Abstract: Sulphoxides of thioformamide derivatives of the formula: ##STR1## wherein R represents hydrogen or a C.sub.1 -C.sub.4 alkyl radical, Het represents a heterocyclic radical selected from pyridin-3-yl (optionally substituted by a C.sub.1 -C.sub.4 alkyl radical or by a halogen atom), quinolin-3-yl, pyridazin-4-yl, pyrimidin-5-yl, thiazol-5-yl, thieno[2,3-b]pyridin-5-yl and thieno[3,2-b]pyridin-6-yl, and Y represents a valency bond or a methylene radical, are prepared by oxidizing the ring sulphur atom of a thioformamide derivative of the general formula: ##STR2## by an electrochemical method. The reaction is carried out in an electrolyte with a considerable water content, at a pH of between 7 and 7.5 and in the presence of a specific oxidizing agent X.sup.+ obtained in situ from a halide X.sup.- by an electrochemical method, and at an imposed electrode potential similar to the oxidation potential of X.sup.-.The sulphoxide products are useful as medicaments for treating hypertension.

Abstract: A process and apparatus for purification of a sodium chloride solution dialysis liquid in which the liquid is subjected to an electrolysis.