GB414230A - Manufacture of poly-halogen derivatives of pyrene and of pyrene quninones - Google Patents

Abstract

Polyhalogen pyrenes are obtained by the action of excess of chlorine on halogen-pyrenes containing 4--6 chlorine or bromine atoms. Polyhalogen-hydropyrenes are initially obtained and hydrogen halide is eliminated to give polyhalogen derivatives. By oxidation of these products with mineral acids, polyhalogen pyrene quinones are obtained. According to examples; (1) tetrachloropyrene, obtainable by chlorinating in trichlorobenzene, is treated with chlorine at 100 DEG C. to give a tetrachloropyrene tetrachloride, the product heated at 300 DEG C., to give off hydrogen chloride with the production of hexachloropyrene, also obtained by treating the tetrachloropyrene tetrachloride with quinoline or alcoholic potash at 100--130 DEG C.; the hexachloropyrene gives on treatment with nitric acid at ordinary temperatures, 2 : 5 : 7 : 10-tetrachloropyrene-3 : 8 quinone, which may be converted into a quinhydrone with hydrosulphite, and a dichloronaphthalene 1 : 4 : 5 : 8-tetracarboxylic acid and its anhydride, by strong oxidation; the hexachloropyrene gives a chloropyrene quinone on treatment also with fuming sulphuric acid; the same product is obtained by treating the tetrachloropyrene tetrachloride directly with fuming sulphuric acid; (2) tetrabromopyrene, obtainable by brominating in nitrobenzene at ordinary temperatures to--150 DEG C., is treated with chlorine in trichlorobenzene at up to 120 DEG C. to give a polybromopyrene polychloride, which on heating at 300 DEG C. or in a solvent or with basic agents gives a polybromo-chloropyrene with evolution of hydrogen bromide; (3) hexachloropyrene may be further chlorinated in presence of iodine at 0 DEG C. to give a perchloropyrene which decomposes on heating at 300 DEG C. to give a decachloropyrene, this yielding, on oxidation with nitric acid an octochloropyrene-3 : 8 quinone; (4) octochloropyrene obtainable as a bye-product in the preliminary chlorination of pyrene, is oxidized with nitric acid to give a hexachloropyrenequinone. The oxidation products such as those of example 1 may be used from the manufacture of naphthalene vat-dyes and the quinones may be converted by the exchange of chlorine with amino compounds, into vat dyes.