| 摘要 |
PURPOSE:To safely obtain a maleimide in high yield, by cyclizing and imidating a maleinamic acid in the presence of a metal-containing compound and stabilizer in an organic solvent capable of forming an azeotropic mixture with water within a specific temperature range while removing the formed water as the azeotropic mixture to the outside of the system. CONSTITUTION:A maleinamic acid expressed by the formula (R is alkyl, phenyl, pyridyl, etc.) is cyclized in the presence of 10-30mol%, based on the raw material, acid catalyst, e.g. sulfuric acid or pyrophosphoric acid, a metal-containing compound, e.g. Zn, Cr, Pd or Al, and stabilizer, e.g. methoxybenzoquinone, in an organic solvent capable of forming an azeotropic mixture with water, e.g. benzene or octane, while heating at 170-250 deg.C for 1-15hr to afford the aimed maleimide. The formed water is removed to the outside of the system by azeotropic distillation. USE:A raw material for resins, medicines and agricultural chemicals. |
