Potassium ethyl xanthate

Potassium ethyl xanthate
Ball-and-stick model of the component ions of potassium ethyl xanthate
Names
Preferred IUPAC name
Potassium O-ethylcarbonodithioate
Other names
  • Potassium ethylxanthogenate
  • Potassium ethylxanthate
  • Potassium-O-ethyl dithiocarbonate
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.004.946 Edit this at Wikidata
EC Number
  • 205-439-3
UNII
  • InChI=1S/C3H6OS2.K/c1-2-4-3(5)6;/h2H2,1H3,(H,5,6);/q;+1/p-1 checkY
    Key: JCBJVAJGLKENNC-UHFFFAOYSA-M checkY
  • InChI=1S/C3H6OS2.K/c1-2-4-3(5)6;/h2H2,1H3,(H,5,6);/q;+1/p-1
  • [K+].[S-]C(=S)OCC
Properties
CH3CH2OCS2K
Molar mass 160.29 g·mol−1
Appearance Pale yellow powder
Density 1.263 g/cm3[1]
Melting point 225 to 226 °C (437 to 439 °F; 498 to 499 K)
Boiling point decomposes
Acidity (pKa) approximately 1.6
Hazards
GHS labelling:
GHS02: FlammableGHS07: Exclamation mark
Warning
H228, H302, H315, H319, H332, H335
P210, P240, P241, P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P370+P378, P403+P233, P405, P501
Related compounds
Other cations
 Sodium ethyl xanthate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Potassium ethyl xanthate (KEX) 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. It is a potassium salt of ethyl xanthic acid.

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:[2]

CH3CH2OH + CS2 + KOH → CH3CH2OCS2K + H2O

Potassium ethyl xanthate is a pale yellow powder that is stable at high pH, but rapidly hydrolyses below pH = 9:

CH3CH2OCS2K + H+ → CH3CH2OH + CS2 + K+

Oxidation gives diethyl dixanthogen disulfide:

4 CH3CH2OCS2K + 2 H2O + O2 → 2 (CH3CH2OCS2)2 + 4 KOH

KEX is a source of ethylxanthate coordination complexes. For example (CH3CH2OCS2)3M have been prepared from KEX for M = Cr, In, Co.[clarification needed][3]

Applications

Potassium ethyl xanthate is used in the mining industry as flotation agent for extraction of the ores of copper, nickel, and silver.[4] 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 esters are useful intermediates in organic synthesis.[5]

Safety

The LD50 is 103 mg/kg (oral, rats) for potassium ethyl xanthate.[4]

References

  1. ^ Report 5 (1995) p. 5
  2. ^ This report gives a detailed recipe for potassium ethyl xanthate: Charles C. Price, Gardner W. Stacy (1948). "p-Nitrophenyl) Sulfide". Organic Syntheses. 28: 82. doi:10.15227/orgsyn.028.0082.
  3. ^ Galsbøl, F.; Schäffer, C. E. (1967). "Tris ( O -Ethyldithiocarbonato) Complexes of Tripositive Chromium, Indium, and Cobalt". Tris (O-Ethyldithiocarbonato) Complexes of Tripositive Chromium, Indium, and Cobalt. Inorganic Syntheses. Vol. 10. pp. 42–49. doi:10.1002/9780470132418.ch6. ISBN 978-0-470-13169-5.
  4. ^ a b Kathrin-Maria Roy (2005). "Xanthates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a28_423. ISBN 3527306730.
  5. ^ One of several procedures using xanthate esters: Fabien Gagosz and Samir Z. Zard (1948). "A Xanthate-Transfer Approach to α-Trifluoromethylamines". Organic Syntheses. 84: 32; Collected Volumes, vol. 11, p. 212.