Alcoholysis of Furfuryl Alcohol to Ethyl Levulinate Catalyzed by a Deep Eutectic Solvent

Abstract

In this study, the alcoholysis of furfuryl alcohol (FA) into ethyl levulinate (EL) using a deep eutectic solvent (DES) composed of choline chloride (ChCl) and ethanol was investigated by experiments and calculations. Experimental results reveal that the addition of 5-sulfonic acid salicylic acid (5-SSA) can catalyze the alcoholysis of FA to produce EL. The combined presence of ChCl and 5-SSA significantly improved the selectivity for EL. The mechanism of the alcoholysis of FA to EL in acidic DES was investigated by density functional theory (DFT) calculations in Gaussian 03. It was found that hydrogen-bond acceptor ChCl is coupled with hydrogen-bond donor ethanol to form a structure similar to HCl and ethoxy, which facilitates the alcoholysis of FA into EL.