| 摘要 |
<p>PURPOSE:To obtain the titled compound in high yield, by heating a maleinamidic acid in a specific inert organic solvent in the presence of an acid catalyst to effect cyclizing imidation of the acid and, after completion of the reaction, separating and recovering the acid catalyst from the organic solvent layer and recycling to the above reaction stage. CONSTITUTION:A maleimide compound is produced by the thermal cyclizing imidation of a maleinamidic acid of formula (R is 1-20C alkyl, phenyl, benzyl, etc.; preferably alkyl or phenyl) in a water-insoluble or water-immiscible inert organic solvent such as benzene, toluene or a petroleum fraction having a boiling point of 50-120 deg.C in the presence of an acid catalyst such as sulfuric acid, sulfuric anhydride, p-toluenesulfonic acid, etc. In the above process, the acid catalyst is separated and recovered from the organic solvent layer after completion of the reaction and the recovered catalyst layer is recycled to the above reaction stage and reused. The objective compound can be produced in high purity at a low cost with a simple process.</p> |
