Verfahren zur Herstellung von chromhaltigen Azofarbstoffen

The invention comprises complex chromium compounds containing one atomic proportion of chromium bound to two complex formers of which one is a monoazo dyestuff containing one or more sulphonic acid groups but free from carboxylic acid groups and the other is an 8-hydroxyquinoline. The dyes are prepared by (a) reacting an appropriate 1 : 1-chromium complex of a monoazo dye with an 8-hydroxyquinoline; (b) chroming an o:o1-dihydroxy- or o-hydroxy-o1-amino-mono-azo dye in the presence of an 8-hydroxyquinoline or (c) reacting a chromium complex containing per atom of chromium one molecule of an appropriate monoazo dye and one molecule of a colourless complex former with an 8-hydroxyquinoline. Specified substituted 8-hydroxy-quinolines are the 5-chloro-, 5- or 7-sulpho-, 6-hydroxy-, 5,7-dibromo- or -diiodo- and 5-chloro-7-sulphocompounds. The dyes may be used to colour wool, silk, leather and synthetic polyamides and polyurethanes. In examples: (1) the 1 : 1-chromium complex of 1-(21-hydroxy-41-nitrophenyl-azo) - 2 - naphthylamine - 6 - sulphonic acid is reacted with 8-hydroxyquinoline in aqueous sodium hydroxide solution; (2) 1-(21-hydroxy - 41 - nitrophenylazo) - 2 - naphthylamine - 6 - sulphonic acid, 8 - hydroxyquinoline, chromic formate and sodium bicarbonate are heated in formamide to give the same product as in (1). Further examples are specified.