Patent GB-703133-A (GB)
Title: Process for the preparation of polyazo dyestuffs
IPC: C09B33/18
Filed: 1952-02-13
Abstract: The invention comprises: polyazo dyestuffs containing at least two sulphonic acid groups and of the general formula <FORM:0703133/IV(c)/1> wherein the azo residues are attached to the naphthalene nucleus in the 1- and 6-positions, R represents the residue of a diazo component of the benzene series containing a metal complex forming substituent in ortho-position to the azo group, A and B represent residues of the benzene or naphthalene series, the azo groups in B being in paraposition to each other, and the nucleus I may be further substituted by methyl, methoxy or acylamino groups, and their copper complex compounds; the manufacture thereof by coupling a diazo compound corresponding to one of the azo residues indicated with a 2 : 5-dihydroxynaphthalene-7-sulphonic acid containing the other of the azo residues indicated in the 1- or 6-position, or with a copper complex compound thereof, advantageously in the presence of organic bases such as pyridine and quinoline, and, if desired, treating the product, in substance or on the fibre, with agents yielding copper; and the dyeing of cotton and regenerated cellulose fibres (in grey tints) with the products.  The coppering in substance is advantageously effected in such a manner that the methoxy groups are split, e.g. by heating with copper salts, if necessary under pressure, in weakly acid to alkaline media, in the presence or absence of ammonia or organic bases, or in the melt of alkali metal salts of low molecular aliphatic carboxylic acids.  The coupling components for the main step of the process indicated above are obtainable by coupling the appropriate diazo or diazo-disazo compound with 2 : 5-dihydroxynaphthalene-7-sulphonic acid, or with 2-amino-5-naphthol-7-sulphonic acid followed by replacement of the amino group by a hydroxy group.  The aminodisazo dyestuffs of the general formula <FORM:0703133/IV(c)/2> employed as diazo components are obtainable by diazotizing a starting component A-NH2, coupling in a weakly acid medium with a middle component H-B-NH2, rediazotizing and coupling in a weakly acid medium with a 1-methoxy-2-aminobenzene which may be further substituted by one or more methyl, methoxy or acylamino groups, or by diazotizing, for example, 1-amino-4-nitrobenzene-2-sulphonic acid, coupling in an alkaline medium with an o-hydroxycarboxylic acid of the benzene or naphthalene series, reducing the nitro group with sodium sulphide, diazotizing the resulting amino group and finally coupling as before.  In the first process, the monoazo dyestuff A-NH2-->H-B-NH2 may be replaced by, for example, 4-amino-1 : 1\sv-azobenzene or its 4\sv-sulphonic acid or 3 : 4\sv-disulphonic acid.  In examples: (1) the copper complex of the dyestuff obtained by coupling diazotized anthranilic acid in an acid medium with 2-amino-5-naphthol-7-sulphonic acid and replacing the amino group by a hydroxy group is coupled in aqueous ammonia in the presence of pyridine with the diazo compound of the aminodisazo dyestuff 2-hydroxy-5-aminobenzene-1-carboxylic acid-->1-aminonaphthalene-7-sulphonic acid-->2-amino-1-methoxy-4-methylbenzene; the product may be further coppered by heating with ammoniacal copper sulphate solution; the final product may also be produced by coupling the diazo compound of the aminodisazo dyestuff with 2 : 5-dihydroxynaphthalene-7-sulphonic acid in the presence of sodium bicarbonate, coupling the product with diazotized anthranilic acid in the presence of pyridine and coppering as before; (2) the anthranilic acid in the first part of (1) is replaced by 2-amino-1-carboxy-benzene-4-sulphonic acid and the aminodisazo dyestuff by 2-hydroxy-1-carboxy-5-aminobenzene-3-sulphonic acid-->m - toluidine-->2 - amino - 1 - methoxy-4-methylbenzene; the product may be further coppered by heating with aqueous copper sulphate solution; (3) the anthranilic acid in the first part of (1) is replaced by 2-amino-5-nitrobenzoic acid and the aminodisazo dyestuff by 2-aminonaphthalene-4 : 8-disulphonic acid --> m - toluidine --> 2 - amino - 1 : 4 - dimethoxybenzene; further copering may be effected as in (1); (4) the dyestuff anthranilic acid-->2 : 5-dihydroxynaphthalene-7-sulphonic acid is coupled as in (1) with the diazo compound of the aminodisazo dyestuff 1-aminobenzene-2 : 5-disulphonic acid --> a -naphthylamine-->2-amino-1-methoxy-4-methylbenzene, and the product is coppered as in (2); (5) the trisazo dyestuff 1-aminonaphthalene-4-sulphonic acid-->1-aminonaphthalene-7-sulphonic acid-->1-methoxy 2-amino-4-acetylaminobenzene --> 2 : 5-dihydroxynaphthalene-7-sulphonic acid is coupled in aqueous ammonia in the presence of pyridine with diazotized 1-methoxy-2-aminobenzene-4-sulphonic acid, and the product is coppered as in (2); (6) the aminodisazo dyestuff in the first part of (1) is replaced by 4-aminoazobenzene-3 : 41-disulphonic acid--> 1 : 4-dimethoxy-2-aminobenzene and further coppering is effected as in (1); (7) the anthranilic acid in the first part of (1) is replaced by 2-amino-5-chlorobenzoic acid and the aminodisazo dyestuff by salicylic acid\sM1-amino-4-nitrobenzene-2-sulphonic acid (reduced)-->1-methoxy-2-amino-4-methylbenzene, the product being further coppered as in (1); (8) the aminodisazo dyestuff in (2) is replaced by a -naphthylamine --> 1 - aminonaphthalene - 7 - sulphonic acid --> 1 - methoxy - 2 - amino - 4 - methylbenzene; (9) cotton is dyed greenish grey with the product of (3) from a bath containing Glauber salt.  Lists of additional components are given.