Versalis/CB&I's methyloxycarbonylation technology is based on a single-step liquid-phase cuprous chloride-catalyzed process originally developed by Polymeri/EniChem. Versalis was created as a subsidiary of Polymeri/EniChem or changed its name. CB&I is your partner in contract licensing and engineering. Our assessment of the technology is based on a single-train plant producing approximately 25,000 metric tonnes per annum (MTPA) of DMC. The chemical composition of the process is simple, but produces small amounts of corrosive by-products, so glass-lined materials must be used for some equipment. overall

IHS Chemistry | PEP Report 301 dimethyl carbonate
According to IHS estimates, the yield of DMC is 91.9% (calculated as methanol). Versalis/CB&I produces DMC primarily for the commodity market.
Ube's methanol oxycarbonylation technology is based on a two-step (or indirect) gas-phase palladium-copper chloride catalyzed process. There are some more complex chemical reactions to this process. In the first stage, methyl nitrite (MN) is carbonylated in a fixed bed reactor to form DMC and nitric oxide (NO). In the second step, NO reacts noncatalytically with oxygen and methanol to form MN and water. The MN is recycled into the first step. Therefore, essentially only CO, O2 and methanol are consumed in the process. The overall yield of DMC was 92.5% (calculated as methanol). Ube's process is somewhat more expensive in terms of capital costs than Versalis/CB&I's process, according to IHS estimates. However, the cost of DMC produced by the two processes is very close, mainly because the Ube process also produces dimethyl oxalate by-product, which improves the economy of the process. Ube produces DMC primarily to sell it on the commodity market.
Our third technical analysis is the production of DMC by the urea transesterification process using methanol. Since this process is not yet commercialized, a general type of analysis is provided based on the data presented in the Catalytic Distillation Technology (CDTECH) patent. Urea-methanol conversion to DMC occurs in two steps - first, urea is converted to methyl carbamate (MC) by reaction with methanol at relatively low temperatures (e.g., 100°C, or 150°C in the presence of a catalyst) °C without catalyst); then, the carbamate is further reacted with methanol at 180-190°C in the presence of a catalyst to generate DMC.