Phosphotungstic acid supported on waste sugarcane bagasse: A sustainable and recyclable catalyst for the synthesis of biofuel additives from levulinic acid

Abstract

In order to satisfy the growing energy demand, the globe is centred on catalytic upgradation of bio platform molecules to synthesize biofuel, an energy chemical. In this regard, levulinate esters have gained more attention in view of its excellent potential as fuel-blending agent. The present article demonstrated the synthesis of butyl levulinate over a novel biomass derived catalyst (PTA/SB) based on Phosphotungstic acid (PTA) functionalized sugarcane bagasse (SB). The SB and PTA/SB were characterized by various physicochemical and spectral techniques such as acidity measurements, NH₃-TPD, N₂ adsorption-desorption, FTIR, UV–Vis–NIR, TGA-DTG, XRD and SEM analysis. The synthesized catalyst shows excellent conversion of 95 % with high Turnover number (1377) at relatively milder conditions. The activation energy for said reaction was calculated by performing kinetics experiments at different temperatures. As various alkyl esters are industrially important specifically for fuel blending, the substrate study was carried out with different acids and alcohols (straight chain C1–C7) to scrutinize viability of catalyst and the obtained results clearly revels that for every different substrate the catalyst shows more than 60 % conversion and 99 % selectivity of alkyl ester. The catalyst depicts successive recyclability up to three cycles.