Design and synthesis of SO3H-functionalized acidic ionic liquids for catalytic conversion of wheat straw to ethyl levulinate

Ethyl levulinate (EL) is a key platform compound for the catalytic conversion of biomass. Ionic liquids (ILs) have attracted much attention due to their unique tunable structures and wide range of applications, a series of SO3H-functionalized imidazole based acidic ILs were designed and synthesized. These SO3H-functionalized ILs were used as the catalyst to be applied to the conversion of the wheat straw to EL. Among them, SimIL-6 exhibited good catalytic performance for the conversion of wheat straw to EL in ethanol. When the concentration of SimIL-6 was 30 mmol/L, the yield of EL could reach 20.1 wt% at 180 celcius for 2 h. Furthermore, SimIL-6 as the catalyst was reused at least six times without significant reduction in catalytic efficiency. This work shed light on a new approach towards the full utilization of biomass and efficient degradation of biomass to EL.