【Ten Years of Great Progress in Chemical Technology】190-2020: The First Industrial Demonstration Project for the Indirect Production of Dimethyl Carbonate from 50,000 Tons of Urea and Methanol

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Ten years of rapid development in chemical technology; praise for the prosperous and strong China. This is just a starting point to encourage more participation from everyone. HaiChuan becomes even better with your involvement – we welcome all to join in the forum discussions. With the hot weather in July, be careful to prevent fires. ------------------------------------------- Powered by core technology provided by the Shanxi Coal Chemistry Institute of the Chinese Academy of Sciences, designed by Dalian Chemical Engineering Design Institute Co., Ltd., the world’s first industrial demonstration project capable of producing 50,000 tons per year of dimethyl carbonate through the indirect synthesis of urea and methanol was built by Shanxi Zhongke Hui’an Chemical Co., Ltd. in Tunliu District, Changzhi City, Shanxi Province. The key process in this project – the reaction of urea with 1,2-propanediol to produce propylene carbonate – began operational trials on July 18, 2020. After 100 hours of continuous and stable operation, the established targets were achieved: a urea conversion rate of 100%, a one-pass yield of propylene carbonate greater than 90%, a purity of propylene carbonate of ≥99.95 wt%, and a purity of liquid ammonia of ≥99.9 wt%. This indicates that several key technical bottlenecks in the scale-up of the process for indirectly producing dimethyl carbonate from urea and methanol have been overcome, making large-scale application feasible. Dimethyl carbonate is an emerging non-toxic or slightly toxic chemical product that can replace highly toxic or carcinogenic substances such as phosgene, dimethyl sulfate, chloromethane, methyl chloroform, benzene, toluene, xylene, Freon, trichloroethane, trichloroethylene, and chloroform in organic synthesis or as a solvent. It is regarded as a \"new cornerstone of organic synthesis\" and a \"green solvent that combines cleanliness and safety\". At the same time, dimethyl carbonate is also an effective additive for gasoline/diesel fuels and a **agent, and it is an essential and efficient component in the electrolytes of new energy lithium-ion batteries. Currently, the transesterification method or methanol oxidative carbonylation method is primarily used in industry to produce dimethyl carbonate. Using propylene oxide or ethylene oxide as raw materials, propylene carbonate or ethylene carbonate is first produced; these compounds are then ester-exchanged with methanol to yield dimethyl carbonate ； The latter uses methanol, NO, CO, and O2 as raw materials to produce dimethyl carbonate via methyl nitrite. The method employed in this demonstration project uses urea and methanol as raw materials; urea is first reacted with 1,2-propanediol to produce propylene carbonate and liquid ammonia, which is then used together with methanol to produce dimethyl carbonate. The 1,2-propanediol generated as a by-product is recycled for the synthesis of propylene carbonate. This method offers advantages such as inexpensive and readily available raw materials, mild reaction conditions, environmental friendliness, and low costs; it has thus been one of the options for transformation and upgrading that the coal chemical industry in China, which is a major producer of urea and methanol, has been focusing on for many years.