Synthesis of Ethylene Glycol via Hydrolysis of Ethylene Carbonate Catalyzed by Immobilized Ionic liquid

The SiO2 immobilized ionic liquid catalyst S-[bpim]Br was prepared through sol-gel method. By treatment of S-[bpim]Br with potassium hydrogen carbonate, S-[bpim][HCO3] was obtained. Then, the catalytic activity of SiO2 immobilized ionic liquid in the synthesis of ethylene glycol (EG) via hydrolysis of ethylene carbonate (EC) was studied. The results showed that the immobilized basic ionic liquid S-[bpim][HCO3] exhibited good performance on the hydrolysis of ethylene carbonate and could be separated easily from the reaction system. Moreover, the effects of temperature, molar ratio of EC to H2O, reaction pressure, reaction time, and content of catalyst were also investigated in detail. The optimal reaction conditions were determined as follows: reaction temperature 140℃, reaction pressure 0.4 MPa, molar ratio of water to ethylene carbonate 2:1 and reaction time 3 h. Under above conditions, 99.7% EC conversion rate and 100% EG selectivity were obtained. Additionally, the catalyst could be reused at least 5 times with slight loss of its activity.