Patent GB-706370-A (GB)
Title: Improvements relating to chrome-containing azo dyestuffs
IPC: C09B45/16
Filed: 1952-01-10
Abstract: 6-Acetylamino - 2 - aminophenol - 4 - methyl - sulphone is prepared by acetylating 6-nitro-2-aminophenol-4-methylsulphone and reducing the product catalytically in solution in dilute caustic soda lye.ALSO:The invention comprises: complex chromium compounds of the general formula I-Cr-II wherein I and II are co-ordinated monoazo dyestuffs, free from carboxylic and sulphonic acid groups, of the formulae <FORM:0706370/IV(c)/1> and <FORM:0706370/IV(c)/2> wherein A and A1 represent aromatic nuclei of the benzene series in which the hydroxy groups are in ortho-position to the azo groups and the substituents X1 and X2 are in para-position to the hydroxy groups and are selected from alkylsulphonyl groups containing 1-5 carbon atoms and -SO2NY1Y2 groups (Y1 and Y2 being hydrogen atoms or alkyl or hydroxyalkyl groups of 1-5 carbon atoms), or one of them may be a nitro group Pz represents the radical of a 1-aryl-3-methyl-5-pyrazolone of the benzene series coupled in 4-position, and Z represents the radical of a 1-acylamino-7-naphthol coupled in 8-position, and wherein the p  benzene rings may contain further substituents, and the manufacture thereof by treating equimolecular mixtures of I and II with agents yielding chromium in such amounts that at least one chromium atom corresponds to two molecules of azo dyestuff.  The products dye synthetic polyamide and polyurethane fibres, leather, silk and especially wool in brown shades, their solubility being if necessary improved for this purpose by the addition of alkali metal phosphates or carbonates or of wetting or dispersing agents.  Suitable chroming agents are normal and complex salts and hydroxides of tervalent chromium, such as chromium acetate or formate or especially alkali metal (e.g. sodium) or ammonium chromosalicylates.  The monoazo dyestuffs I and II may be prepared from the appropriate components, of which the following are specified: diazo components: 2-aminophenol-4-methyl-, -ethyl-, -n-propyl-, -n-butyl- and -n-amyl-sulphones, 2-aminophenol-4-sulphonic acid amide, methylamide, ethylamide, dimethylamide, diethylamide, hydroxyethylamide and di-(hydroxyethyl)-amide, 6-chloro-6 - acetylamino - and 6 - methyl - 2 - aminophenol4 - alkyl sulphones and - 4 - sulphonic acid amides, 4 - nitro - 2 - aminophenol, and 6 - chloro - and 6-methyl-4-nitro-2-aminophenol; coupling components for I: 1-phenyl-3-methyl-5-pyrazolone and its 3\sv-chloro, 4\sv-bromo, 4\sv-methyl, 4\sv-nitro, 2\sv : 5\sv - and 3\sv : 4\sv-dichloro and 4\sv-methoxy derivatives; coupling components for II: 1-acetyl-, propionyl-, methoxyacetyl-, carbomethoxy- and methoxycarbethoxy-amino-7-naphthol.  When the water solubility of the mixed chromium complex compounds is not sufficient it may be improved by the addition of alkali metal phosphates or carbonates or of wetting or dispersing agents.  Examples describe the preparation of mixed chromium complex compounds from various pairs of dyestuffs from certain of the foregoing components, and the dyeing of wool deep brown from a bath containing Glauber salt with the product from the dyestuffs 2-aminophenol-4-methyl sulphone-->1-(3\sv-chlorophenyl)-3-methyl-5-pyrazolone and 2-aminophenol-4-methyl sulphone-->1-carbomethoxyamino-7-naphthol.