashew nut processing industry. Herein, we report the production of AC by carbonization of CNH and CNS using orthophosphoric acid as the activating agent. The results showed that 700 °C is a suitable activation temperature for CNH, whereas 500 °C was enough for activating CNS. The AC samples were extensively characterized by FTIR, PXRD, BET, and FESEM-EDX analysis. The AC produced from CNH at 700 °C (H-700) exhibited a very high specific surface area and iodine number of 1511 m2/g and 961 mg/g, respectively. Therefore, H-700 was used for adsorbing methylene blue from water as a model for wastewater treatment. The H-700 sample showed an adsorption capacity of 520 mg/g with good recyclability up to five cycles. © 2023 Wiley-VCH GmbH.