GB459949A - Process for the manufacture of o-hydroxyazo dyestuffs - Google Patents

Abstract

o-Hydroxyazo dyestuffs are manufactured by coupling o-hydroxydiazo compounds, e.g. of the benzene and naphthalene series, in alkaline medium with derivatives of 2-amino-7-naphthol in which one hydrogen atom of the amino group is substituted by a hydrocarbon radicle or a substituted hydrocarbon radicle, e.g. alkyl, hydroxyalkyl, cyclohexyl, aryl or aralkyl, and in which the naphthalene nucleus may be further substituted, e.g. by halogen or carboxylic or sulphonic acid groups, the components being so selected that at least one sulphonic acid group is present in the dyestuff molecule. The products yield dark violet, blue to black after-chromed shades on wool, whilst some of them may be dyed by the single bath chroming process. They may also be converted by treatment with metal salts into complex metal compounds, which dye wool and silk. Examples describe the production of the following dyestuffs: (1) 4 - nitro - 2 - aminophenol - 6 - sulphonic acid --> 2 - phenylamino-- 7 - naphthol; (2) 4 - chloro - 2 - aminophenol - 6 - sulphonic acid --> 2-phenylamino-7-naphthol; the product may be converted into its complex chromium compound; (3) 5-nitro-2-aminophenol --> 2 - phenylamino - 7 - naphthol - 6-sulphonic acid; (4) 4 : 6-dinitro-2-aminophenol --> 2 - phenylamino - 7 - naphthol - 6 - sulphonic acid; (5) 5-nitro-2-aminophenol --> 2 - hydroxyethylamino - 7 - naphthol - 6-sulphonic acid; the product may be converted into its complex chromium compound. A table gives the shades obtained with further dyestuffs, the following additional components being specified; diazo components: 2-aminophenol-4 : 6-disulphonic acid, 4-chloro-2-aminophenol-5-sulphonic acid, 6-nitro-2-aminophenol-4-sulphonic acid, 6-chloro-2-aminophenol-4-sulphonic acid, 1-amino-2-naphthol-4-sulphonic acid, 6 - nitro - 1 - amino - 2 - naphthol - 4-sulphonic acid, 5 - nitro - 2 - aminophenol - 4-sulphonic acid, 4 - chloro - 2 - aminophenol and 3 : 4 : 6 - trichloro - 2 - aminophenol; coupling components: 2 - hexahydrophenyl-, o-chlorophenyl-, o-, m- and p-methylphenyl-, p-sulphophenyl-, p- and m-carboxyphenyl-and butylamino-7-naphthol, 2-ethyl-, butyl-and o-methoxyphenylamino-7-naphthol-6-sulphonic acid. Specifications 25566/98, [Class 2], 192,438, [Class 2 (iii)], and 407,016 are referred to. N-Alkyl and N-aryl derivatives of 2-amino-7-naphthol are obtainable by reaction of 2 : 7 -dihydroxynaphthalene with the corresponding amines in the presence of sodium bisulphite solution, or by alkali fusion of the corresponding 2-alkyl or arylaminonaphthalene-7-sulphonic acid. 2-Alkyl- and arylamino-7-naphthol-6-sulphonic acids are obtainable by reacting 2 : 7 -dihydroxy-naphthalene-6-sulphonic acid with the corresponding amines in the presence of sodium bisulphite solution.