PROCESS FOR PREPARING AROMATIC BISMALEIMIDES

摘要

The invention relates to a process for preparing aromatic bismaleimides by cyclodehydrating the bismaleamic acid prepared in situ by the reaction between an aromatic primary diamine and a maleic anhydride, said process consisting of the preparation of intermediate bismaleamic acid by reacting the diamine with maleic anhydride at a temperature of 10...30°C followed by cyclodehydration in the presence of an acid catalyst in a ratio of 0.05...0.12 moles/mole of aromatic primary diamine, in a reaction medium consisting of toluene and dipolar aprotic solvent, and of the distillation of the toluene in the reaction mass and the precipitation of the aromatic bismaleimide formed with aliphatic alcohol, in a weight ratio bismaleimide : aliphatic alcohol of 1 : 3...5.