Abstract: In the production of an N-unsubstituted maleinimide by the ring-closing alcohol-removing treatment of an N-unsubstituted maleinamic ester for conversion into an imide, an acid catalyst or a mono(cyclo)alkyl sulfuric ester is used for the reaction. In this case, the alcohol concentration in the reaction solution is preferable to be adjusted to a low level. By using a maleinamic acid and an alcohol in conjunction with an inert solvent and an acid catalyst, a mixture of maleinamic acid with an acid catalyst, or a mono(cyclo)alkyl sulfuric ester, a corresponding maleinamic ester is obtained.

Abstract: The present invention is directed to an acrylonitrile maleimides solution composition of highly desirable shelf like, having the acid component in said acrylonitrile maleimides soltuion adjusted to a level of no more than 0.1% by weight based on the amount of said maleimides contained in said solution and having a polymerization inhibitor in said solution adjusted to a level in the range of 0.0001 to 1% by weight based on the amount of said solution, and a method for the production thereof.

Abstract: A method for the production of a maleimide, which comprises effecting a former-stage reaction by adding maleic anhydride and a primary amine in amounts such that the molar ratio of said maleic anhydride to said primary amine is less than 1 under application of heat to a water-insoluble or water-immisible inert organic solvent containing an acid catalyst and subsequently carrying out a latter-stage reaction by adding to the reaction system maleic anhydride in an amount such that the molar ratio of the total amount of maleic anhydride to be added to said reaction system to the total amount of said primary amine added to said reaction system exceeds 1.