295,594. Soc. of Chemical Industry in Basle. Aug. 13, 1927, [Convention date]. Azo dyes, soluble chromium compounds of.- Azo dyestuffs are converted into chromium compounds by treatment, in presence of a watersoluble sulphide, with hydrated chromium oxide with or without pressure, a protective colloid or an organic or inorganic salt being added if necessary. In some cases the presence of organic agents such as glucose, soluble degradation products of starch or cellulose, glycerine, sulphitecellulose lye, or lignin-sulphonic acid favours the reaction. When the parent dyestuffs contain nitro groups the products may contain amino, azo, or azoxy groups according to the proportion of reducing agent used. The products give fast dyeings on vegetable, animal, or regenerated cellulose fibres and are suitable for colouring varnishes. The following examples are specified. (1) A paste containing the dyestuff 6-nitro-2- aminophenol-4-sulphonic ->- #-naphthol is. heated for 12-15 hrs. at 90-100‹ C. with sodium sulphide, chromium hydroxide paste, and sulphite cellulose lye; the separated dyestuff dyes wool from a sulphuric acid bath a. fast brownviolet. (2) The same dyestuff paste is heated for 15 hrs. at 90-100‹ C. with sodium sulphide, chromium hydroxide paste and caustic soda lye; the separated dyestuff dyes wool from a sulphuricacid bath a fast brown-violet, and may be diazotized and coupled with #-naphthol to produce a disazo dyestuff which dyes silk from an acetic acid bath a fast black-blue. (3) A paste containing the sodium salt of the dyestuff 4-chloro-2- aminophenol # 1-(m-sulphamido) phenyl-3- methyl-5-pyrazolone is heated for 6 hrs. under pressure with sodium sulphide, chromium hydroxide paste, and water; the separated dyestuff dyes wool from a sulphuric acid bath a fast red-orange; the corresponding chromium compounds of the dyestuffs 1 : 2-aminonaphthol-4- sulphoxiic acid # 1-phenyl-3-methyl-5-pyrazolone or 1-(m-nitro)-phenyl-3-methyl-5-pyrazolone dye wool fast red tints, and that of a dyestuff chloraminophenolsulphonic acid # 1-phenyl-3- methyl-5-pyrazolone dyes wool fast orange-red. (4) The dyestuff 4-chloro-2-aminophenol # barbituric acid is heated for 8 hrs. at 80-90‹ C. with sodium sulphide, chromium hydroxide paste, caustic soda. lye, sugar, and water; the separated dyestuff dyes wool a fast orange; if the heating is for 4 hrs. at 110-115‹ C. the product dyes a brown-orange. (5) The sodium, salt of the dyestuff 4-nitro-2-aminophenol # #-napbthol is heated for 16 hrs. at 90-100‹ C. with sodium sulphide, chromium hydroxide paste. caustic soda lye, and water: the product, treated with formalehyde and bisulphite, dyes silk and wool fast violet-black. (6) The sodium salt of the dyestuff from the nitrated diazo compound of 1 : 2-aminonaphthol-4-sulphonic acid and 1 : 4-naphtholsulphonic acid is heated for 3 hrs. at 90-100‹ C. with sodium sulphide, chromium hydroxide paste, sugar, and water; the product dyes wool and silk fast blue-grey. (7) The sodium salt of the dyestuff 1 : 2-aminonaphthol-4- sulphonic acid # 1-naphthol-4- : 8-disulphonic acid is heated for 12 hours at 90-100‹ C. with sodium sulphide, chromium hydroxide paste, and water; the product dyes wool a fast blue.-grey. (8) The sodium salt of the dyestuff 2 : 1-aminonaphthol-4 : 8-disulphonic acid # barbituric acid is heated for 16-20 hrs. at 90-100‹ C. with sodium sulphide, chromium hydroxide paste, caustic potash, glycerine, and water; the product dyes wool a fast. bluish red. (9) The disodium salt of the dyestuff 5-nitro-2-aminophenol -> phenyl- 2 : 5: 7-acid is heated for 16 hrs. at 90-100‹ C. with sodium sulphide, chromium hydroxide paste, and glycol; the product dyes cotton a bluegrey. (10) A paste containing the dyestuff from the nitrated diazo compounds of 1 : 2-aminonaphthol-4-sulphonic acid and #-naphthol is heated for 12 hrs. at 80-85‹ C. with sodium sulphide, chromium hydroxide paste, and caustic potash; the product dyes wool and silk fast blue-grey. (11) and (12). Wool and silk are, dyed in acid baths containing the. lyestuffs of examles (3) and (6) respectively. (13) Cotton is dyed in a Glauber's salt bath containing the dyestuff of example (9). (14). 2 per cent of the dyestuff of example (3) is incorporated in a hot celluloid varnish. (15) Artificial silk, e.g. viscose, is dyed in a bath containing salt, which is neutral, feebly alkaline, or feebly acid with acetic acid.