Published November 2001
In late 1980s, Ube developed a new low-pressure vapor-phase technology to produce dimethyl carbonate (DMC). This technology produces DMC from methanol by oxidative carbonylation with dimethyl oxalate (DMO) as a by-product, and was commercialized in the early 1990s in Japan with an initial production capacity of 3,000 t/yr. This plant has been debottlenecked and expanded to 5,300 t/yr in 2000. DMC is an alternate material to phosgene in the production of polycarbonate, where it is converted to diphenyl carbonate (DPC) before the latter is incorporated into the polymer through transesterification process (or melt process).
Recently, this technology has been extended to a new direction to produce DPC from DMO via diphenyl oxalate (DPO).
This Review presents a technoeconomic evaluation of this new technology, based on available public information. Also presented is economic comparison between the present process and those of two other DPC processes - DPC from phenol by direct phosgenation and DPC from DMC by carbonylation. We conclude that the present process is not economic competitive to the latter two processes. Complexity of the present process causes high capital investment and high utility consumption, which result in high variable and fixed costs in DPC production. At the publication of this study, we have learned substantial improvement has been made in this process lately; we believe substantial reduction in capital investment and production could be realized to make this process economically competitive to the other two processes.