GB741638A - Improvements relating to chromium containing monoazo dyestuffs and their use - Google Patents

Abstract

The invention comprises chromium compounds of the formula [D-Cr-D]M2 where M2 is an alkali metal or ammonium cation and D is a dyestuff which has no water solubilising groups which dissociate acid in neutral water of formula <FORM:0741638/IV(c)/1> where R is an unsubstituted or substituted alkyl group having a total of at most 4 C atoms, X is hydrogen or halogen, Y1 is H or an alkyl, cycloalkyl or phenyl group and Y2 is H or an alkyl group and Y1 and Y2 may be found together in the form of a ring by themselves or with oxygen. They may be made by treating dyestuffs of the above formula in which the hydrogen group of the benzene ring is replaced by OR1 where R1 is as R with chromium-yielding agents so that there is 1 chromium atom to two dyestuff molecules and under conditions to remove R1. Preferably R and R1 are hydroxyl substituted alkyl groups which may be etherized. The unmetallized dyestuffs may be made by coupling the diazotised 2, 5-dialkoxy amine with the appropriate naphthol advantageously in an alkaline medium. Specified amines from which the sulphonamides may be derived are methyl-, ethyl-, propyl-, butyl, cyclohexyl-, dimethyl- and diethyl-amines, aniline, toluidines, xylidines, anisdines, phenetidines, piperidine, morpholine and monomethyl and -ethyl-aniline. Chroming may be effected with chromic sulphate, formate and acetate and alkali metal and ammonium salts of chromosalicylic acid, advantageously at over 100 DEG C in aqueous solution or suspension under pressure preferably in the presence of a wetting or dispersing agent such as turkey red oil at 120-150 DEG C. Chroming may also be effected in alcohol under pressure or in solvents such as ethylene glycol, ethylene glycol monomethyl- or monoethyl-ether, formamide, acetamide or in a urea melt at 135-155 DEG C. The dyestuffs dye wool and synthetic polypeptide fibres from a neutral to weakly acid bath in blue shades. In Examples (1) diazotised 1-amino-, 5-dimethoxy benzene or its 4-chloro-derivative are coupled with 1-hydroxynaphthalene-3-sulphonic acid dimethylamide and the resulting dyestuff chromed; (2) diazotised 1-amino-2, 5-dimethoxy benzene is coupled with 1 - hydroxynaphthalene-3-sulphonic acid piperidide and the resulting dyestuff chromed. In a Table showing chromed dyestuffs preparable as in the Examples the following values are given for R and R1, methyl, ethyl and hydroxyethel, for X, H and C1, for Y2, H, methyl and ethyl, for Y1, H, methyl, ethyl, phenyl, cyclohexyl and Y1 and Y2 combined as a morpholine residue.