Aqueous Choline Chloride/γ-Valerolactone as Ternary Green Solvent Enhance Al(III)-Catalyzed Hydroxymethylfurfural Production from Rice Waste

A ternary green solvent gamma-valerolactone (GVL)/choline chloride (ChCl)/H2O system is used to convert rice waste to hydroxymethylfurfural (HMF) using AlCl3 center dot 6H(2)O as a catalyst. The effect of the reaction time, temperature, substrate, catalyst, and catalyst amount on the extraction of HMF by GVL is studied under this system. The results show that in ChCl/H2O, GVL/H2O, and GVL/ChCl/H2O systems, the HMF yield reaches the highest levels of 8.21, 12.24, and 18.60 mol% after reaction at 140 degrees C for 1 h, respectively. The yield of HMF obtained by reacting 0.42 mmof AlCl3 center dot 6H(2)O at 140 degrees C for 30 min is significantly higher than that of CrCl3 center dot 6H(2)O and FeCl3 center dot 6H(2)O. After reaction at 140 degrees C for 5 min, the extraction rate of HMF by GVL reaches more than 80%. The aqueous solution of ChCl forming the ternary system has high recyclability, and after six times, the yield loss of HMF is small.