Patent GB-414483-A (GB)
Title: Manufacture of new azo-dyestuffs
IPC: C09B29/00
Filed: 1933-05-15
Abstract: Azo dyes are prepared by coupling with any coupling component a diazotized phenyl (or substituted phenyl) ester of 4-nitro (or 4-acylamino) aniline-2-sulphonic acid.  The nitro or acylamino group in the products may be reduced or saponified respectively, and the amino group in the reduced dyes may be acylated.  Coupling components specified as suitable are amino compounds, particularly 2-naphthylamine or its derivatives or substitution products, such as ethyl-2-naphthylamine or its sulphonic acids, or 2-amino-8-naphthol-6-sulphonic acid.  In examples of the preparation of diazo compounds and dyes, (1) a solution of sodium nitrite in sulphuric acid is warmed to 65 DEG  C., cooled, and treated with 4-nitraniline-2-sulphonic acid phenyl ester; the diazo compound separates and may be filtered; other acids such as formic or acetic acid may replace sulphuric acid; an aqueous feebly acid suspension of the diazo compound is treated with a neutralized solution of 2-amino-8-naphthol-6-sulphonic acid with optional addition of sodium acetate; a water-soluble dye giving violet-blue tints on wool in an acid bath is obtained; similar dyes are obtained from diazotized 4-nitraniline-2-sulphonic acid esterified with chlorophenols, cresols, nitrophenols, aminophenols and acylaminophenols; (2) diazotized 4-acetylaminoaniline-2-sulphonic acid p-chlorophenyl ester is coupled with 2-amino-8-naphthol-6-sulphonic acid; the product gives blue-red tints on wool in an acid bath; the same dye is obtained when the dye from diazotized 4-nitraniline-2-sulphonic acid p-chlorophenyl ester and 2-amino-8-naphthol-6-sulphonic acid is reduced with sodium sulphide and then acetylated.  In examples of dyeing processes, (3) wool is dyed in a hot aqueous bath containing sodium sulphate, acetic acid, and the first dye described in example 1; (4) wool is dyed in a hot aqueous bath containing sodium sulphate, sulphuric acid, and the dye described in example 2.  Aryl esters of 4-nitro (or 4-acylamino) aniline-2-sulphonic acids. The ester of 4-nitraniline-2-sulphonic acid with phenol is prepared from phenol and 4-nitraniline-2-sulphonyl chloride, which is obtainable from the acid and a phosphorus chloride.  The esters of 4-nitraniline-2-sulphonic acid with chlorophenols, cresols, nitrophenols, aminophenols and acylaminophenols are obtainable similarly.  4-Acetylaminoaniline-2-sulphonic acid p-chlorophenyl ester is prepared from the corresponding ester of 4-nitraniline-2-sulphonic acid by reduction in alcohol with iron and acetic or hydrochloric acid and subsequent acetylation.  The Specification as open to inspection under Sect. 91 refers to the use of the following components: (a) components containing a COCH2 group, such as acetoacetic anilide and other arylides, acetoacetic ester, and pyrazolones such as 1-phenyl-3-methyl-5-pyrazolone; (b) salicylic acid, cresotinic acids, naphthols, and 2-naphtholsulphonic acids; (c) 2-amino-8-naphthol, 2-naphthylamine-6-sulphonic acid, 2-amino-5-naphthol-7-sulphonic acid and their N-alkyl, N-aralkyl, and N-aryl substitution products or similar substitution products of 2 - amino - 8 - naphthol - 6 - sulphonic acid; (d) dimethylaniline and other dialkylanilines, diphenylamine and its carboxylic and sulphonic acids, ethylbenzylaniline and its sulphonic acids, benzylnaphthylamines, 1 - tolylamino - naphthalene-8-sulphonic acid, 1-amino-5-naphthol-7-sulphonic acid, 1-naphthylamine, ethyl-1-naphthylamine, and 2-amino-8-naphthol-3 : 6-disulphonic acid. Further, the Specification amplifies the examples given above as follows: (a) in example 1, use may be made of the diazo compounds from esters of 4-nitraniline-2-sulphonic acid with monoalkyl ethers of dioxybenzenes, such as guaiacol or the monomethyl ethers of resorcinol or hydroquinone; these esters are obtainable similarly to the esters described above; dyes similar to that described in example 1 are obtained by using as coupling components other aminonaphtholsulphonic acids such as 2-amino-8-naphthol-3 : 6-disulphonic acid or 1-amino-5-naphthol-7-sulphonic acid; yellow pigment dyes are obtained when acetoacetic ester, acetoacetic arylides or phenylmethylpyrazolones are used as coupling components, while ethyl- or benzyl-1- or -2-naphthylamine yield blue pigment dyes; (b) in example 2, dyes similar to that described are obtained by using 1-amino-5-naphthol-7-sulphonic acid and 1-tolylaminonaphthalene-8-sulphonic acid as coupling components; dialkylanilines, ethylbenzylaniline, diphenylamine, 2-naphthol and salicylic acid, used as coupling components, yield dyes giving yellow to orange tints on wool.  The Specification includes also the following examples: (1) the ester from 4-nitraniline-2-sulphonic acid and p-cresol-o-sulphonic acid (obtained similarly to the esters described above), is diazotized and coupled with 2-amino-8-naphthol-6-sulphonic acid to yield a water-soluble violet blue dye; a similar but less soluble dye is obtained when ethyl - 2 - naphthylamine hydrochloride or sulphate is used as a coupling component; (2) the ester from 4-acetylaminoaniline-2-sulphonic acid and p-cresol-o-sulphonic acid (obtained similarly to the 4-acetylaminoaniline-2-sulphonic acid p-chlorophenyl ester described above) is diazotized and coupled with ethyl-2-naphthylamine hydrochloride or sulphate to yield a red dye; ethyl-1-naphthylamine as coupling component gives a blue dye; 2-naphthylamine, diphenylamine, 2-naphthol, and salicylic acid yield yellow to red dyes.  The Specification states also that the dyes containing sulpho groups may be applied to silk or loaded silk, and that the non-sulphonated dyes may be used for colouring varnishes, cellulose ester lacquers, and artificial masses.  This subject-matter does not appear in the Specification as accepted.