GB276372A - Manufacture of arylazo-diarylamines - Google Patents

Abstract

276,372. I. G. Farbenindustrie Akt.- Ges. Aug. 21, 1926, [Convention date]. Samples furnished. Azo dyes.-Arylazodiarylamines are obtained by causing a monoaminoazo dye to react with an aromatic nitro compound of the benzene series containing at least one exchangeable halogen atom and at least one sulpho or carboxyl group. The aminoazo dyes used as parent materials may be of the benzene or naphthalene series, or may contain both a benzene and a naphthalene nucleus in either of which the amino group may be present; other substituents capable of increasing the solubility, e.g. sulpho or carboxyl groups may also be present. The halogenated and sulphonated or carboxylated nitro compounds used may contain more than one nitro, sulpho, or carboxyl group; both sulpho and carboxyl groups may be present if desired. The products are soluble in water and dye animal fibres; those containing not more than one sulpho group are also suitable for dyeing cellulose esters or ethers. The condensation is preferably effected by boiling in the presence of an acid-binding agent, e.g. sodium acetate or chalk; in cases where the halogen is exchanged with difficulty, e.g. with the mononitrohalogen benzene sulphonic or carboxylic acids, the reaction may be conducted under pressure, preferably a pressure of 6-12 atmospheres. In examples, (1) p-aminoazobenzene is condensed with potassium 1-chlor-2 : 6-dinitrobenzene-4-sulphonate; the product dyes acetyl cellulose yellow; (2) aminoazobenzene is condensed with 1- chlor-2-nitrobenzene-4-sulphonic acid under pressure ; the product dyes animal fibres and acetate silk yellow. Similar products are obtained from the nitrohalogenbenzene carboxylic acids; that from aminoazobenzene and 1-chlor-2: 4-dinitrobenzene-6-carboxylic acid dyes wool reddish-yellow and acetate silk an intense golden-yellow. The Specification as open to inspection under Sect. 91 (3) (a) states that nitro compounds of the naphthalene series may be used, and comprises also an example in which p-aminoazobenzene sulphonic acid is condensed with potassium 1-chlor-2 : 6-dinitrobenzene-4-sulphonate; the product dyes wool intense yellow shades. This subject-matter does not appear in the Specification as accepted.