Electrosynthesis of Glycerol Carbonate from Glycerol and Potassium Carbonate on Nickel Electrodes

Abstract

The reaction of glycerol and carbonate ions to produce glycerol carbonate, a valuable chemical feedstock, would solve both a glycerol problem for biorefineries and carbon dioxide emissions. The electrosynthesis of glycerol carbonate has been performed under ambient temperature and pressure on nickel plate electrodes, using potassium carbonate dissolved in glycerol with varying water concentrations. Analysis by Liquid Chromatography-Mass Spectrometry (LC-MS) with analytical standards showed the reaction produced exclusively the more valuable 5-membered-ring glycerol-1,2-carbonate, instead of the 6-membered-ring glycerol-1,3-carbonate, likely due to steric hindrance. LC-MS analysis further revealed C=O bond hydrogenation and dimerization of glycerol carbonate. Cyclic Voltammetry (CV) suggests the reaction follows an Electrochemical-Chemical (EC) mechanism. The brown color evolved from the anode indicated oxidative formation of brown polyacrolein as by-product. Addition of water was found to be beneficial by reducing heating requirements and resistive loss. From the results, the electrochemical formation of glycerol carbonate was successfully demonstrated.