Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
Search Results
Item Ketalization of carbohydrate-derived levulinic esters using cellulose sulfuric acid as a heterogeneous catalyst: a closed-loop biorefinery approach(Royal Society of Chemistry, 2025) Prabhakar, P.S.; Dutta, S.Levulinic ester ketals (LEKs) are carbohydrate-derived renewable chemicals with potential applications as chemical building blocks, fuel additives, solvents, monomers, and plasticizers. This work reports the synthesis of ethyl levulinate ethylene glycol ketal (LEK 1) and ethyl levulinate propylene glycol ketal (LEK 2) by the ketalization of carbohydrate-derived ethyl levulinate using cellulose sulfuric acid (CSA) as an efficient and recyclable heterogeneous acid catalyst. Cyclohexane was used as the solvent to remove water formed in the reaction by azeotropic distillation, and nearly quantitative isolated yields of LEK 1 and LEK 2 were obtained under optimized parameters. The transformation was optimized on various process parameters, and the CSA catalyst was successfully recycled. Using CSA as a catalyst for producing LEKs shows promise for a closed-loop carbohydrate-centric biorefinery approach. © 2025 The Royal Society of Chemistry.Item One-pot production of 5-(chloromethyl)furfural and levulinic acid from marine carbohydrates(Springer Science and Business Media Deutschland GmbH, 2025) C, P.N.; Yadav, A.K.; Aranha, D.A.; Dutta, S.5-(Chloromethyl)furfural (CMF) and levulinic acid (LA) were produced from marine biomass-derived carrageenan (? and ?) and chitin. CMF was produced in HCl (aq., 35%)-1,2-dichloroethane biphasic reaction within a batch-type glass pressure reactor, whereas LA was produced in the same setup using aqueous HCl (20%) only. The reactions were optimized on temperature, duration, stirring speed, volume of solvent, and feedstock loading. The isolated yield of CMF reached 37.8% starting from ?-carrageenan (80 °C, 2 h), whereas chitin afforded a 21.8% yield of CMF (100 °C, 4 h). LA was obtained in a 52.3% yield from ?-carrageenan (120 °C, 4 h) and 36% from chitin (150 °C, 4 h). The mixture of CMF and LA was then converted into HMF-levulinate, a prospective fuel oxygenate, in a one-pot process, affording a 77.8% isolated yield. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.Item Comprehensive utilization of crustacean wastes by chemical-catalytic transformations using levulinic acid as a sustainable platform chemical(Springer Science and Business Media Deutschland GmbH, 2025) C, P.N.; Nowl, M.S.; Mandal, S.; Dutta, S.Shell residues from seafood processing and aquaculture industries encounter significant challenges in waste management. There are many traditional and emerging applications of shell waste, but their enormous scale of production outpaces the utilization. This work reports the comprehensive utilization of shell waste by sequentially converting their major components into value-added products by selective chemical transformations. The pigments were extracted using ?-valerolactone (GVL), a biorenewable solvent produced from carbohydrate-derived levulinic acid (LA). The protein component was separated from shells under hydrothermal conditions with or without using any inorganic base. The calcite component was then reacted with LA and formic acid to form calcium levulinate and calcium formate, promising dietary supplements and chemical feedstock. Finally, chitin was converted into LA (30 mol%) under optimized conditions (150 °C, 4 h). Separation and value-addition of the components of crustacean exoskeletons demonstrated in this work are scalable, the products are marketable, and the catalyst used is recyclable. LA produced from chitin is used as the reagent and for synthesizing GVL for a closed-loop biorefinery. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.