Patent GB-630452-A (GB)
Title: Manufacture of new polyazo-dyestuffs
IPC: C09B33/12
Filed: 1947-04-08
Abstract: Pyrazolone derivatives of the general formula Py1-R1-Py2, wherein R1 represents a 4 : 41-diphenylene residue (which may contain further substituents, e.g. alkyl or alkoxy groups or halogen atoms), and Py1 and Py2 each represent the residue of a 5-pyrazolone bound in the 1-position to R1 and containing in the 3-position a methyl or carboxyl group, are manufactured by tetrazotizing a 4 : 41-diaminodiphenyl compound (e.g. benzidine itself or its 3 : 31-dichloro-derivative), reducing the product to the corresponding dihydrazine, and condensing this with acetoacetic or oxalacetic ester.  The products are useful as dye intermediates (see Group IV (c)). Specifications 455,274 and 22310/39, (as open to inspection under Sect. 91), are referred to.ALSO:Polyazo dyestuffs free from sulphonic acid groups are manufactured by coupling a compound of the general formula Py1-R1-Py2, wherein R1 represents a 4 : 41-diphenylene residue (which may contain further substituents, e.g. alkyl or alkoxy groups or halogen atoms), and Py1 and Py2 each represent the residue of a pyrazolone bound in the 1-position to the diphenylene residue (which residues are advantageously identical, and may contain in the 3-position a carboxyl group or preferably an alkyl group), with two molecular proportions of the same or different diazo compounds of aromatic amines, at least one of which is of the general formula <FORM:0630452/IV (c)/1> wherein R2 represents a benzene radical (which may contain further substituents, e.g. a nitro group, an alkyl radical, or a halogen atom), X represents a group occupying a position vicinal to the -NH2 group and capable of taking part in the formation of heavy metal complexes (e.g. a carboxyl, hydroxy or methoxy group) and Y represents an acid amide group bound by the acid residue to R2, preferably in p-position to X (e.g. a carboxylic or sulphonic acid amide group in which the nitrogen atom may be free from substituents or may carry one or two substituents, e.g. one or two alkyl radicals, or an aryl radical, or an aryl radical and an alkyl radical, the aryl radical being preferably of the benzene series and optionally carrying further substituents).  Suitable diazo components of this type are 2-amino-1-hydroxy-4-benzanilide and its 6-chloro and 41-sulphodimethylamido derivatives, 2-amino-1-hydroxy-4 - chloro - and 4 - nitro - 6 - benzanilide, 2-aminophenol - 4 - sulphonic acid anilide, N - methylanilide and a  - naphthylamide, 2-amino - 1 - methoxybenzene - 4 - sulphonic acid anilide, 2-amino-1-(carboxymethoxy)-4-benzanilide, and especially 2-aminophenol-4-sulphonamide and its 6-chloro-, 6-nitro- and 6-methyl-derivatives.  The second diazo component, if not of the same type as the first, preferably likewise contains a metal complex forming group in o-position to the diazotizable amino group, and it may contain an azo group.  The coupling may be conducted in an acid, a neutral or advantageously an alkaline medium (e.g. one obtained by dissolving the coupling component with the aid of a small excess of alkali hydroxide and adding further alkali in the form of an alkali carbonate), and, when two different diazo compounds are used, it is advantageous to conduct the first coupling in an acid medium (preferably one rendered acid with acetic acid) and the second in an alkaline medium.  The products dye cellulose fibres (e.g. cotton and artificial silk and staple fibres of regenerated cellulose), and also animal fibres (e.g. wool, silk and leather), and may be converted in substance, in the dyebath or on the fibre into complex metal (e.g. copper, chromium, iron, nickel or cobalt) compounds.  The complex metal (especially cobalt and nickel) compounds produced in substance can be used for colouring masses and solutions thereof, such as nitrocellulose lacquers, artificial resins and spinning masses. Examples describe the coupling of the diazo compounds of certain of the amines specified above with 1 : 11-(diphenylene - 4 : 41) - bis - (3 - methyl - 5 - pyrazolone, the treatment of one of the products with an alkaline solution of complex sodium cobalt tartrate, and the after-coppered dyeing of cotton in a yellow tint with the same product.  Additional coupling components specified are those containing a 3 : 31-dichloro-, 3 : 31-dimethyl- or 3 : 31-dimethoxy-4 : 41-diphenylene residue.  Specifications 455,274 and 22310/39 (as open to inspection under Sect. 91) are referred to.