GB610311A - Improvements in the production of basic polyamides - Google Patents

Abstract

Basic polyamides are prepared by heating a dicarboxylic acid free from other reaction groups with a polyamine containing two primary amino groups and at least one secondary amino group or a mixture of such an amine with a diprimary amine, the primary amino groups and carboxylic groups being substantially equivalent. The reaction may be stopped before the polymer becomes infusible or insoluble and the product used to form filaments or films, or in some cases by continuing the reaction an insoluble polymer may be produced which may be used for absorbing the acid radicle from aqueous liquors containing salts or acids. Preferred polyamines are dihexylenetriamine, 1,2-bis-o -aminohexylaminoethane, or similar polyamines. 4,41-Diaminodiphenylamine is also suitable. Diethylene triamine, triethylene tetramine, tetraethylene pentamine and 1,6-bis-b -aminothylamino hexene are also mentioned. Suitable amines may be prepared by reacting an a o -paraffin dihalide with excess of an a o -diamino-paraffin, by reacting an a o -paraffin dihalide with excess amino-nitrile and reducing the nitrile groups, by reacting an a o -diamino paraffin with excess halogen-nitrile and reducing the nitrile groups, by reacting an a o -diamino paraffin with acrylonitrile or methacrylonitrile followed by reduction or by reacting a o -paraffin dihalide with a mono-acidylated diamine and splitting off the acidyl groups. Suitable acids are oxalic, adipic, pimelic, suberic azelaic, sebacic, diglycollic, thiodiglycollic, N-methyl-imino-diacetic, or N-methyl-imino-dipropionic. The acids may be replaced by their equivalents, i.e. alkyl or aryl esters, amides or nitriles (with water). Amino groups may be replaced by acidylamino, e.g. formylamino, arylurethane, isocyano, or isothiocyano groups. The products especially as filaments may be after-treated with aldehydes, acylating or alkylating agents, e.g. formaldehyde, acid chlorides including sulphuryl chloride, carbon disulphide, a di-isocyanate, acrylonitrile or an acrylic ester. In examples (1) and (2), 1,2-bis-(o -aminohexylamino)-ethane, prepared from ethylene dibromide and excess hexamethylene diamine, is condensed with adipic acid, suberic or sebacic acids. The product gave a nitroso derivative with nitrous acid in dilute sulphuric acid. (3) The same polyamine is condensed with ethyl oxalate. (4) Dihexylene triamine was condensed with ethyl oxalate. (5) Dihexylene triamine was condensed with suberic acid. (6) A mixed polymer was prepared from hexamethylenediamine, ethyl oxalate and 1,2-bis-(o -aminohexylamino)-ethane. (7) Undrawn fibres obtained from the polymer of example (3) were after-treated with (a) ethyl oxalate, (b) carbon disulphide, and (c) ethyl carbonate. (8) Films cast from a methanol solution of the adipic acid polymer of example (2) were treated with maleic acid in acetone. Generally the polymers according to the invention were soluble or swollen in m-cresol or formic acid. Polymer-forming reactions are generally carried out at 100-300 DEG C. The initial stages may be at lower temperatures and may be under reflux. Diluents, e.g. phenol, cresols, or xylenols may be present in the reaction mixture. Vacuum or a current of inert gas may aid removal of volatile reaction products. A condensation catalyst, e.g. .01-.1 per cent of phosphoric acid may be employed. Air should be excluded. Filaments may be spun by dry or wet methods, plasticisers being added if desired. Specification 597,253 is referred to.ALSO:Amines suitable for the production of basic polyamides (see Group IV (a)) may be prepared by reacting an a ,o -paraffin dihalide with excess of an a ,o -diamino-paraffin, by reacting an a ,o -paraffin dihalide with excess amino-nitrile and reducing the nitrile groups, by reacting an a ,o -diamino paraffin with excess halogen-nitrile and reducing the nitrile groups, by reacting an a ,o -diamino paraffin with acrylonitrile or methacrylonitrile followed by reduction or by reacting a ,o -paraffin dihalide with a mono-acidylated diamine and splitting off the acidyl groups. In examples (1) and (2), 1,2-bis-(o -aminohexylamino) ethane is prepared from ethylene dibromide and excess hexamethylene diamine. Specification 597,253 is referred to.