Intensified ethyl levulinate production from cellulose using a combination of low loading H2SO4 and Al(OTf)3

Mixed-acid system consisting of Bronsted and Lewis acids as an innovative strategy for directly converting cellulose in ethanol medium was conducted to improve the production of ethyl levulinate (EL). A combination of low loading H2SO4 (0.01 mol/L) and Al(OTf)(3) (0.002 mol/L) was found to be an efficient catalyst system for this reaction, affording an optimum EL yield of 64.9% at 180 degrees C for 3 h. A possible synergistic catalytic mechanism was proposed based on the reactivity of various carbohydrates. The developed mixed-acid catalyst system was further extended to the direct transformation of real cellulosic biomasses for the synthesis of EL.