| 摘要 |
PURPOSE:To produce an N-substituted maleimide in high yield and purity, economically on an industrial scale, by adding a specific amount of maleic acid to monoammonium maleate or maleic acid half-amide and carrying out the cyclizing dehydration at a specific temperature in the presence of super-heated steam. CONSTITUTION:100pts.wt. of monoammonium maleate or maleic acid half-amide is mixed with 1-50pts.wt., preferably 5-20pts.wt. of maleic acid which is noncorrosive to metallic material such as stainless steel, titanium, etc., and super-heated steam of 150-400 deg.C is introduced into the mixture to effect the cyclizing dehydration reaction. An N-substituted maleimide useful as a raw material of a heat-resistant polymer can be produced economically without using a dehydration agent. The corrosion of the production apparatus can be prevented in the present process because a dehydration agent is not used, and a metallic material such as stainless steel, titanium, etc., can be used in place of glass. The product can be used for other purposes without further purification.
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