GB925818A - Process for the manufacture of low-molecular weight dialkyl sulphoxides - Google Patents

Abstract

Dialkyl sulphoxides in which the alkyl radicals contain 1 to 4 carbon atoms are prepared by liquid-phase oxidation of the corresponding dialkyl sulphides by oxygen or gas mixtures containing free oxygen in the presence of nitrogen oxides as oxygen-carriers, the gases involved in the reaction being so finely dispersed and mixed in the liquid phase by agitation of the reaction mixture that a dispersed quantity of gas of at least 7% by volume, based on the liquid, is established in the liquid phase. The process may be carried out continuously or discontinuously and in one or more stages. The dispersion of the gases in the liquid phase is accomplished by vigorous agitation with a high-speed agitator, or by ultra-sonic waves. In the continuous process a mixture of dialkyl sulphide, dialkyl sulphoxide and oxygen-carrier is agitated whilst passing in a mixture of dialkyl sulphide and oxygen-containing gas and simultaneously removing a corresponding amount of liquid from the reaction mixture, the oxygen-carrier being replenished as necessary. The unreacted dialkyl sulphide and the oxygen-carrier may be recirculated. In Examples: (1)-(3) and (5) dimethyl sulphide is oxidised to dimethyl sulphoxide; (4) diethyl sulphide is oxidised to diethyl sulphoxide. Other specified reagents are dipropyl, dibutyl, methylethyl, methylpropyl, ethylpropyl, ethylbutyl and propylbutyl sulphides. Specification 737,575 is referred to.