Patent GB-871578-A (GB)
Title: Improvements in or relating to the production of polyamides
IPC: C09D5/25
Filed: 1958-02-28
Abstract: An aromatic polyamide having an inherent viscosity in concentrated sulphuric acid at 30 DEG C. of at least 0,6 and a melting point of at least 300 DEG C. is made by reacting at a temperature below 100 DEG C. a diamine component containing at least 90 mol per cent of an aromatic diamine, any remainder being non-aromatic diamine, and a diacid halide component containing at least 90 mol per cent of an aromatic diacid halide, any remainder being non-aromatic diacid halide, the amine groups in the aromatic diamine and the acid halide groups in the aromatic diacid halide not being ortho-oriented with respect to each other or to bonds linking one aromatic ring directly or through a linking group to another aromatic ring, the substituent groups (if any) in the aromatic rings being groups which do not react with the amine or acid halide groups during polymerization and the total number of carbon atoms in substituent groups attached to any one aromatic ring not exceeding nine, in the presence of an organic acid-acceptor, in a liquid reaction medium which is a solvent for each of the reactants and the acid-acceptor and which has an average solvent/solute interaction energy with complementary model compounds representative of the polyamide less than 1100 calories per mole. The term organic "acid-acceptor" is defined as being a compound which will effectively remove acidic by-products of the reaction without itself interfering with the polymerization and containing at least one organic carbon atom. The liquid reaction medium may also function as the acid-acceptor. The model compounds are diamides free from polyamide-forming terminal groups and having specified formulae.  The Specification lists large numbers of aromatic diacid halides and aromatic diamines which may be used in the process of the invention. Specified solvents include chloroform, methylene chloride, 1, 1, 2-trichloroethane, 1, 2-dichloroethane, methyl ethyl ketone, acetonitrile, tetramethylene sulphone and propionitrile. Specified solvents which act as acid-acceptors include dimethyl acetamide, N, N, N1, N1-tetramethyl urea and N-ethyl pyrrolidone.  The examples describe the preparation of polyamides from: (1) m-phenylene diamine hydrochloride and isophthaloyl chloride, (2) and (8) 4-methyl-m-phenylene diamine and isophthaloyl chloride, (3), (5), (6), (14), (15) and (20) to (25) m-phenylene diamine and isophthaloyl chloride, (4) bis-(4-aminophenyl) methane and isophthaloyl chloride, (7) m-phenylene diamine and 4-chloro-isophthaloyl chloride, (9) 4-methoxy-m-phenylene diamine and isophthaloyl chloride, (10) m-phenylene diamine, isophthaloyl chloride and terephthaloyl chloride, (11) m-phenylene diamine hydrochloride, p-phenylene diamine hydrochloride and isophthaloyl chloride, (12) terephthaloyl chloride and m-phenylene diamine, (13) 4, 41-sulphonyl-diphenyl-diamine or 2, 21-bis(4-aminophenyl) propane and isophthaloyl chloride, (16) m-phenylene diamine and terephthaloyl chloride, (17) 2, 2-bis(4-aminophenyl) propane and isophthaloyl chloride, (18) p-phenylene diamine and isophthaloyl chloride and (19) p-phenylene diamine and terephthaloyl chloride in the presence of: (1) triethylamine hydrochloride and methylene chloride, (2), (6), (7) and (8) triethylamine, triethylamine hydrochloride and methylene chloride, (3) tetramethylene sulphone and N-methyl morpholine, (4) dimethyltetramethylene sulphone and diethylanaline, (5) chloroform, triethylamine and triethylamine hydrochloride, (9), (10) and (11) methylene chloride and triethylamine, (12) dimethyltetramethylene sulphone and triethylamine, (13) tetramethylene sulphone and dimethylacetamide, (14), (16) and (17) dimethyl acetamide, (15) N-methyl-a -pyrrolidone, (18) N, N, N1, N1-tetramethyl urea, (19) hexamethyl phosphoramide, (20) N-acetyl pyrrolidone, (21) N, N-tetramethylene-N1, N1-dimethyl urea, (23) triethylamine and N-methyl pyrrolidone, (24) triethylamine and dimethyl cyanamide and (25) triethylamine, triethylamine hydrochloride and acetonitrile. The products are soluble in dimethyl formamide or dimethyl acetamide and may be extruded into filaments or formed into films. Specification 871,581 and U.S.A. Specification 2,831,834 are referred to.