GB731199A - Dis- and polyazo dyes and process for their preparation - Google Patents

Abstract

The invention comprises water-soluble disazo and polyazo dyestuffs of the type Pyrene-N : N-benzene-w-NH-CO-CA =CA-CO-NH-(arylazo residue) where one A is hydrogen, chlorine, bromine or methyl, the other A is hydrogen and w is a direct linkage on a radical <FORM:0731199/IV (c)/1> or <FORM:0731199/IV (c)/2> ; those in which the arylazo residue on the right-hand side of the formula is derived from <FORM:0731199/IV (c)/3> are, however, excluded. Preferred products are the symmetrical or unsymmetrical dyestuffs of the type Pyrene-N : N-benzene-w-NH-OC-CH= CH-CO-NH-w-benzene-N : N-pyrene and unsymmetrical dyestuffs of the type Pyrene-N : N-benzene-w-NH-OC-CH= CH-CO-NH-w-R-N= N-R(-N=N-R)n where each R is a benzene or naphthalene residue and n is 0 or 1; the aromatic nuclei may be substituted by alkyl, alkoxy or acylamino (or halogen or nitro in the case of the residues R) and when w is a benzoylamino residue this also may be substituted by halogen, alkyl or alkoxy. All the dyestuffs p contain sufficient solubilizing groups, such as carboxylic acid and sulphonic acid, to make them water-soluble. They are made by condensing dicarboxylic halides of the formula Z-CO-CA=CH-CO-Z(Z=chlorine or bromine) with 2 mols. of the appropriate aminoazo compound or compounds in aqueous solution in the presence of an acid-binding agent, and, if desired, an organic solvent. The products dye cotton and regenerated cellulose yellow, orange or brown shades, fast to light and to crease-resistant finishes and usually dischargeable. In the examples the following are condensed with fumaric dichloride: (1) 2 mols. of 3-aminopyrenedisulphonic acid --> m-toluidine; (2) 1 mol. of 3-aminopyrenedisulphonic acid --> p-xylidine and 1 mol. of 3-aminopyrenedisulphonic acid --> cresidine; (3) 2 mols. of the product obtained by condensing p-nitrobenzoyl chloride with the dyestuff 3 - aminopyrenedisulphonic acid --> m-toluidine and reducing the nitro group; (4) 1 mol. of the product obtained by condensing m-nitrobenzoyl chloride with the dyestuff 3-aminopyrenedisulphonic acid --> p-xylidine and reducing the nitro group, and 1 mol. of the dyestuff 3 - aminopyrenedisulphonic acid --> cresidine; (5) 1 mol. of 3-aminopyrenedisulphonic acid --> m-toluidine and 1 mol. of 2 - naphthylamine - 4 : 8 - disulphonic acid --> cresidine; (6) 1 mol. of 3-aminopyrenedisulphonic acid --> p-xylidine and 1 mol. of sulphanilic acid --> orthanilic acid--> m-toluidine. A table is given of other pairs of dyestuffs that may be condensed with the dicarboxylic halides and other suitable components are mentioned. A further example shows the dyeing of cotton with the product of (2) above.