Dimethyl carbonate (DMC) is one of the most important chemicals, which has a wide application range. It is used as the raw material of polycarbonate (PC) plastics, the solvent of electrolyte for energy storage devices, the additives of diesel fuel, etc. The worldwide carbonate synthesis industry is currently dominated by the transesterification method with ethylene oxide as a starting material, which was commercialized in the 1990s. However, the starting material, ethylene oxide, is from the crude oil and causes environmental pollution during production, so recently, the synthesis of carbonate based on urea has attracted attention.
At present, the achievement on the synthesis of DMC from urea and alcohol mainly comes from the research on catalysts and the most widely-used catalyst is ZnO. The reaction of DMC synthesis using ZnO as a catalyst proceeds according to the heterogeneous catalytic mechanism. However, to date, the ZnO catalyst used in previous studies is mostly prepared by the sol-gel method.
Preceding studies imply that 4-needle like nano-ZnO demonstrates stronger catalytic activity than spherical or sheet ZnO crystals, which improves reactions.
On the basis of the analysis, Kim Myong Hyok, a researcher at the Faculty of Chemical Engineering, studied the catalytic use of 4-needle like nano-ZnO prepared by the combustion method to improve the reaction time and temperature of dimethyl carbonate (DMC) synthesis, and the catalyst recovery, aiming to improve the DMC yield.
48g of methanol and 1g of catalyst were put into the reactor and heated to the desired reaction temperature, and then a liquid mixture of methanol 80g and urea 12g was added to the reactor for 10min. Ammonia generated during the reaction was removed three times through the safety valve of the reactor.
When nano-ZnO was used as a catalyst, the optimum reaction time and temperature of the DMC synthesis reaction were 3h and 140℃, respectively, with a DMC yield of 65.1%. The catalyst was recycled up to seven times.
You can find the details in his paper “Improvement in the Yield of Dimethyl Carbonate by 4-Needle like Nano-ZnO”in “Proceedings of KUTIC-2025”.