Preparation of N-substituted oligo-imides

Abstract

N-substituted oligo-imides of the formula: ##STR1## in which D represents a divalent radical selected from the group comprising: ##STR2## in which m is 0 or 1, Y is hydrogen, chlorine or methyl, n is a positive integer of 5 or less, and R is an organic radical of valency n, containing up to 50 carbon atoms, are prepared by reacting an anhydride of the formula: ##STR3## with an amine of the formula: R--NH.sub.2).sub.n [III] in which formulae D, R, and n as above defined, said reaction being carried out in the presence of a catalyst system comprising a mixture of a compound (.alpha.) and a compound (.beta.), being a strong inorganic or organic oxygen-containing acid and (.beta.) being a salt of such acid with a cation selected from the group comprising pyridinium, quaternary phosphonium and tertiary sulfonium cations.

Dependencies are inferred from the claim text.