Studies on green synthesis of glycerol carbonate from waste cooking oil derived glycerol over an economically viable NiMgOx heterogeneous solid base catalyst

Abstract

The present study includes the transesterification reaction of waste glycerol produced in biodiesel industries with dimethyl carbonate (DMC) in presence of magnesium nickel-based mixed oxide, an economically and highly potent cost-effective heterogeneous base catalyst. The catalyst was synthesized in different molar ratios via co-precipitation route. The main objective of this work is value addition of bio glycerol which is major drawbacks in biodiesel industries and economization of biodiesel production process through one of the value added product glycerol carbonate. First-time Ni Mg based mixed oxide catalyst was used in glycerol carbonate synthesis and obtained 82% yield at optimized reaction condition. The physicochemical characteristics of catalysts were analyzed through powder X-ray diffraction (XRD), SEM-EDX, N2-sorption, XPS, FTIR spectroscopy, TGA-DSC. The Gibbs free energy change (ΔG#) and enthalpy of activation (ΔH#) for transesterification reaction of glycerol was found to be 16.547 kJ mol-1 and118.73 kJmol-1 respectively. The positive value of Gibbs free energy change suggested the transesterification of glycerol followed endothermic non spontaneous pathway. Optimization of several reaction parameters like reaction time, temperature, DMC to GLY molar ratio, Catalyst loading percentage were well explained also the green chemistry metrices of the catalyst was studied and found to be very suitable for transesterification reaction of glycerol.