GB497745A - Process for the manufacture of azodyestuffs - Google Patents

Abstract

Azo dyestuffs are manufactured by diazotizing the disazo dyestuffs, obtained by tetrazotizing monoaminobenzoylated diamines of the benzene series and coupling first with an o-hydroxycarboxylic acid of the benzene series and secondly with an aminonaphthol mono- or disulphonic acid, and coupling the resulting diazo compounds with m-diamino-, m-aminohydroxy- or m-dihydroxy-compounds of the benzene series or the monoazo derivatives thereof. The products dye cotton reddish to deep blackish-brown shades of good neutral and alkaline dischargeability. The dyes may be after-treated on the fibre, e.g. with formaldehyde if one coupling component is a free diamine, or with diazo compounds such as those from m- or p-nitraniline or 1-amino-2-methoxy-4-nitrobenzene. Examples describe the production of the following dyestuffs: (1) a mixture of salicylic and o-cresotinic acid \sM p - aminobenzoyl - p - phenylenediamine --> 2 : 8 : 6 - acid --> m - phenylenediamine; the product dyes cotton deep brown shades which may be after-treated with formaldehyde; the m-phenylenediamine may be replaced by the sodium salt of the dyestuff sulphanilic acid --> m-phenylenediamine (deep brown shades dischargeable by alkaline or neutral agents), or by the chrysoidine from 1-naphthylamine-4-sulphonic acid and m-phenylenediamine (bluish-brown) or by 1 : 3-phenylenediamine-4-sulphonic acid, and the 2 : 8 : 6-acid by 2 : 5 : 7- or 2 : 8 : 3 : 6-acids; the dyeings may be developed with diazotized p-nitraniline to deep yellowish-brown shades; (2) salicylic acid \sM p-aminobenzoyl-p-phenylenediamine --> 2 : 8 : 6-acid --> resorcinol (reddish-brown shades dischargeable by neutral and alkaline agents and becoming more reddish on treatment with formaldehyde), or the dyestuff metanilic acid --> resorcinol (more bluish-red shades which may be developed with diazotized p-nitraniline to brown shades), or m-aminophenol. Specification 8144/09, [Class 2 (iii)], is referred to.