Catalytic conversion of cellulose to 5-hydroxymethyl furfural using acidic ionic liquids and co-catalyst

Efficient catalytic conversion of microcrystalline cellulose (MCC) to 5-hydroxymethyl furfural (HMF), is achieved using acidic ionic liquids (ILs) as the catalysts and metal salts as co-catalysts in the solvent of 1-ethyl-3-methylimidazo-lium acetate ([emim][Ac]). A series of acidic ILs has been synthesized and tested in conversion of MCC to HMF. The effect of reaction conditions, such as reaction time, temperature, catalyst dosage, metal salts, water dosage, Cu2+ concentration and various acidic ILs are investigated in detail. The results show that CuCl2 in 1-(4-sulfonic acid) butyl-3-methylimidazolium methyl sulfate ([C4SO3Hmim][CH3SO3]), is found to be an efficient catalyst for catalytic conversion of MCC to HMF, and 69.7% yield of HMF is obtained. A mechanism to explain the high activity of CuCl2 in [C4SO3Hmim][CH3SO3] is proposed. To the best of our knowledge, this report first proposes that the Cu2+ and [C4SO3Hmim][CH3SO3] show better catalytic performance in catalytic conversion of MCC to HMF.