GB189712011A - The Manufacture or Production of New Anthraquinone Dye-stuffs. - Google Patents

Abstract

12,011. Newton, H. E., [Farbenfabriken vorm. F. Bayer & Co.]. May 14. Disulphonic acids of dinitroanthrarufin and of dinitroanthrachrysazin are preparing by first converting anthrarufin and anthrachrysazin into disulphonic acids by treatment with fuming sulphuric acid containing 2 per cent. of free sulphuric anhydride at about 100‹-120‹ C., and then diluting with sulphuric acid of 60‹ BÚ. and adding a mixture of sulphuric and nitric acids, while the temperature is kept at 20‹-30‹C. The precipitate obtained upon cooling is dissolved in hot water and by addition of potassium chloride the potassium salt of the dinitro-disulphonic acid is obtained in the form of yellow crystals soluble in water. Dyes, artificial.-(1) Disulphonic acids of p-diamidoanthrarufin and of diamidoanthrachrysazin, which dye unmordanted wool in acid baths fast even blue shades, and chrome-mordanted fibres greenish-blue shades, are obtained as follows :- The foregoing potassium salts of the disulphonic acids of dinitroanthrarufin or of dinitroanthrachrysazin are reduced to the disulphonic acids of the corresponding diamido compounds by acting upon them with stannous chloride and hydrochloric acid. The new dyes separate as a gelatinous mass which is converted into a precipitate of fine needles by heating it upon a water bath. The dyes may also be produced upon the fibre by dyeing wool in an acid bath with the dinitrodisulpbonic acids and then impregnating the fibre with a suitable reducing-agent. (2) Monosulphonic acids of p-diamidoanthrarufin and of p-diamidoanthrachrysazin are produced by sulphonating the diamiclo compounds by heating them with a mixture of fuming sulphuric acid, containing 30 per cent. of free SO3, and boric acid at 100‹-130‹ C. The mixture, when cool, is poured.into a large quantity of water and boiled, and the precipitate is filtered off. The monosulphonic acids are similar in dyeing properties to the disulphonic acids.