Potassium ethyl xanthate

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Potassium ethyl xanthate
Potassium ethyl xanthate.png
Identifiers
CAS number 140-89-6 YesY
PubChem 2735045
ChemSpider 8491 YesY
Jmol-3D images Image 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
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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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[edit]

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[edit]

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[edit]

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

References[edit]

  1. ^ Report 5 (1995) p. 5
  2. ^ This report gives a detailed procedure Charles C. Price and Gardner W. Stacy (1948), p-nitrophenyl) sulfide, Org. Synth. 28: 82 ; Coll. Vol. 3: 667 
  3. ^ a b Kathrin-Maria Roy "Xanthates" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a28 423
  4. ^ One of several procedures using xanthate esters: Fabien Gagosz and Samir Z. Zard (1948), A Xanthate-Transfer Approach to α-Trifluoromethylamines, Org. Synth. 84: 32 ; Coll. Vol. 11: 212