Phosgene method

The phosgene method is the earliest industrial method for preparing ethylene carbonate. This process uses ethylene glycol to react directly with phosgene. Because phosgene is highly toxic and causes serious pollution to the environment, this method has been banned in developed countries.

Transesterification method

The method of preparing ethylene carbonate EC by the transesterification reaction of diethyl carbonate and ethylene glycol is the transesterification method. Dibutyltin dilaurate and a trace amount of strong base are used as catalysts for the transesterification reaction, and ethanol is continuously distilled out at the reaction temperature of the xylene reflux control system. To reduce the loss of diethyl carbonate in the process of evaporating ethanol, increase the reaction temperature of the system and accelerate the reaction speed. Then directly add p-toluenesulfonic acid to neutralize and catalyze the prepolymerization reaction. The generated oligomers are catalyzed by high-efficiency cracking catalyst tin powder and depolymerized at high temperature to obtain cyclic carbonate.

Ethylene oxide and carbon dioxide addition method   

The preparation of ethylene carbonate by the addition reaction of ethylene oxide and carbon dioxide is an exothermic and volume-reducing reaction. From the perspective of chemical equilibrium, low temperature and high pressure conditions are conducive to the reaction. At the same time, the selection of a suitable catalyst is the key to whether the reaction can proceed smoothly. The systems of this reaction mainly include homogeneous catalytic systems and heterogeneous catalytic systems.