| 摘要 |
<p>In the production of maleimides of the general formula I ( I ) in which n is one of the numbers 1, 2 or 3, Rl and R2 are each a hydrogen atom or methyl, ant A is an n-valent aliphatic, cycloaliphatic, aliphatic-cycloaliphatic or aliphatic-aromstic radical having up to 30 C atoms, by means of cyclising dehydration of a maleamic acid of the formula II (II) in which the acid amide group(s) is (are) attached to aliphatic or cyoloaliphatic C atoms, in the presence of low-molecular dehydratingcarboxylic anhydrides in an organic solvent and in the present of catalysts, there 18 advantageously used as solvent a polar aprotic solvent containing at least one N-lower-alkyl-substituted acid amids group in the molecule, or a solvent mixture containing an aprotic solvent of this type, and as catalyst a metal compound, and the cyclising dehydration is performed in the temperature range of 40 to 100.degree.C.</p> |
