Patent GB-362965-A (GB)
Title: Improvements in the manufacture and production of derivatives of the 1.2-benzanthraquinone series
IPC: C09B3/58
Filed: 1930-09-08
Abstract: Dyes and intermediates of the 1.2-benzanthraquinone series.  A Bz4-halogen-1.2-benzanthraquinone is treated with chlorine or bromine or agents supplying these halogens in the presence of inorganic strongly acid agents, such as dilute, concentrated, and fuming sulphuric acids, halogen sulphonic acids, and aluminium halides.  If desired, catalysts such as iron salts, iodine, sulphur and tertiary bases, and further organic diluents may also be present.  The preparation of the Bz4 halogen-1.2-benzanthraquinone and their further treatment may be combined in one operation by first halogenating in an organic diluent and then adding the inorganic acid agent and continuing halogenation.  These products are dye intermediates and different from those obtained according to the processes of Specifications 18616/08, [Class 2, Acids and salts, Organic &c.], 254,476, [Class 2 (iii), Dyes &c.], and 362,482; their halogen content may be increased by chlorination in an organic diluent and splitting off hydrogen chloride according to the process of Specification 362,482.  By heating these halogenated -1.2-benzanthraquinones with copper or mercury preferably in presence of an organic diluent, halogen-1.2-di-benzanthraquinonyls are produced; if, however, this heat treatment is carried out at comparatively high temperatures blue to grey vat dyes admixed with non-dyeing products are obtained.  These halogen-1.2-di-benzanthraquinonyls are converted into vat dyes by treating with acid condensing agents such as sulphuric acid or aluminium chloride, in the presence or not of diluents.  Or alternatively the halogen-1.2-di-benzanthraquinonyl is first reduced to the leuco derivative and as such, or in the form of an ether or ester derivative thereof, is acid condensed; a modification of this latter process is to treat the di-benzanthraquinonyl with an acid condensing agent containing reducing agents, such as zinc or copper. These latter treatments require a much lower temperature to effect conversion to the dye.  In examples (1) Bz4-bromo-1.2-benzanthraquinone (prepared by brominating 1.2-benzanthraquinone in glacial acetic acid) is brominated in a solution of chlorsulphonic acid and pyridine by means of bromine or potassium bromide to give a dibromo compound; it is chlorinated in chlorsulphonic acid and pyridine, a little sulphur being present as catalyst, or in sulphuric acid, or in a mixture of aluminium chloride and nitrobenzene to give a chloro-Bz4-bromo-1.2-benzanthraquinone: (2) Bz4 - chloro - 1.2 - benzanthraquinone (prepared by sulphonating 1.2-benzanthraquinone and chlorinating the product in aqueous solution) is brominated in a solution of chlorsulphonic acid and pyridine, and chlorinated in this solution in the presence of p sulphur as catalyst: (3) 1.2-benzanthraquinone is treated with bromine in nitrobenzene, excess halogen is removed, aluminium chloride added and the product chlorinated: (4) the chlor-Bz4-bromo-1.2-benzanthraquinone of (1) is chlorinated in carbon tetrachloride in presence of actinic light such as sunlight; the product, on boiling in pyridine, is a trichloro-1.2-benzanthraquinone: (5) the chlor-Bz4-brom-1.2-benzanthraquinone of (1) above is heated with copper powder alone or in benzophenone to give a dibromo-1.2-di-benzanthraquinonyl; the same product is obtained by heating the dibromo-1.2-benzanthraquinone of (1) above with copper powder in trichlorbenzene or acetic anhydride, or with mercury in benzophenone: (6) the bromo-Bz4-chloro-1.2-benzanthraquinone of (2) above is heated with copper powder in trichlorbenzene: (7) the dibromo-1.2-benzanthraquinone is boiled in benzophenone with copper; the residue contains a blue and a grey dyestuff which are easily separable by virtue of their different solubilities in organic solvents: (8) the dibromo-1.2-di-benzanthraquinonyl of (5) above is heated at 160-170 DEG  with strong sulphuric acid, or heated to 40 DEG  in sulphuric acid containing a little copper, or heated to 165-175 DEG  in a mixture of aluminium chloride and pyridine, or in an aluminium-sodium chloride melt; a product containing bromine and dyeing violet shades from the vat is obtained in each case: (9) the dichloro-1.2-di-benzanthraquinonyl of (6) above is heated to 165-175 DEG  in a mixture of aluminium chloride and pyridine to give a chlorine containing violet dye: (10) the methyl ether of dibromo - 1.2 - di - benzanthrahydroquinonyl (prepared by treating the dibromo-1.2-di-benzanthraquinonyl with zinc dust, soda and toluene sulphonic acid methyl ester in trichlorbenzene) is treated with cold concentrated sulphuric acid to give the dyestuff of (8) above in pure form; instead of the above methyl ether may be used the corresponding sulphuric ester (prepared by treating dibromo-1.2-di-benzanthraquinonyl with copper and sulphur trioxide in pyridine) or the free leuco compound; these processes are equally applicable to the dichloro-1.2-di-benzanthraquinonyl to give the same dyestuff as in (9) above: (11) the dibromo-1.2-di-benzanthraquinonyl is treated with tin in a mixture of glacial acetic and hydrochloric acids and the product (probably a dibromo-1.2-di-benzoanthronyl) is heated to 60-70 DEG  in a mixture of aluminium chloride and pyridine to give the dyestuff of (8) above.  The oxygen-containing reduction products of the halogen-1.2-di-benzanthraquinonyls employed in the process are in general prepared by the customary methods.