1-(1-Propylsulfonic)-3-methylimidazolium chloride acidic ionic liquid catalyzed hydrolysis of cellulose in water: Effect of metal ion co-catalysts

Abstract

The effect of eight metal ions, Cr3+, Mn2+, Fe3+, Co2+ Ni2+, Cu2+, Zn2+ and La3+ on 1-(1-propylsulfonic)-3-methylimidazolium chloride acidic ionic liquid catalyzed hydrolysis of cellulose in water was studied at 140–170°C. Mn2+, Fe3+, and Co2+ as co-catalysts produced significant enhancements in total reducing sugar (TRS) yields, with Mn2+ showing the highest activity. Mn2+ as co-catalyst produced 91.8, and 91.9% TRS yields, whereas samples without Mn2+ gave 28.0 and 28.7% yields at 160 and 170°C respectively. The observed activation energies for cellulose hydrolysis without a co-catalyst and with Mn2+ co-catalyst are 78.1±1.4 and 32.8±4.9kJ·mol−1 respectively.