Methacrylic acid dimer

Abstract In the preparation of methyl methacrylate by the acetone cyanhydrin‐methacrylamide route, a dimeric ester is formed as a by‐product, and can be isolated in amounts corresponding to about 1 % theoretical. The acid obtained by saponification of the dimeric ester has been shown to be α δ;‐dimethyl‐α β‐hydromuconic acid. Investigations made at points in the methyl methacrylate synthesis indicate that the dimeric acid is formed (as amide) by dimerisation of methacrylamide under the influence of the sulphuric acid present.