Patent GB-451100-A (GB)
Title: The manufacture of disazo dyestuffs
IPC: C09B35/28
Filed: 1934-08-02
Abstract: Azo dyes; azo dyes, forming upon the material.--Disazo dyestuffs are manufactured by coupling diazotized nitroaroyl-m- or p-diamines with aromatic o-hydroxycarboxylic acids containing no amino groups or 1-aryl-5-pyrazolone-3-carboxylic acids or esters thereof containing no amino groups, reducing the nitro group, further diazotizing and coupling with 1-aryl-5-pyrazolone-3-carboxylic acids which may be substituted in the 1-aryl nucleus, or derivatives thereof, or with aminonaphtholsulphonic acids substituted in the amino group, e.g. N-alkyl-, N-aryl-, N-acyl- or N-aroyl- 2 : 5 : 7-acid. Alternatively in place of the diazotized nitroaroyldiamines there is used a diazotized m- or p-nitroarylamine or acylaminoarylamine, and after the first coupling the nitro group is reduced or the acylamino group saponified and the amino group thus formed is condensed with a nitroaroyl chloride.  The products dye cotton yellow to red shades easily dischargeable in the neutral or alkaline process.  When the second coupling component contains a diazotizable amino group, the dyestuffs can be diazotized and developed in substance or on the fibre.  In examples: (1) p-nitrobenzoyl-p-phenylenediamine is diazotized and coupled with 1-phenyl-5-pyrazolone-3-carboxylic acid and the product is reduced, diazotized and coupled with 1-phenyl-5-pyrazolone-3-carboxylic acid; the product dyes cotton orange shades; as second coupling component there may alternatively be used 1-(m- or p-nitrophenyl)-5-pyrazolone-3-carboxylic acid, the dyestuffs being subsequently reduced; the products may be diazotized on the fibre and developed with 1-phenyl-3-methyl-5-pyrazolone, yielding yellow-orange and brown red shades respectively, or with b -naphthol, yielding red-orange and brown red shades; (2) the dyestuffs p-nitraniline or acetyl-p-phenylene diamine --> salicylic acid are reduced or saponified respectively and the product is condensed with p-nitrobenzoyl chloride, reduced, diazotized and coupled with 1-phenyl-5-pyrazolone-3-carboxylic acid; the product dyes cotton reddish yellow shades; if the second coupling component be replaced by 1-(m-aminophenyl)-5-pyrazolone-3-carboxylic acid, p-aminobenzoyl-J-acid or N-p-aminobenzoyl-N-methyl-J-acid, the products may be developed on the fibre, yielding yellower shades than in (1); the product from 1-(m-aminophenyl)-5-pyrazolone-3-carboxylic acid may be diazotized in substance and coupled with 1-(p-sulphophenyl)-5-pyrazolone-3-carboxylic acid or 1-(m-aminophenyl)-3-methyl-5-pyrazolone; the products yield respectively reddish-yellow and yellow dyeings on cotton, the latter of which may be rendered fast to washing by after-treatment with diazotized p-nitraniline or formaldehyde, or may be diazotized and developed, e.g. with b -naphthol yielding a yellow-orange; if the p-nitrobenzoyl chloride be replaced by the m-compound, more greenish yellow dyestuffs are obtained; (3) p-nitrobenzoyl-p-phenylene diamine is diazotized and coupled with 1-(6<1>-sulpho-2<1>-naphthyl)-5-pyrazolone-3-carboxylic acid ester and the product is reduced, diazotized, and coupled with benzoyl-J-acid; the product dyes cotton scarlet shades; the second coupling component may be replaced by 1-m-aminophenyl-5-pyrazolone-3-carboxylic acid or p- or m-aminobenzoyl-J-acid, yielding dyestuffs somewhat redder than those of (1).  Specifications 14315/09 and 7303/13, [both in Class 2 (iii)], and 442,672 are referred to.