Potassium Ethyl Xanthate (CAS: 140-89-6)

Potassium ethyl xanthate is an organosulfur compound with the chemical formula CH3CH2OCS2K.

It is a pale yellow powder that is used in the mining industry for the separation of ores. Unlike the related

sodium ethyl xanthate, the potassium salt exists as an anhydrous salt.

Production and properties

Xanthate salts are prepared by the action of alcohols on carbon disulfide. The alkoxide is generated

in situ from potassium hydroxide:

CH3CH2OH + CS2 + KOH → CH3CH2OCS2K + H2O

Potassium ethyl xanthate is a pale yellow powder that is relatively stable at high pH but rapidly hydrolyses at

pH<9 at 25 °C. Unlike the sodium derivative, potassium xanthate crystallizes as the anhydrous salt and is nonhygroscopic.

Applications

Potassium ethyl xanthate is predominantly used in the mining industry as flotation agent for extraction of

the ores of copper, nickel, and silver. The method exploits the affinity of these “soft” metals for the organosulfur

ligand. Potassium xanthate is a useful reagent for preparing xanthate esters from alkyl and aryl halides. The resulting

xanthate estes are useful intermediates in organic synthesis.