GB670721A - Improvements in or relating to linear copolymers of the polyamide type and processesof preparing the same - Google Patents

Abstract

Resinous copolymers of the polyamide type are obtained by heating in the liquid phase a mixture of an anhydride of an N-carboxyl alpha-amino acid and an o -amino acid having at least 6 carbon atoms in the molecule. The N-carboxyl anhydrides have the formula <FORM:0670721/IV (a)/1> where R is hydrogen or a monovalent alkyl, aryl, or alkylaryl radical which may contain a carboxy or amino group if that group is protected by esterification. Examples of the acids from which the anhydrides are derived are glycine, alanine, leucine, norleucine, phenylalanine, tyrosine, diiodotyrosine, thyroxine, tryptophane, aspartic acid, glutamic acid, arginine and lysine. Examples of suitable amino acids are 11-amino undecanoic or undecylic acid, 10-amino decanoic or decylic acid, 10-amino decanoic or decylic acid. In examples: (1) 100 parts 11-amino undecylic acid and 80 parts e -N-carbobenzoxy-a -carboxyl lysine anhydride are mixed and melted in an oil bath kept at 210 DEG C. A viscous mass was obtained which was purified by solution in benzyl alcohol and precipitation with methanol. 50 parts of the copolymer were dispersed in 200 parts glacial acetic acid and hydrogen bubbled therethrough, 100 parts phosphonium iodide were added and the reduction continued for two hours. The semi-solid obtained after purification was soluble in glacial acetic acid; (2) 33 parts N-carboxyl phenylalanine anhydride and 67 parts 11-amino undecanoic acid were heated for 1 hour at 200 DEG C.; (3) 11-amino undecanoic acid and N-carboxyl-glycine anhydride were similarly reacted. The Specification as open to inspection under Sect. 91 states that the N-carboxyl amino acids themselves or their derivatives may be used instead of their anhydrides. This subject-matter does not appear in the Specification as accepted.