Efficient microwave-assisted production of biofuel ethyl levulinate from corn stover in ethanol medium

Abstract

Levulinate esters are versatile chemicals that have been used in various fields. Herein, the production of ethyl levulinate (EL) from corn stover was investigated under microwave irradiation. Several reaction parameters, including acid concentration, reaction temperature, reaction time, and liquid-to-solid mass ratio, were investigated to evaluate the reaction conditions. Response surface methodology (RSM) was employed to optimize the reaction conditions for the production of EL. A quadratic polynomial model was fitted to the data with an R2 value of 0.93. The model validation results reflected a good fit between the experimental and predicted values. A high conversion yield (58.1 mol%) was obtained at the optimum conditions of 190 °C, 30.4 min, 2.84 wt% acid, and 15 g/g liquid-to-solid mass ratio. Compared with conventional heating, microwave irradiation facilitated the conversion of corn stover to EL by dramatically shortening the reaction time from several hours to ∼30 min. Thus, microwave-assisted conversion of corn stover to EL is an efficient way of utilizing a renewable biomass resource.