Xanthic Acid

Xanthic Acid or Xanthogenic Acid is ethylthiolthioncarbonic acid. Its potassium salt, which is yellow and has a disagreeable smell, is prepared by the action of alcoholic potash on carbon disulphide:

CS₂ + C₂H₅OH + KOH = + H₂O.

Analogous compounds are known containing other organic alkyl radicals in place of the ethyl radical.

Xanthates are used commercially as flotation agents in "froth flotation" processes for the separation of crushed materials, and their use as vulcanisation accelerators for rubber has already been mentioned.

Xanthic acid is obtained as a colourless oil by the action of dilute sulphuric acid on the potassium salt in the cold. It decomposes at 24° C. into ethyl alcohol and carbon disulphide. The ethyl ester, when heated with water, yields carbon dioxide, hydrogen sulphide, ethyl alcohol and ethyl mercaptan, whilst with ammonia, ethyl mercaptan and xanthogenamide or thiourethane, C₂H₅O.CS.NH₂, are produced. These reactions indicate that the constitution of the acid is

and not