Acid–Base Synergistic Catalysis Over Zn/ Al Layered Double Oxides Toward the Hydrolysis of Ethyl Carbonate Under Mild Conditions

Among many ethylene glycol (EG) synthetic methods, the ethylene carbonate (EC) route is preferred due to its extremely high EG selectivity and low H2O/EC ratio. In this work, a variety of layered double hydroxides (LDHs) and layered double oxides (LDOs) were synthesized by the co-precipitation method and evaluated as catalysts for this reaction. The Zn3Al-LDO showed the highest catalytic activity under low H2O/EC ratio and mild conditions, and the EG yield of 93 %-99 % could be obtained at 100 degrees C for 3-4 h. This superior performance is attributed to the absence of the "memory effect", allowing Zn3Al-LDO to retain a significant number of base sites in the hydrolysis system. The active sites inhibition experiment proved that Zn3Al-LDO is an acid-base synergistic catalyst and the base sites are dominant. The catalyst can be recycled at least five times with calcination and activation to maintain excellent catalytic activity.