GB362482A - Improvements in the manufacture and production of intermediate products and dyestuffs of the 1.2-benzanthraquinone series - Google Patents

Abstract

Dyes and intermediates of the 1.2-benzanthraquinone series are obtained by the action of chlorine or chlorinating agents on 1.2-benzanthraquinone or its derivatives in the presence of organic diluents and in the absence of inorganic strongly acid agents, and splitting off hydrogen chloride by known methods from the chlorine addition products thus obtained. Thus, such splitting off may be effected by heating alone, or in organic diluents, or by treatment with inorganic or organic bases, acids or salts, which processes may be effected in one operation with the preparation of the chlorine addition products. The chlorination may be accelerated by chemically active rays, such as p sunlight or ultra-violet light; in some cases other reactions than addition of chlorine may also take place, such as chlorine substitution in hydroxy- or alkoxy-1.2-benzanthraquinones, replacement of bromine by chlorine in bromo-1.2-benzanthraquinones, and a saponification in the case of ethers of 1.2-benzanthraquinones. Similarly the splitting off of hydrogen chloride may be attended by other reactions. In examples (1) chlorine is led through 1.2-benzanthraquinone in carbon tetrachloride, and the precipitated reaction product heated above its melting point, or boiled in pyridine to give a dichloro-1.2-benzanthraquinone; (2) 1.2-benzanthraquinone is chlorinated in nitrobenzene, excess chlorine removed from the solution, pyridine added, and the mixture heated; the product is a dichloro-1.2-benzanthraquinone; (3) 3-chloro-1.2-benzanthraquinone (prepared by condensing phthalic anhydride with a -chloronaphthalene and ring-closing by means of sulphuric acid) is chlorinated in chloroform, the reaction product precipitated, and heated in a solution of alcoholic potash; (4) 3-methoxy-1.2-benzanthraquinone prepared by condensing phthalic anhydride with a -naphthol methyl ether and ring-closing by means of phosphorus pentoxide) or 4-chloro-3-methoxy-1.2-benzanthraquinone (prepared by chlorinating the 3-methoxy derivative by means of sulphuryl chloride) is chlorinated in chloroform; in either case the final product is the same, a chlorinated hydroxy derivative, and this is heated at 250-260 DEG in benzophenone, or above its melting point in the absence of a solvent, to give a product dyeing cotton red-brown shades from the vat; it is stated that the product is probably a condensation of two molecules by sharing the hydroxy groups and splitting off hydrogen chloride; (5) Bz4-chloro- or Bz4-bromo-1.2-benzanthraquinone is treated as in (2) to give a trichloro-1.2-benzanthraquinone in each case; this product dyes cotton yellow shades from the vat. The splitting off of halogen hydrides may also be carried out by boiling the nitrobenzene solution of the chlorine addition product, or by heating this solution with aluminium chloride, or by stirring it with ground potash at room temperature instead of heating with pyridine.