GB486302A - New monoazo dyestuffs - Google Patents

Abstract

Monoazo dyes, suitable for colouring acetate artificial silk, are obtained by coupling, in acid medium, a diazotized nitroamine of the formula <FORM:0486302/IV/1> wherein X is hydroxyl and Y hydrogen or X is halogen and Y hydrogen or halogen, with an N - substituted 1 : 5 - aminonaphthol of the formula <FORM:0486302/IV/2> in which R1 stands for hydrogen or alkyl (containing not more than 4 carbon atoms) and R2 for sulphatoethyl or sulphatopropyl (where ethyl or propyl may be further substituted by halogen). Alternatively, the diazotized nitroamine may be coupled with the corresponding 1 - N - hydroxyalkylamino - 5 - naphthol and the sulphato group introduced subsequently by treatment with a suitable agent, e.g. sulphuric acid. The products dye acetate artificial silk blue shades from acid, neutral or alkaline baths; they may also be used for printing. In examples, (1), (2) and (3) 2-chloro-4-nitraniline, 2-bromo-4-nitraniline, 5-nitro-2-aminophenol, 2 : 5-dichloro- and 2 : 5-dibromo-4-nitraniline are diazotized and coupled with the sodium salt of the alkyl sulphuric ester of 1-N-b -hydroxy-ethylamino-5-naphthol; (4) 2-chloro-4-nitraniline is diazotized and coupled with the sodium salt of the alkyl sulphuric ester of 1-N-g -hydroxypropylamino - 5 - naphthol; (5) and (6) 2 - chloro- and 2 - bromo - 4 - nitraniline are diazotized and coupled with 1-N-b -hydroxy-ethylamino-5-naphthol in acid medium and the insoluble products added slowly to 80 per cent sulphuric acid to effect esterification. The sodium salt of the alkyl sulphuric ester of 1 - N - g - chloro - b - hydroxypropylamino - 5-naphthol and 1-N-b -hydroxyethyl-N-n-butylamino-5-naphthol are also specified as coupling components, the latter being sulphonated after coupling. Specifications 181,750 and 237,739, [both in Class 2 (iii)], are referred to. 1-N-b -hydroxyethyl - N - n - butylamino-5-naphthol is obtained by reacting 1-N-b -hydroxyethylamino - 5 - naphthol with excess of n-butyl bromide in aqueous alcohol in the presence of chalk. 1-N- g - chloro - b - hydroxypropylamino-5-naphthol is obtained by reacting 1 : 5-aminonaphthol and epichlorhydrin in a solvent, e.g. alcohol, at 75-120 DEG C.