GB551305A - Improvements in and relating to the preparation of hydroxy dithionaphthoic acids and their derivatives - Google Patents

Abstract

551,305. Hydroxy dithio-naphthoic acids. WINGFOOT CORPORATION. Nov. 29, 1940, No. 17080. Convention date, Nov. 29, 1939. [Class 2 (iii)] [Also in Group V] Hydroxy dithio-naphthoic acid alkali salts are prepared by reacting in a common solvent a naphthol, an alkali metal hydroxide and carbon disulphide. It is preferred that the reaction be carried out under substantially anhydrous conditions, and the water formed in the reaction be removed as it is formed. An alternative procedure comprises the separate preparation of the alkali metal naphtholate which is then reacted with carbon disulphide. Solvents mentioned include ketones, pyridine, mixtures 'of aromatic or aliphatic hydrocarbons with acetone or other ketones, and mixtures of ethers and ketones. Numerous examples are given using as starting materials both α-, and #-naphthol. Varying reaction conditions are exemplified. If alkali metal is used instead of an alkali metal hydroxide, the formation of water in the reaction is avoided. The alkali metal salts prepared as above described may be converted into the free acid by treatment with a dilute mineral acid, or they may be converted into basic zinc salts by treatment with an aqueous solution of zinc sulphate, or they may be converted into cyclohexylamine salts by reaction with ammonium chloride followed by treatment with cyclohexylamine.