Patent GB-825096-A (GB)
Title: Linear polyamides
Inventor: BROWN KENNETH GORDON
IPC: C08G69/02
Filed: 1957-03-27
Abstract: 2 : 5 - Di - (b  - carboxyethyl) - p - xylene is made by heating dimethyl terephthaldehyde, malonic acid and pyridine in the presence of piperidine to produce p-xylene-2 : 5-di-(b )-acrylic acid which is hydrogenated and the resultant 2 : 5-di-(b -carboxyethyl)-p-xylene precipitated by addition of hydrochloric acid and purified by formation of the methyl ester in the presence of dry hydrogen chloride.  2 : 5 - Di - (b  - aminoethyl) - p - diethyl benzene is made by converting p-diethyl benzene to 2 : 5-di-chloromethyl-p-diethyl benzene by reaction with paraformaldehyde and gaseous hydrogen chloride, the chlorine groups then being replaced by cyano groups by reaction with sodium cyanide in aqueous b -ethoxyethanol and the product reduced to 2 : 5-di-(b -aminoethyl)-p-diethyl benzene by hydrogen and methanolic ammonia. 2-b -Carboxyethyl-5-carboxymethyl-p-xylene is made by hydrogenating 2 : 5-dimethyl cinnamic acid in the presence of palladium on charcoal to yield b -2 : 5-dimethyl phenyl propionic acid which is esterified with ethanol and sulphuric acid and chloromethylated by chloromethyl ether and stannic chloride to yield 2-b -carbethoxy ethyl-5-chloromethyl-p-xylene which is reacted with aqueous ethanolic sodium cyanide and hydrolised to 2-b -carboxyethyl-5-carboxymethyl-p-xylene.  Specification 627,733 and U.S.A. Specification 2,640,080 are referred to.ALSO:High molecular weight synthetic linear polyamides are made by heating a durene derivative wherein the durene carries on the 1 and 4 or 1 and 5 methyl groups two of the following substituents, namely aminomethyl, carboxy and carboxymethyl, or polyamide-forming functional derivatives of said substituents, the other methyl groups optionally bearing one methyl group, with an aliphatic diamine or an aliphatic dicarboxylic acid respectively according as the durene derivative contains two carboxy or two amino groups, with the proviso that no aliphatic diamine or acid is required when the durene derivative contains both an amino and a carboxy group, but additional polyamide-yielding reagents may be used if interpolyamides are desired.  Specified durene derivatives are 2:5 - di(carboxymethyl) - p-xylene, 2:5 - di(b  - carboxyethyl) - p - xylene, 2:5 - di(b  - aminoethyl) - p - xylene, 4:6 - di(b -carboxyethyl) - m - xylene, 4:6 di(aminoethyl) - m - xylene, 4:6 - di(carboxymethyl)-m - xylene, p 2:5 - di(b  - aminoethyl) - p - diethyl benzene, 2 - b  - aminoethyl - 5 - carboxyethyl-p - xylene and 2 - b  - carboxyethyl - 5 - carboxymethyl-p-xylene.  Specified aliphatic diamines are hexamethylene diamine, 3-methyl hexamethylene diamine, tetramethylene diamine, decamethylene diamine, octamethylene diamine, ethylene bis-(3-aminopropyl)-ether, 1:6 - diamino - 6 - methyl heptane and N:N1-dimethyl hexamethylene diamine.  Specified aliphatic dicarboxylic acids are adipic, b -methyl adipic, sebacic, glutaric, pimelic and hexadecamethylene dicarboxylic acid.  Specified functional derivatives are the N-formyl derivatives of the amines and the ethyl esters of the acids.  Viscosity stabilizers, e.g. acetic acid and dyes, pigments and plasticizers may be incorporated in the reactants.  The examples describe the manufacture of polyamides from: (1) decamethylene diamine and 2:5-di(carboxymethyl)-p-xylene; (2) decamethylene diamine and the dimethyl ester of 2:5-di-(b -carboxyethyl)-p-xylene; (3) hexamethylene diamine and 2:5-di - (b  - carboxyethyl) - p - xylene; (4) the sebacic acid salt of 2:5-di(b -aminoethyl)-p-xylene; (5) the pimelic acid salt of 2:5-di(b -aminoethyl) - p - xylene; (6) the b  - methyl adipic acid salt of 2:5-di-(b -aminoethyl)-p-xylene; (7) the adipic acid salt of 2:5-di-(b -aminoethyl) - p - xylene; (8) the adipic acid salt of 4:6-di(b -aminoethyl)-m-xylene; (9) mixtures of the salts used in Examples (7) and (8); (10) the sebacic acid salt of 2:5-di(b -aminoethyl)-p-xylene and hexamethylene diammonium adipate; (11) the decamethylene dicarboxylic acid salt of 2:5-di(b -aminoethyl)-p-xylene; (12) the adipic acid salt of 2:5-di(b -aminoethyl)-p-diethyl benzene; (13) the sebacic acid salt of 2:5-di(b -aminoethyl)-p-xylene; (14) the hexamethylene diamine salt of 2-b -carboxyethyl - 5 - carboxymethyl - p - xylene; and (15) 2-b -aminoethyl-5-b -carbethoxyethyl-p-xylene. The products of Examples (1), (4), (5), (10), (11) and (13) are spun into filaments. Specification 627,733 and U.S.A. Specification 2,640,080 are referred to.