Ethyl-sulphone-acetic acid, C2H5SO2 – CH2 – COOH, was prepared by Claesson's method. Fourteen grams of the potassium salt were dissolved in 20 c.c. of water, and the solution electrolysed for 30 minutes under following conditions:—Volts, 12; ampères, 3·4; temperature, 30°–35° C.

Carbonic anhydride and hydrogen were given off, and a white solid substance separated. This was collected on a filter and washed with cold water. The product, when dry, weighed 1·7 gram. It was purified by recrystallisation from chloroform.

It forms needles, melting at 136°–137°.