Patent GB-450618-A (GB)
Title: Manufacture of azo-dyestuffs
IPC: C09B29/32
Filed: 1935-07-22
Abstract: Azo dyes; lakes; azo dyes, forming upon the material; regenerated celluloses, dyeing; printing.--Azo dyestuffs are manufactured by coupling a diazo-compound containing no solubilizing group, in substance or on the fibre, e.g. vegetable fibre or regenerated cellulose, or on another substratum, with an arylide of the general formula R1CONHR2NHCOCH2COR3 wherein R1CO-- is an acyl residue containing no CH2CO group capable of coupling, -NHR2NH-is the residue of a diamine of the diphenyl series, and --COCH2COR3 is the residue of a b -ketocarboxylic acid.  Materials may be printed with a preparation containing an alkali salt of the arylide and a stabilized diazo-compound in the form of a nitrosamine or a diazoaminocompound and developed, e.g. by passage through acid, or may be printed with a mixture of the free diazo-component or the corresponding N-nitramine and an alkali salt of the arylide and developed by means of nitrous acid and, if desired, subsequent treatment with alkali. Alternatively, the diazo-compound may be used in the form of a stable diazo-salt, e.g. a double salt obtainable by reaction of the diazo-compound with a heavy metal salt such as zinc chloride, or a salt of the diazo-compound with an aromatic sulphonic acid such as chlorobenzenesulphonic acid, a naphthalene-mono- or disulphonic acid, e.g. naphthalene-1 : 5-disulphonic acid, or a sulphonic acid of another product, e.g. a mono- or disulphonic acid of diphenyl oxide, diphenylene oxide or diphenylene dioxide.  In examples: (1) 2 : 5-dichloraniline is diazotized and coupled with p-acetyl-p<1>-acetoacetyl-o-o<1>-tolidine; (2) cotton yarn is impregnated with the coupling component of (1) and developed with diazotized 1-amino-2-methyl-4-chlorobenzene, producing a greenish-yellow dyeing.  A table shows the shades obtained with further dyestuffs, the following additional components being specified: diazo-components: o -c hloraniline, 4 - chloro - 2 - nitraniline, 4-chloro- and 4 : 4<1>- and 4 : 2<1>-dichloro-2-aminodiphenyl ether, 1-amino-2-methoxy-4-nitrobenzene, 1-amino-2-nitro-4-methylbenzene, the ethyl ester of 2-amino-4<1>-chloro - 1 : 1<1> - diphenylsulphone - 4 - carboxylic acid, 1 - amino - 2 - methoxy - 5 - chlorobenzene, anthranilic acid methyl and ethyl esters; coupling components: p-acetyl-p<1>-acetoacetylbenzidine and -o-o<1>-dichlorobenzidine. Arylides of the general formula given above are obtainable by acylating one amino-group of a diamine of the diphenyl series, e.g. benzidine, tolidine or dianisidine, by means of an acylating agent which contains no COCH2 group capable of coupling, e.g. an acetylating, chloracetylating, propionylating, benzoylating or phenoxyacetylating agent, and then reacting the second amino-group with an ester of a b -keto-carboxylic acid, e.g. an acetoacetic, benzoylacetic, terephthaloylacetic or malonic ester.  In examples: (1) monoacetylbenzidine is reacted with ethyl acetoacetate; other monoacyldiaminodiphenyls, e.g. mono-formyl- or benzoylbenzidine may be similarly treated; (2) monoacetyl-o-o<1>-tolidine, obtained by monoacetylating o-o<1>-tolidine, is reacted with ethyl acetoacetate; alternatively, the diamine is first reacted with one equivalent of ethyl acetoacetate and the free amino-group is then acylated; (3) o-o<1>-dichlorobenzidine is reacted with ethyl acetoacetate and then with acetic anhydride; alternatively, monoacetyl - o - o<1>-dichlorobenzidine is reacted with ethyl acetoacetate. 2-Amino-4<1>-chloro-1 : 1<1>-diphenylsulphone-4-carboxylic acid ethyl ester is obtainable by condensing sodium p-chlorobenzenesulphinate with 1 - chloro - 2 - nitrobenzene - 4 - carboxylic acid, esterifying the product and reducing the nitro-group.