Abstract: A process for oxidizing an organic compound by ceric sulfate dissolved in an aqueous sulfuric acid solution, wherein the organic compound is oxidized (1) by means of a ceric sulfate-aqueous sulfuric acid solution or a cerous sulfate-containing ceric sulfate-aqueous sulfuric acid solution in which the molar concentration (mol/liter) of ceric sulfate is at least the molar concentration of cerium (ions) contained in the molecules of cerous sulfate at the maximum solubility of cerous sulfate in an aqueous sulfuric acid solution at the final sulfuric acid concentration (exclusive of ceric sulfate and cerous sulfate) and at the temperature under the oxidation reaction conditions and at most the saturated molar concentration of ceric sulfate in said aqueous sulfuric acid solution, (2) under a condition such that at the end of the oxidation reaction, the concentration of ceric sulfate is maintained at a level capable of dissolving cerous sulfate which is present at a concentration of at least the maximum solubility o

Abstract: Highly chlorinated copper phthalocyanine is produced by charging chlorine under an elevated pressure of 1 to 20 Kg/cm.sup.2 (gauge) into a solution of a copper phthalocyanine in the presence of pyrosulfuryl chloride and a catalyst of sulfur or sulfur chloride.Pyrosulfuryl chloride can be formed by a reaction of chlorosulfonic acid with chlorine and sulfur or sulfur chloride under an elevated pressure.An auxiliary catalyst of iodine, iodine chloride or a metal chloride can be incorporated to improve the chlorination.

Abstract: In a process for separation of naphthoquinone and phthalic acid from an aqueous slurry prepared by contacting a reaction mixture gas formed by a catalytic vapor phase oxidation of naphthalene with an aqueous medium, the decomposition of naphthoquinone is prevented and phthalic acid is substantially separated by adding a base to the aqueous slurry so as to neutralize only sulfuric acid component and maleic acid component without substantially neutralizing phthalic acid component and heating the aqueous slurry to dissolve phthalic acid to form a slurry of naphthoquinone in an aqueous solution of phthalic acid and extracting naphthoquinone with a solvent while preventing a crystallization of phthalic acid.A pH of the aqueous slurry is adjusted in a range of 1.2 to 2.5 before the heat dissolution of phthalic acid and the extraction of naphthoquinone.