Published July 1980
A variation in the isobutylene route to methyl methacrylate has been suggested by an Asahi Chemical patent for converting methacrolein directly to methyl methacrylate without producing methacrylic acid. Oxidation and esterification take place simultaneously in the liquid phase over a fixed bed of palladium lead catalyst. Selectivity of the reaction exceeds 95%.
An economic evaluation for a 250 million lb/yr MMA plant shows that the process simplification and high selectivity lead to slightly lower labor costs and lower capital investment than do methacrylic acid based processes. Low conversion, and the resulting large recycle for unreacted methacrolein and methanol solvent, leads to high steam consumption. The production costs and product value, therefore, are slightly higher than those of the methacrylic acid based processes.
The accuracy of our estimates do not permit differentiation among these processes; the product values are all significantly lower than the product value for MMA made by the established acetone cyanohydrin process.
