Patent GB-667771-A (GB)
Title: Diamines and polyamides therefrom
IPC: C08G69/26
Filed: 1948-11-04
Abstract: Synthetic linear polyamides are prepared by heating diamines having the general formula <FORM:0667771/IV (a)/1> wherein Ar is an arylene radical selected from the class consisting of alkyl substituted and unsubstituted phenylene and biphenylene radicals and R is an alkyl radical having from 1-20 carbon atoms, with a dicarboxylic acid having, preferably, 3-20 carbon atoms between the carboxylic groups. The reaction mixture may contain minor amounts of other polyamideforming diamines, other dicarboxylic acids or polymerizable lactams such as capro-lactam; the polymeric products should preferably have at least 50 per cent of the amide groups derived from diamines of the above specified type.  The polymers have low water absorption and usually an intrinsic viscosity of at least 0.4 and a unit length of at least 7, as defined in Specification 461,236.  The polymers are soluble in methylene chloride, chloroform and chloroform-methanol mixtures and may be used in formation of textile fibres, bristles, moulding compositions, films including photographic films, and in water-proofing compositions of metals, fabrics and other materials.  The method of preparation may follow the procedure described in Specification 461,237.  In examples, polyamides are prepared from sebacic acid and p,p1-di-(1-aminoethyl) biphenyl, p,p1 di-(1-aminoisobutyl) biphenyl, p,p1-di-(1-aminopropyl)-m,m1-dimethyl biphenyl and p,p1-di-(1-amino-n-octadecyl) biphenyl, by reacting equimolar amounts of the appropriate diamine and sebacic acid in an alcoholic medium, isolating the resulting salt and in general heating it under a vacuum for several hours at 200-300 DEG  C.; instead of heating in vacuo the salt may be heated in an inert atmosphere.  The preparation of the diamines is described (see Group IV (b)).  Other starting materials mentioned are adipic, pimelic, suberic and terephthalic acids and 1,3,5-trimethyl-2,4-di-(1-aminoalkyl) - benzenes, 1,3,5 - trimethyl - 4-ethyl - 2,6 - di - (1 - aminoalkyl) - benzenes, 1,2,4,5 - tetramethyl - 3,6 - di - (1 - aminoalkyl)-benzenes and 1,3 - dimethyl - 2,5 - di - (1-aminoalkyl)-benzenes, and m,m1-dimethyl and other alkyl-substituted p,p1-(1-aminoalkyl)-bi-phenyls.  U.S.A. Specification 2,130,948 is referred to.  The Specification as open to inspection under Sect. 91 relates to the production of linear polyamides by reacting dibasic acids with diamines of the above general formula wherein Ar is any arylene radical.  This subject-matter does not appear in the Specification as accepted.ALSO:Diamines of the formula <FORM:0667771/IV (b)/1> where R is an alkyl radical of 1-20 carbon atoms and Ar is an arylene radical selected from the class consisting of alkyl-substituted or unsubstituted phenylene or bi-phenylene radicals, are prepared by catalytically hydrogenating in the presence of ammonia aromatic compounds containing two carbonyl groups, the carbon atom of each carbonyl group being directly bonded to the aromatic nucleus and to an alkyl radical, or by reacting the carbonyl compounds with hydroxylamine to convert said compounds into the corresponding dioximes and then catalytically reducing with hydrogen to the diamines.  The diamines may be used as intermediates for dyestuffs, pharmaceuticals, bactericides, insecticides, inhibitors and preservatives.  They are especially useful as starting materials for the production of linear polyamides (see Group IV (a)); they are reacted with dicarboxylic acids, especially those having 3-20 carbon atoms between the carboxyl groups, e.g. adipic, pimelic, suberic, sebacic and terephthalic acids, forming salts which are converted into linear polyamides on heating.  These polymers may be hydrolysed back to the diamines and dicarboxylic acids.  In examples: (1) p,p1-di-(1-aminoethyl) biphenyl is prepared by first reacting biphenyl with acetyl chloride in carbon bisulphide in presence of aluminium chloride, isolating the resulting p,p1-diacetyl biphenyl, converting it into the corresponding dioxime by reaction with hydroxylamine hydrochloride in aqueous ethanol to which sodium hydroxide is added with stirring, isolating the dioxime and reducing it in ethanol solution by means of hydrogen with the aid of Raney nickel; the diamine is reacted with sebacic acid in warm alcohol and the resulting salt filtered off and converted into a linear polyamide; (2) p,p1 - di - (1 - amino isobutyl) - biphenyl is prepared as in (1) starting from isobutyryl chloride and biphenyl, and the resulting diamine is similarly converted into the sebacic salt; (3) p,p1-di-(1-amino propyl)-m,m1-di-methyl biphenyl is prepared by reacting m,m1-dimethyl biphenyl with propionic anhydride in presence of carbon bisulphide and aluminium chloride, the resulting diketone being isolated and reduced to the diamine by means of hydrogen and ammonia in presence of alcohol and Raney nickel catalyst; the sebacic acid salt is formed as above; (4) p,p1-di-(1-amino-n-octadecyl)-biphenyl and its sebacic acid salt are prepared as in (3) from biphenyl and stearyl chloride. In general, the aromatic dioxo compounds may be prepared by reacting an aromatic hydrocarbon with two mols. of an acyl halide in presence of an inert solvent and a Friedel-Crafts catalyst. Other dioxo compounds mentioned as starting materials are 1,3,5 - trimethyl - 2,4 - diacyl benzenes, 1,3,5 - trimethyl - 4 - ethyl - 2,6 - diacyl benzenes, 1,2,4,5 - tetramethyl - 3,6 - diacyl benzenes and 1,3 - dimethyl - 2,5 - diacyl benzenes, and m,m1-dimethyl and other alkyl substituted-p,p1-diacyl biphenyls.  The 1,4-diamino phenylenes and 4,41 - diamino biphenylenes are formed together with isomers from which they may be separated, e.g. by distillation.  Specifications 461,236, 461,237 and U.S.A. Specification 2,130,948 are referred to. The Specification as open to inspection under Sect. 91 relates to the production of diamines of the above general formula wherein Ar may be any arylene radical.  This subject-matter does not appear in the Specification as accepted.