Insights into the metal salt catalyzed ethyl levulinate synthesis from biorenewable feedstocks

Abstract

Ethyl levulinate (EL) synthesis from biorenewable feedstocks in the presence of metal salts and under non-microwave instant heating reaction environment has been studied. Initial screening suggested CuCl2 and FeCl3 as an efficient catalyst for EL synthesis from 5-hydroxymethylfurfural (HMF), thereby resulting into 47.5% and 43.3% EL yield respectively at 160°C in 5min. Interestingly, environmentally benign and widely available metal salt, AlCl3, was found to yield comparable EL (39.0%) when experiments were performed under identical reaction conditions. Therefore, further study was performed using AlCl3 to estimate the effect of operating parameters and catalyst concentration over EL yield and HMF conversion. Thereafter, a comparative study on the effect of microwave vs non-microwave instant heating reaction environment has been done to develop a sustainable process for EL synthesis. Consequently, mechanistic insights on reactant conversion and product yield have been attempted to understand various pathways followed. Thereafter, effect of reaction temperature, catalyst loading, ethanol concentration and heating rates were explored. EL synthesis from HMF under instant heating reaction conditions in the presence of metal salts is reported for the first time. We anticipate that present work would be helpful in providing insights on effects of instant heating method and operating conditions for EL synthesis from HMF.