Patent GB-589145-A (GB)
Title: Manufacture of monoazo-dyestuffs
Filed: 1944-11-22
Abstract: Monoazo dyes are manufactured by diazotizing an amine of the general formula <FORM:0589145/IV/1> in which X represents an -SO3H or -SO2- aryl group, and Y a mono- or poly-nuclear residue of the benzene series comprising an o-hydroxycarboxyphenyl residue, and in which the benzene ring having the substituent X may contain further substituents, and coupling the resulting diazo compound in an acid medium with 2 : 8 : 6-aminonaphtholsulphonic acid or an N-monoalkyl (e.g. the N-monomethyl) derivative thereof.  The products dye wool from an acid bath bright red shades which are only slightly changed by after-chroming.  In an example 2 : 8 : 6-acid is coupled with diazotized 3 - (31 - amino - 41 - sulphobenzoyl)-amino - 2 - hydroxybenzoic acid, 5 - (31 - amino-41 - sulphobenzoyl) - amino - 2 - hydroxybenzoic acid or its 3-methyl-derivative, 5-(61-chloro-31-amino - 41 - sulphobenzoyl) - amino - 2 - hydroxybenzoic acid, 41 - (311 - amino - 411 - sulphobenzoyl) - amino - 3 - methyl - 4 - hydroxydiphenylmethane - 5 - carboxylic acid, 311-(3111-amino - 4111 - sulphobenzoyl) - amino - 2 : 21 - dihydroxy - 5 : 51 - dimethyltriphenylmethane - 3 : 31 - dicarboxylic acid or 5-[31 - amino - 41 - (p - tolylsulphone) - benzoyl] - amino - 2 - hydroxybenzoic acid.  Specification 10168/13, [Class 2 (iii)], is referred to.  Amines of the general formula given above are obtainable by condensing an o-hydroxycarboxy compound of the benzene series, containing an amino group, with a 4-halogen-3-nitrobenzoyl halide in the presence of an acid-binding agent, exchanging the halogen atom for a sulphonic acid group by the means of sodium sulphite, or for an aryl-sulphone residue by means of a salt of an arylsulphinic acid, and reducing the nitro group. o-Hydroxycarboxy compounds specified are 3- and 5-amino-, 3 - amino - 5 - methyl-, 5 - amino - 3- and -4-methyl-, 3-amino-5-sulpho- and 5-amino-3-sulpho-2-hydroxybenzoic acids, 41-amino-3-methyl - 4 - hydroxydiphenylmethane - 5 - carboxylic acid and 311-amino-2 : 21-dihydroxy-5 : 51-dimethyltriphenylmethane-3 : 31-dicarboxylic acid.  41 - Amino - 3 - methyl - 4 - hydroxydiphenylmethane - 5 - carboxylic acid is obtainable by heating 5-chloromethyl-3-methyl-2-hydroxybenzoic acid with aniline in water for several hours.  311 - Amino - 2 : 21 - dihydroxy - 5 : 51 - dimethyltriphenylmethane-3 : 31-dicarboxylic acid is obtainable by condensing one molecular proportion of m-nitrobenzaldehyde with two of p-cresotic acid and reducing the nitro group.  The Specification as open to inspection under Sect. 91 comprises also the use of diazo components of the general formula above in which X represents halogen, which compounds are obtainable as described above except that the step of exchanging the halogen atom for a sulphonic acid or arylsulphone group is omitted.  In an additional example, N-methyl-2 : 8 : 6-acid is coupled with diazotized 5-(41-chloro-31-aminobenzoyl) - amino - 2 - hydroxybenzoic acid or its 3-sulpho-derivative, 3-(41-chloro-31-aminobenzoyl) - amino - 5 - methyl - 2 - hydroxybenzoic acid or 5-(21 : 41-dichloro-31-aminobenzoyl) - amino - 2 - hydroxybenzoic acid.  This subject-matter does not appear in the Specification as accepted.