Patent GB-654744-A (GB)
Title: Manufacture of new trisazo-dyestuffs
IPC: C09B33/22
Filed: 1948-10-05
Abstract: Trisazo dyestuffs are manufactured by coupling a diazo compound of an amine of the general formula R1-N=N-R2-NH2 (wherein R1 represents a benzene residue free from sulphonic acid groups but containing a hydroxy and a carboxyl group in o-position to one another, and R2 represents a 1 : 4-phenylene residue free from sulphonic acid groups but containing an alkoxy group of 1-3 carbon atoms in o-position to the diazotizable amino group) in an alkaline medium (advantageously a medium rendered alkaline with an alkali carbonate, if desired with the addition of an agent favouring coupling or binding acid, e.g. pyridine or an ethanolamine) with a monoazo dyestuff of the general formula <FORM:0654744/IV (c)/1> (wherein R3 represents a benzene residue free from sulphonic acid groups but containing a carboxyl, carboxymethoxy or carboxyethoxy group in o-position to the azo linkage and also containing a nitro group).  Suitable diazo compounds are the products obtained by coupling a diazotized aminophenol - o - carboxylic acid (which may contain further substituents such as halogen atoms or alkyl, alkoxy, nitro or sulphonamide groups, e.g. 6-amino-4-nitro-phenol-2-carboxylic acid, or 4-aminophenol-2-carboxylic acid or its 6-methyl-, 6-chloro- or 6 - nitro - derivative) with a 2-alkoxyaniline capable of coupling in the 4-position (which may be further substituted, especially in the 5-position with a substituent which favours coupling such as an alkyl or alkoxy group, e.g. 2-methoxy-5-methyl-, 2 : 5-dimethoxy-, 2 : 5-diethoxy- or 2-propyloxy-5-methoxy-aniline, or which in the absence of such 5-substituents, as in the case of o-anisidine or o-phenetidine, is preferably in the form of its o -methane sulphonic acid), or those obtained by coupling a diazotized 3-alkoxyaniline containing in the 4-position a group convertible to an amino group (e.g. a nitro or acylamino group) with a hydroxybenzene-o-carboxylic acid capable of coupling, and then converting the 4-substituent to an amino group (e.g. 4-amino-3-methoxy-41-hydroxy - 51 - methyl - 1 : 11 - azobenzene - 31 - carboxylic acid).  Suitable coupling components are obtainable by coupling 2 : 5 : 7-aminonaphtholsulphonic acid in acid (preferably mineral acid) medium with a diazotized non-sulphonated 1-aminobenzene containing p  in the 2-position a carboxy or carboxyalkoxy group and also containing (preferably in the 4-position) a nitro group (e.g. 1-amino-2-carboxy-methoxy-4-nitro-5-methylbenzene or 4-nitroaniline-2-carboxylic acid).  The products dye animal fibres such as wool, silk or leather, and especially cellulosic materials such as cotton, linen, or artificial silk or staple fibres of regenerated cellulose, and may be converted in substance, in the dyebath or on the fibre (e.g. by the process of Specifications 455,274 or 619,969), into complex metal (e.g. copper, chromium, iron, nickel or cobalt) compounds.  Example (1) illustrates the use of certain of the components specified above. In example (2), cotton is dyed navy blue with the dyestuff 4 - aminophenol - 2 - carboxylic acid --> 2 - methoxy - 5 - methylaniline --> 2 : 5 : 7 - acid \sM 4-nitroaniline-2-carboxylic acid from a bath containing sodium carbonate and sulphate, the dyeing being after-treated in one of the following ways: (a) rinsed and then warmed in a bath containing copper sulphate and acetic acid; (b) heated in the dye bath with complex copper-sodium tartrate, rinsed and soaped; or (c) rinsed and treated in a bath containing cupritetramine acetate and the water-soluble condensation product of dicyandiamide and formaldehyde. The Specification as open to inspection under Sect. 91 comprises also the use of diazo components of the first general formula above in which the residue R2 contains in the o-position to the amino group a carboxymethoxy or carboxyethoxy group instead of an alkoxy group, e.g. the dyestuffs 4-aminophenol-2-carboxylic acid --> 5-methyl- or 5-methoxy-2-carboxymethoxyaniline.  This subject-matter does not appear in the Specification as accepted.