Patent GB-709401-A (GB)
Title: Manufacture of metalliferous azo-dyestuffs
Inventor: BUEHLER ARTHUR
IPC: C09B45/14
Filed: 1951-10-12
Abstract: The invention comprises cobaltiferous and chromiferous azo dyes containing two monoazo dyestuffs bound in complex union, the ratio of metal atoms to dyestuff molecules being less than 1 : 1 (and preferably about 1 : 2); the monoazo dyestuffs are free from sulphonic acid and carboxylic acid groups and are of the formula <FORM:0709401/IV(c)/1> where R2 is alkyl of 4 or more carbon atoms and R is a benzene residue attached oto the hydroxyl group; in one at least of the dyestuffs the residue R is substituted by -SO2NH2, -SO2CH3 or -SO2C2H5.  The two dyestuffs may be the same or different. The metalliferous dyestuffs may be made by (1) metallizing the monoazo dyestuffs or mixtures thereof with 1/2 to 1 atom of metal per dyestuff molecule and/or carrying out the process in weakly acid or alkaline medium; or (2) making a 1 : 1 metal complex of one of the dyestuffs by normal methods and treating it with a further mol of the same or a different metal-free dyestuff.  Suitable metallizing agents for method (1) are cobalt acetate, cobalt sulphate, and complex chromium compounds of hydroxy-acids such as lactic, glycollic, citric, tartaric, salicylic or cresotinic.  There may be present bases, salts of organic acids or organic solvents.  For method (2) there can be used cobalt or chromium salts such as the fluoride or sulphate.  The metal-free starting materials may be obtained as in Specifications 695,512, [Group IV(b)], and 697,056 and need not be separated from the coupling mixture before metallization.  The products of the invention can be used for dyeing and printing silk, leather, wool and superpolyamides or superpolyurethanes, from neutral or weakly acid solutions.  The dyebath may contain assistants such as polyglycol ethers.  Examples show (1) chroming 2 mols of the dyestuff 2-aminophenol-5-sulphonamide --> 1-n-butyl-3-methyl-5-pyrazolone; (2) preparation and chroming of the dyestuff 2-aminophenol-4-sulphonamide (or its 6-nitro derivative) --> 1-n-octyl-3-methyl-5-pyrazolone; (3) preparation of the dyestuff 5-nitro-2-aminophenol --> 1-n-butyl-3-methyl-5-pyrazolone, and chroming a mixture of this and the dyestuff of (1); (4) preparation and chroming of the dyestuff 2-aminophenol-4-methylsulphone --> 1-n-butyl-3-methyl-5-pyrazolone; (5) chroming a mixture of the dyestuffs 2-aminophenol-4-sulphonamide --> 1-n-butyl-3-methyl-5-pyrazolone and 6-nitro-2-aminophenol-4-sulphonamide --> 1-n-octyl-3-methyl-5-pyrazolone; (6) preparation of cobalt analogues of (1), (2) and (4); (7) cobalting a mixture of the dyestuffs 2-aminophenol-4-sulphonamide --> 1-n-butyl-3-methyl-5-pyrazolone and 5-nitro-2-aminophenol --> 1-n-butyl-3-methyl-5-pyrazolone; (8) preparation, chroming and cobalting of the dyestuff 2-aminophenol-4-sulphonamide --> 1-n-hexyl-3-methyl-5-pyrazolone; (9) as (8) using 1-n-amyl-3-methyl-5-pyrazolone; (10) chroming and cobalting the dyestuff 2-aminophenol-5-sulphonamide --> 1-n-amyl-3-methyl-5-pyrazolone; (11) dyeing wool from an acetic acid bath with the product of (1) or the cobalt analogue of (2). Other suitable components are mentioned.