Patent GB-347609-A (GB)
Title: Process for production of colouring matters
IPC: C09B29/20
Filed: 1930-01-28
Abstract: Azo dyes; azo dyes, forming on the material; lakes.-Azo dyes are produced in substance, on a substratum, or on the fibre by treating compounds of the type X-R-NH-CO-R1-Y (in which R is arylene, R1 is arylene or the residue of the enol form of a ketocarboxylic acid, and X and Y are hydroxy or amino groups, there being at least one amino group and Y being always hydroxy when R1 is other than arylene) with nitrous acid under such conditions that diazotization is effected, and thereafter treating with reagents which cause the diazotized compound to couple with itself.  Monoazo, disazo, trisazo, and higher polyazo products are thus obtainable.  Specified compounds are aminoanilides of salicylic acid, of 2 : 3-oxynaphthoic acid, of pyrazolonecarboxylic acids such as 1-phenyl- or 1-(31-or 41-nitro) phenyl-5-pyrazolone-3-carboxylic acid, of acetoacetic acid, and of aminobenzoic acids, and monosalicylbenzidines.  Thus the m-aminoanilide of 2 : 3-oxynaphthoic acid yields a red, the corresponding p-aminoanilide a bordeaux, monosalicylbenzidine a yellow, the m-aminoanilide of salicylic acid a yellow, and monoacetoacetyltolidine a yellow dyestuff.  The following examples are specified: (1) A solution of the m-aminoanilide of 2 : 3-oxynaphthoic acid in dilute caustic soda is slowly mixed into a solution of sodium nitrite acidified with acetic acid; a red pigment is precipitated; (2) A fabric of cotton, wool, or artificial silk (e.g. collodion silk, viscose silk, or other regenerated cellulose, or acetate silk), is padded with a solution of the m-aminoanilide of 2 : 3-oxynaphthoic acid in dilute caustic soda, acidified or neutralized with acetic acid, and introduced into sodium nitrite solution to obtain a red dyeing.  Aminoarylamides of the above general formula are obtainable (a) by reducing the nitroarylides of the types NO2-Aryl-NH-CO-Aryl-OH, HO-Aryl-NH.CO-Aryl-NO2, and NO2-Aryl-NH-CO-Aryl-NO2, e.g. with sodium sulphite, alkali stannite, ferrous chloride, or free hydrogen, (b) by condensation of 1 mol. of a diamine with 1 mol. of an oxycarboxylic acid chloride preferably by heating with the acid in a solvent such a toluene, solvent naphtha, melted naphthalene, or pyridine, in presence of a condensing agent such as phosphorus trichloride; the diamine may be monoacidylated, e.g. by introducing an acetyl or p-toluenesulphonyl group prior to the condensation, the acidyl group being subsequently removed by hydrolysis; thus monoacetoacetyltolidine may be obtained either by the action of ethylacetoacetate on tolidine or by careful partial saponification of the acetylacetoacetyltolidine obtainable by the action of ethyl acetoacetate on monoacetyltolidine.  The following examples of the production of the aminoarylides are specified: (1) The m-nitranilide or the m-nitrotoluidide (CH3 : NH2 : NO2 = 1 : 2 : 4) of 2 : 3-oxynaphthoic acid is reduced by heating with sodium sulphide solution and the aminoarylide precipitated by acidification; (2) 1 mol. of m-phenylene- or m-toluylene-diamine is mixed with 1 mol. of 2 : 3-oxynaphthoic acid and phosphorus trichloride in toluene, the mixture is boiled until evolution of hydrogen chloride ceases, sodium carbonate is added in slight excess, and the toluene is distilled off; (3) 1 mol. of m-nitraniline is condensed with 1 mol. of salicylic acid as in (2) and the product reduced as in (1); (4) 1 mol. of benzidine is condensed with 1 mol. of salicylic acid as in (2); the product is purified from unchanged benzidine by dissolving in dilute caustic soda, filtering, and acidifying the filtrate; (5) 1 mol. of m-nitrobenzoic acid is condensed with 1 mol. of m-nitraniline as in (2), the product is reduced with sodium sulphide or alkaline stannous chloride, and the aminoarylide is precipitated by acidification.  1-phenyl-3-pyrazolone-5-carboxylic acid-m-aminoanilide is obtained by condensing 1 mol. of m-nitraniline with 1 mol. of 1-phenyl-5-pyrazolone-3-carboxylic acid as in (2) and reducing the product.  The Provisional Specification describes also the use of the p-aminoanisidide of 2 : 3-oxynaphthoic acid, the p-aminoanilide of salicylic acid, and the 1-oxy-8-naphthylamide of m-aminobenzoic acid and refers to the use of stannous chloride for the reduction of nitro groups.