GB616507A - Manufacture of monoazo-dyestuffs - Google Patents

Abstract

Asymmetrical urea derivatives of aminonaphtholmonosulphonic acids (containing the group -NHCONH2) are obtained by treating the sodium salt of the acid with an alkali cyanate.ALSO:Monoazo dyestuffs, which dye wool from an acid bath, are manufactured by coupling a diazotized sulphonated amine of the benzene series (especially an aminobenzene-o-sulphonic acid which may contain further substituents, e.g. halogen atoms, alkyl radicals or nitro groups) with an aminonaphtholmonosulphonic acid, capable of coupling in o-position to the hydroxy group, in which the amino and hydroxy groups are not in peri-position to one another and of which the amino group contains as a substituent the group -CO.NH2. Examples describe the preparation of the following dyestuffs: (1) 1-aminobenzene-2-sulphonic acid --> mono - 2 - (8 - hydroxy - 6 - sulpho) - naphthyl - urea; (2) 1-aminobenzene-2-, -3- or -4-sulphonic acid or 1-amino-4-ethoxybenzene-2-sulphonic acid --> mono-2-(5-hydroxy-7-sulpho)-naphthylurea; (3) 1 - amino - 4 - chloro- or -methyl - benzene-2-sulphonic acid --> the coupling component of (2). In example (4), wool is dyed orange with the first dyestuff of (2) or yellowish red with the dyestuff of (1) from a bath containing sodium sulphate and sulphuric acid. Additional components specified are: diazo components: 1-amino-5-nitrobenzene-2-sulphonic acid and 1-amino-4-methyl-5-chlorobenzene - 6 - sulphonic acid; coupling components: the urea derivatives of 2 : 6 : 8- and 1 : 5 : 7-aminonaphtholsulphonic acids. The Specification as open to inspection under Sect. 91 comprises also the use of any other desired diazo components and of urea derivatives of other aminonaphthol sulphonic acids capable of coupling in o-position to the hydroxy group. This subject-matter does not appear in the Specification as accepted.