PURPOSE: To produce the titled compound in high conversion, without the problems of the corrosion of the apparatus and the troublesome operation to separate the catalyst, by isomerizing a maleic acid monoester using quaternary ammonium bromide and an organic peroxide as the isomerization catalyst, thereby enabling the reaction in a non-aqueous system.
CONSTITUTION: A fumaric acid monoester is produced by reacting a maleic acid monoester in the presence of an isomerization catalyst composed of a quaternary ammonium bromide and an organic peroxide, preferably in a non-aqueous system (in the absence of solvent or in an organic solvent) in nitrogen atmosphere at 50W120°C, preferably 60W110°C. The amount of the catalyst is 0.01W10pts.(wt.), especially 0.1W5pts. of the quaternary ammonium bromide and 0.01W10pts., especially 0.3W5pts. of the organic peroxide per 100pts. of the maleic acid monoester. In contrast with the reaction in an aqueous solution, there occurs no hydrolysis of the objective compound. Accordingly, the isomerization can be carried out in high yield, and the waste-water treatment step can be omitted.
MURATA TAKASHIGE
HARUTA YUKINORI
TAKEUCHI TOSHIHISA
