Potassium ethyl xanthate
Potassium ethyl xanthate is an organosulfur compound with the chemical formula. It is a pale yellow powder that is used in the mining industry for the separation of ores. It is a potassium salt of ethyl xanthic acid. Many xanthates are known.
Production and properties
Xanthate salts are prepared by the action of alkoxides on carbon disulfide. The alkoxide is often generated in situ from potassium hydroxide:The salt, prepared from potassium pentanolate and carbon disulfide has been characterized by X-ray crystallography. The COCS2 portion of the anion is planar. The C-S bond lengths are both 1.65 Å, and the C-O distance is 1.38 Å.
Potassium ethyl xanthate is a pale yellow powder that is stable at high pH, but rapidly hydrolyses below pH = 9:
Oxidation of xanthate salts gives diethyl dixanthogen disulfide:
KEX is a source of ethylxanthate coordination complexes. For example, the octahedral complexes,, and have been prepared from KEX.
Applications
Potassium ethyl xanthate is 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 ethyl xanthate is a useful reagent for preparing xanthate esters from alkyl and aryl halides. The resulting xanthate esters are useful intermediates in organic synthesis.