PURPOSE: To obtain a maleimide at a low cost, by cyclizing and imidating a maleinamic acid in the presence of an acid catalyst in an organic solvent capable of forming an azeotropic mixture with water within a specific temperature range wile removing the formed water as a mixture thereof with the organic solvent 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 10W30mol%, based on the raw material, acid catalyst, e.g. sulfuric acid or pyrophosphoric acid, in an organic solvent capable of forming an azeotropic mixture with water, e.g. benzene or octane, while heating at 200W250°C for 1W15hr 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.
SAKAMOTO KENTARO
BABA MASAO
| JPS5368770A | 1978-06-19 | |||
| JPS5140078A | 1976-04-03 |