GB709495A - Manufacture of new monoazo-dyestuffs - Google Patents

Abstract

The invention comprises: monoazo dyestuffs of the general formula <FORM:0709495/IV(c)/1> (wherein X represents a sulphonic acid amide group and R the residue of a coupling component free from sulphonic and carboxylic acid groups and bound to the azo linkage in a position vicinal to a hydroxy group); the manufacture thereof by coupling a diazotized 4-nitro-2-aminophenol-6-sulphonic acid amide with a coupling component corresponding to the residue R; and a process for dyeing or printing therewith. As diazo components may be employed heterocyclic amides, cycloalkyl or aralkyl amides of 4-nitro-2-aminophenol-4-sulphonic acid, or especially compounds containing a group -SO2 NHCn-1 H2n-1 where n=1-7. Suitable coupling components are ortho-coupling phenols p and naphthols, especially 1-acylamino-7-naphthols coupling in the 8-position, and enolized or enolizable keto-methylene compounds such as acylacetic amides (e.g. arylides), 5-pyrazolones coupling in the 4-position, 2:4-dioxyquinoline and barbituric acid. The products may be treated with an agent yielding metal (e.g. chromium) in substance, in the dyebath or on the fibre (e.g. on wool by the after-chroming or the single-bath chroming process). Examples describe the preparation of the following dyestuffs: (1) 4 - nitro - 2 - aminophenol - 6 - sulphonic acid amide --> 1 - phenyl - 3 - methyl - 5-pyrazolone or b -naphthol; (2) the diazo component of (1) or the corresponding methylamide --> p-cresol. A table gives the properties of the following additional dyestuffs: 4-nitro-2-aminophenol-6-sulphonic acid amide --> 4-methyl-2-acetylaminophenol, 4-acetylaminophenol, 1-acetylamino- or 1-benzoylamino-7-naphthol, 2:4-dioxyquinoline or 4-tert.-amylphenol; 4-nitro-2-aminophenol-6-sulphonic acid methylamide --> 1-benzoylamino- or 1-n-butyrylamino-7-naphthol; 4-nitro-2-aminophenol-6-sulphonic acid anilide-->3-methyl-5-pyrazolone. A list of still further components is given. In further examples: (3) wool is dyed with the first dyestuff of (1) from a bath containing acetic acid, sodium sulphate and, in the later stages, sulphuric acid, and then treated in the same bath with potassium dichromate, yielding a yellowish orange dyeing; (4) a similar dyeing is obtained by applying the same dyestuff from a bath containing sodium sulphate, potassium chromate, ammonium sulphate and, in the later stages, acetic acid. Specifications 430,926 and 709,493, [Group IV(b)], are referred to.