Catalytic Conversion of Cellulose into 5-Hydroxymethylfurfural Using [PSMIM]HSO 4 and ZnSO 4 ·7H 2 O Co-catalyst in Biphasic System

Production of 5-hydroxymethylfurfural (HMF) from microcrystalline cellulose (MCC) was studied in 1-(3-sulfonic acid)-propyl-3-methylimidazolium hydrogen sulfate ([PSMIM]HSO 4 )–H 2 O/THF biphasic system with catalytic amount of ZnSO 4 ·7H 2 O. The effects of various reaction parameters such as catalyst charge, reaction temperature and the volume ratio of water to tetrahydrofuran were investigated. The highest HMF yield of 58.8 % and TRS yield of 64.8 % were obtained at 160 °C for only 60 min by [PSMIM]HSO 4 and ZnSO 4 ·7H 2 O as co-catalyst. A possible mechanism was proposed to explain the high activity of [PSMIM]HSO 4 and ZnSO 4 ·7H 2 O as co-catalyst. After being separated from the organic phase, the aqueous phase could be reused and demonstrated stable activity after four successive runs.