Patent GB-636681-A (GB)
Title: Manufacture and use of new monoazo-dyestuffs
IPC: C09B45/16
Filed: 1947-02-20
Abstract: Dyestuffs capable of being chromed are manufactured by treating a dihydroxymonoazo dyestuff, containing a single sulphonic acid group (i.e. SO3H or a salt thereof) and of the general formula R1-N=N-R2 (wherein R1 represents a naphthalene residue containing a hydroxy group in a position adjacent to the azo group and also containing a single sulphonic acid group, and R2 represents either a naphthalene residue containing a hydroxy group in a position adjacent to the azo group or the residue of a 1-phenyl-3-methyl-5-pyrazolone connected to the azo group in the 4-position), with an acylating agent which contains as the sole acylating group a functionally converted carboxyl group and is otherwise free from groups imparting solubility and substituents convertible thereto by hydrolysis. The starting materials may be obtained by coupling the diazo compound of an o-aminonaphthol sulphonic acid, which may contain further substituents (e.g. 1 : 2- or 2 : 1-aminonaphthol-4-sulphonic acid or the 6-nitro derivative of the former), with a naphthol capable of coupling in a position adjacent to the hydroxy group (e.g. 1-naphthol, coupled under such conditions that coupling occurs in the 2-position, e.g. in a medium rendered strongly alkaline with caustic alkali, 5-chloro-, 5 : 8-dichloro- or 4-methoxy-1-naphthol, 2-naphthol, 6- or 7-methoxy-2-naphthol or 2-naphthol-6-sulphonic acid diethylaminde) or with a 1-phenyl-3-methyl-5-pyrazolone (e.g. the 1-phenyl, 1-m-nitrophenyl or 1-o-chlorophenyl compound).  Suitable acylating agents are carboxylic halides or anhydrides, e.g. cinnamic acid chloride, aryloxyacetic acid halides, acetic anhydride, butyryl chloride and especially compounds of the formula X-R3, wherein X represents a functionally converted carboxyl group capable of bringing about acylation and R3 represents a benzene residue free from groups imparting solubility or substituents convertible thereto (e.g. m- or p-nitrobenzoyl chloride or benzoyl chloride or bromide). The treatment with the acylating agent is advantageously effected in the presence of a tertiary organic base (e.g. pyridine), and preferably in the absence of free alkalies, and the quantity and nature of the acylating agent and the reaction conditions may be selected so that only one or both of the hydroxy groups is esterified.  The products dye fibres of animal origin (e.g. silk, leather and especially wool), mixed fabrics (e.g. of wool and regenerated cellulose), animalized cellulose and artificial fibres of casein, superpolyamides or superpolymethanes, preferably by a single bath chroming process, e.g. from a bath containing an alkali chromate and a buffer salt which prevents the bath becoming alkaline at a raised temperature.  Examples describe the use of certain of the components and acylating agents specified above, and the dyeing of wool a bluish-red tint from a bath containing ammonium sulphate, sodium chromate, Glauber salt and the product obtained by the action of benzoyl chloride on the dyestuff 1 : 2-aminonaphthol - 4 - sulphonic acid --> 1 - phenyl - 3-methyl-5-pyrazolone. Specification 606,814 is referred to.  The Specification as open to inspection under Sect. 91 comprises also the treatment of other o : o1 - dihydroxymonoazo dyestuffs, including those in which R1 in the general formula above may be a residue of the benzene series and R2 the residue of any component coupling in a position adjacent to a hydroxy group (e.g. an o-coupling hydroxybenzene or hydroxyquinoline or an acetoacetic arylide) and in which the single sulphonic acid group may be present in the coupling component, and the use of other acylating agents.  Additional starting materials specified, some of which are used in further examples, are : diazo components : 2-aminophenol - 4 - sulphonic acid, 4 - methyl - 2-aminophenol - 5 - sulphonic acid, 4 - chloro-and 4 - nitro - 2 - aminophenol - 6 - sulphonic acid, 5- and 6-nitro-2-aminophenol-4-sulphonic acid, 2 - aminophenol - 4 - sulphonic - 6 - carboxylic acid, 2-aminophenol, 4-chloro-, 4 : 6-dichloro -, 3 : 4 : 6 - trichloro -, 6 - nitro - 4-methyl-, 4-, 5- and 6-nitro-, 5- and 6-nitro-4-chloro-, 4-nitro-6-chloro- and 4 : 6-dinitro-2-aminophenol and 2-aminophenol-4-sulphodiethylamide; coupling components : p-methyl-, p-tert.-amyl- and p-isobutyl-phenol, 5-chloro-8-hydroxyquinoline, 2 : 4-dihydroxyquinoline, acetoacetic anilide and o-anidide, 1 : 4-, 1 : 5-, 2 : 4-, 2 : 5- and 2 : 7-naphtholsulphonic acids, 1 - naphthol - 3 - sulpho - N - methylanilide - 8-sulphonic acid, and 1-(31- and 41-sulpho-, 21-chloro - 51 - sulpho - and 21 - methyl - 51-sulpho - phenyl - 3 - methyl - 5 - pyrazolone; acylating agents: benzene- and toluene-sulpochlorides, maleic anhydride and terephthalic acid chloride.  This subject-matter does not appear in the Specification as accepted.