Potassium ethyl xanthate

Potassium ethyl xanthate
IUPAC name potassium O-ethylcarbonodithioate
Other names potassium ethylxanthogenate potassium-O-ethyl dithiocarbonate
Identifiers
CAS number	140-89-6 Y
PubChem	2735045
ChemSpider	8491 Y
Jmol-3D images	{{#if:[K+].[S-]C(=S)OCC|Image 1
SMILES [K+].[S-]C(=S)OCC
InChI InChI=1S/C3H6OS2.K/c1-2-4-3(5)6;/h2H2,1H3,(H,5,6);/q;+1/p-1 Y Key: JCBJVAJGLKENNC-UHFFFAOYSA-M Y InChI=1S/C3H6OS2.K/c1-2-4-3(5)6;/h2H2,1H3,(H,5,6);/q;+1/p-1
Properties
Molecular formula	C3H5KOS2
Molar mass	160.30 g mol−1
Appearance	Pale yellow powder
Density	1.263 g/cm3[1]
Melting point	225 – 226 °C
Boiling point	decomposes
Acidity (pKa)	approximately 1.6
Hazards
R-phrases	R15 R21 R22 R29 R36 R38
S-phrases	S3 S9 S35 S36 S37 S38 S39 S16 S23 S51
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

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:^[2]

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.^[3] 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.^[4]

Safety

The LD50 is 683 mg/kg (oral, rats) for potassium ethyl xanthate.^[3]

References