GB1274304A - Process for the electrolytic manufacture of sulphoxides - Google Patents

Abstract

1,274,304. Electrolytic process for sulphoxides. SOC., NATIONALE DES PETROLES D'AQUITAINE. 5 May, 1969 [6 May, 1968], No. 22859/69. Heading C2C. [Also in Division C7] An organic sulphoxide is produced by the anodic oxidation of the corresponding organic sulphide in a liquid medium comprising an organic solvent containing water and an electrolyte, wherein the solvent used dissolves a sufficient quantity of the electrolyte and gives a dielectric constant sufficient to produce the necessary ionic dissociation of the electrolyte, the solvent and the anion of the electrolyte having an oxidation potential which is higher than that of the sulphide, and the liquid medium is electrolysed between insoluble electrodes, the potential of the anode being maintained at a value exceeding the oxidation potential of the sulphide but below those of the solvent, anion of the electrolyte and of the sulphoxide to be produced. The electrolysis is preferably performed in a cell having one or more Pt or C anodes and one or more stainless steel or Pt cathodes, not separated by diaphragms or a cell having Pt or C anodes and C cathodes with at least one diaphragm. The anode potential is usually +0À4 to 1À7 volts and the organic solvent is suitably a dialkyl formamide, an aliphatic nitrile and/or a nitroalkane or, advantageously, the same organic sulphoxide as that which is to be prepared. The electrolyte may be an acid, e.g. sulphuric, nitric, perchloric, benzenesulphonic or toluenesulphonic acid or a salt, e.g. a halide, halogenate, perhalogenate, sulphate, nitrate or sulphonate of an alkali or alkaline earth metal. Amongst the examples, dimethyl sulphoxide is prepared by electrolysing (1) dimethyl sulphide, water, sodium p-toluenesulphonate and dimethyl formamide or (2) dimethyl sulphide, water, sulphuric acid and dimethyl sulphoxide.