反应详情

There are already various methods for the production of N-phenylmaleimide. Of these processes, the one which produces N-phenylmaleimide in two steps, starting from maleic anhydride and aniline, has been the subject of the greatest number of research work in recent years. In this process, maleic anhydride is first reacted with aniline at moderate temperature, to form maleanilic acid in an almost quantitative yield. Then the maleanilic acid, which may or may not be separated from the reaction medium, is subjected to thermal dehydration at elevated temperature in a water-immiscible organic solvent capable of forming an azeotrope with water, such as toluene, xylene, chlorobenzene and in the presence of an acid catalyst, such as for example sulfuric acid, phosphoric acid and the like, the water formed in the course of the reaction being removed by azeotropic distillation.