POLYQUINAZOLINES AND THEIR METHOD OF MANUFACTURE

1343288 Polyiminochlorides OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AEROSPATIALES 20 Nov 1970 [21 Nov 1969] 38035/73 Divided out of 1343287 Heading C3R Polyiminochlorides in which the recurring unit contains at least one group of the general formula in which the aromatic nucleus is an arylene radical which is unsubstituted or substituted by one or several C 1-5 alkyl, C 1-5 alkoxy radical(s), halogen atom(s) or nitro radical(s), at least one of the ortho positions of the aromatic nucleus vis-a-vis the direct linkage with the nitrogen atom being unsubstituted, may be prepared by reacting the corresponding polyamide with an acid chloride, e.g. PCl 5 or SOCl 2 preferably in the presence of a volatile inert solvent at 80‹-120‹ C. A preferred polyiminochloride comprises recurring units of the formula where X represents a direct linkage or a bivalent radical such as -O-, -CH 2 -, -SO 2 -, -CO- or -S-. The polyiminochlorides can be used in the production of polyquinazolines as described in the parent Specification by reaction with nitriles, in which case the reaction of the amide with the acid chloride preferably takes place in the presence of a Lewis acid type catalyst. In the examples polyiminochlorides are prepared from the following polyamides using PCl 5 as acid chloride: (1) poly(diphenyletherisophthalamide): (2) polybiphenylisophthalamide); (3) poly(diphenylmethaneisophthalamide); (4) poly(diphenylsulphoneisophthalamide), (5) (polydiphenyletherterephthalamide), (6) poly(biphenylterephthalamide), (7) poly(diphenylmethaneterephthalamide); and (8) poly- (diphenylsulphoneterephthalamide), using nitrobenzene as solvent. The polyiminochlorides can be isolated from the solvent.