GB759871A - Chromium containing azomethine dyestuffs - Google Patents

Abstract

Hydroquinone- and naphthohydroquinonemethylene sulphone ether aldehydes are made by treating hydroquinone- or naphthohydroquinone-methylene sulphone ether with chloroform in caustic soda solution. Specifications 465,738, 493,314 and 493,501 are referred to.ALSO:The invention comprises chromium complexes of o, <\>o - dihydroxyazo - methene dyestuffs of formula <FORM:0759871/IV(c)/1> which are free of COOH and SO3H groups and where R is a benzene or naphthalene residue and at least one R contains an alkyl - sulphone group, which may be attached at both ends to R, or a radicle -SO2.CH2O- linked to two adjacent carbon atoms. They are made by condensing appropriate o - hydroxy - carbonyl - and o - hydroxyamino - compounds in the presence of chromium - yielding agents in water or organic solvents. Specified o - hydroxy - carbonyl compounds are 5 - chloro - and - bromo -, 3, 5 - dichloro -, 3 - nitro - 5 - chloro - 2 - hydroxybenzaldehydes, 2 - hydroxy - 1 - naphthaldehyde and its 6 - bromo - derivative, 5 - hydroxy - benzoxythiol - S - dioxide - 4 - aldehyde and 41 - hydroxy - naphtho - (21, 11:4, 5) - oxathiol - S - dioxide - 31 - aldehyde. Specified o - hydroxyamino compounds are 2 - amino - 1 - phenol and its 4 - sulphonamido - and - methylsulphonyl, 4 - nitro - 6 - chloro-, 4, 6 - dinitro and 3, 4, 6 - trichloro - derivatives and 4 - amino - 5 - hydroxybenzoxathiol - S - dioxide. The dyestuffs dye animal fibres. Examples are provided illustrating the preparation of dyestuffs using certain of the above specified components, o - hydroxyamino compounds used additional to those specified being 5 - nitro-3 - amino - 2 - and - 4 - cresols and 2 - amino - 3 - naphthol, and their use in dyeing wool red or brown shades. Specifications 465,738, 493,314 and 493,501 are referred to.