Process for the production of cyclic carboxylic acid imides

Claim 1

In a process for the production of an N-substituted cyclic carboxylic acid imide by reacting in a solvent at an elevated temperature between about 40°C. and 160°C. A. an ortho-dicarboxylic acid or its anhydride of the formula ##EQU3## wherein A is a divalent radical, selected from amongst phenylene, or phenylene substituted by halogen, nitro, acetamido, lower alkyl, lower alkoxy; tetrahydrophenylene or pyridylene: with B. a mono- or di-amine, selected from amongst alkylamine, alkylenediamine, N-alkyl substituted alkylenediamine of up to 18 carbon atoms; phenyl mono- or diamines which may be substituted by halo, nitro, hydroxy, mercapto, lower alkyl, lower alkoxy, mercaptomethyl, mercaptoethyl, methyl or ethyl carboxylate, sodium or potassium sulfonate, or 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyloxide, 4,4'-diamino diphenylsulfone, 1,5-diaminoanthraquinone, aminopyrazine, 2-aminopyridine, 2-aminothiazole, 2-amino-4-methylpyridine, 6-amino-3-methylpyridine, 2-amino-4-methylpyrimidine, ammeline, 2,6-diaminopyridine, 3-aminopyridine or 4-aminopyridine the improvement of carrying out said reaction in a liquid solvent mixture consisting essentially of a non-polar organic solvent and a strongly polar organic solvent which form a ternary azeotrope with water at the reaction temperature.