Breakthrough Achieved by Commercial Demonstration Unit for Manufacture of 50 kt/

On July 18, 2020 the unit for production of propylene carbonate through reaction of urea with 1,2-propylene glycol, a key process of the dimethyl carbonate commercial demonstration project, has been put on stream. This first in the world 50 kt/a dimethyl carbonate commercial demonstration project owned by the Shanxi Zhongke Huian Chemical Company, Ltd. was designed by the Dalian Chemical Industry Design Institute using the core technology licensed by the Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences.

After 100 hours of continuous and smooth operation,this unit had reached a 100 % rate of urea conversion,while at the same time achieving a single-pass propylene carbonate yield of over 90%, a propylene carbonate purity of ≥99.95% (by weight), and a liquid ammonia purity of ≥99.9% (by weight), denoting that the large-scale dissemination of the technology for indirect production of dimethyl carbonate through reaction of urea with methanol is feasible.

Currently the industry practice mainly uses transesterification or oxidative carbonylation of methanol to produce dimethyl carbonate. The former uses the petroleum processing downstream product as the feedstock such as propylene oxide or ethylene oxide to manufacture propylene carbonate or ethylene carbonate, which is then converted to dimethyl carbonate through transesterification with methanol; the latter uses methanol, NO, CO,and oxygen as the feedstocks to manufacture dimethyl carbonate through the methyl nitirte step.

Upon using urea and methanol as the feedstocks, this project by reacting urea with 1,2-propylene glycol can produce liquid ammonia and propylene carbonate,which can further react with methanol to yield dimethyl carbonate coupled with a by-product 1,2-propylene glycol that can be used to produce propylene carbonate.This technology features low cost and easy availability of raw materials, mild reaction conditions, clean production with excellent environmental friendliness,and low production cost, which can serve as one of the transformation and upgrading projects attracting the top attention of China’s urea and coal chemicals industry for a long time.