potassium ethyl xanthate
{{chembox
| Watchedfields = changed
| verifiedrevid = 444062584
| Name = Potassium ethyl xanthate
| ImageFile = Potassium_ethyl_xanthate.png
| ImageSize =
| ImageName =
| ImageFile1 = Potassium ethyl xanthate 3D ball.png
| ImageAlt1 = Ball-and-stick model of the component ions of potassium ethyl xanthate
| PIN = Potassium O-ethylcarbonodithioate
| OtherNames = {{ubl|Potassium ethylxanthogenate|Potassium ethylxanthate|Potassium-O-ethyl dithiocarbonate}}
|Section1={{Chembox Identifiers
| CASNo = 140-89-6
| CASNo_Ref = {{cascite|correct|CAS}}
| ChEMBL = 2380738
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 8491
| EC_number = 205-439-3
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 1A6K3Y576K
| MeSHName =
| PubChem = 2735045
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C3H6OS2.K/c1-2-4-3(5)6;/h2H2,1H3,(H,5,6);/q;+1/p-1
| SMILES = [K+].[S-]C(=S)OCC
| InChI = 1S/C3H6OS2.K/c1-2-4-3(5)6;/h2H2,1H3,(H,5,6);/q;+1/p-1
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = JCBJVAJGLKENNC-UHFFFAOYSA-M
}}
|Section2={{Chembox Properties
| Formula = {{chem2|CH3CH2OCS2K}}
| C=3 | H=5 | O=1 | S=2 | K=1
| Appearance = Pale yellow powder
| Density = 1.263 g/cm3Report 5 (1995) p. 5
| MeltingPtC = 225 to 226
| MeltingPt_notes =
| BoilingPt = decomposes
| Solubility =
| pKa = approximately 1.6
| pKb = }}
|Section7={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
| GHSPictograms = {{GHS02}}{{GHS07}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|228|302|315|319|332|335}}
| PPhrases = {{P-phrases|210|240|241|261|264|270|271|280|301+312|302+352|304+312|304+340|305+351+338|312|321|330|332+313|337+313|362|370+378|403+233|405|501}}
}}
|Section9 = {{Chembox Related
| OtherAnions =
| OtherCations = Sodium ethyl xanthate
| OtherFunction =
| OtherCompounds =
}}
}}
Potassium ethyl xanthate (KEX) is an organosulfur compound with the chemical formula {{chem2|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. 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:This report gives a detailed recipe for potassium ethyl xanthate: {{OrgSynth|author=Charles C. Price, Gardner W. Stacy|year=1948|title=p-Nitrophenyl) Sulfide
| volume =28|pages=82|doi=10.15227/orgsyn.028.0082
}}
:{{chem2|CH3CH2OH + CS2 + KOH → CH3CH2OCS2K + H2O}}
The salt {{chem2|KS2COC5H11}}, 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.{{cite journal |author=N. A. Frolova, T. I. Malinovskii, V. Kh. Kravtsov, Yu. M. Chumakov, S. B. Leonov |year=1991 |title=КРИСТАЛЛИЧЕСКАЯ И МОЛЕКУЛЯРНАЯ СТРУКТУРА АМИЛКСАНТОГЕНАТА КАЛИЯ |trans-title=Crystal and Molecular Structure of Potassium Amylxanthate |url=https://www.mathnet.ru/eng/dan/v316/i2/p371 |journal=Dokl.Akad.Nauk SSSR (Proc.Nat.Acad.Sci.USSR) |language=ru |volume=316 |issue=2 |page=371}}
Potassium ethyl xanthate is a pale yellow powder that is stable at high pH, but rapidly hydrolyses below pH = 9:
:{{chem2|CH3CH2OCS2K + H+ → CH3CH2OH + CS2 + K+}}
Oxidation of xanthate salts gives diethyl dixanthogen disulfide:
:{{chem2|4 CH3CH2OCS2K + 2 H2O + O2 → 2 (CH3CH2OCS2)2 + 4 KOH}}
KEX is a source of ethylxanthate coordination complexes. For example, the octahedral complexes {{chem2|(CH3CH2OCS2)3Cr}}, {{chem2|(CH3CH2OCS2)3In}}, and {{chem2|(CH3CH2OCS2)3Co}} have been prepared from KEX.{{cite journal |doi=10.1002/9780470132418.ch6|title=Tris (O-Ethyldithiocarbonato) Complexes of Tripositive Chromium, Indium, and Cobalt |journal=Inorganic Syntheses |year=1967 |volume=10|last1=Galsbøl |first1=F. |last2=Schäffer |first2=C. E. |page=42}}
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.One of several procedures using xanthate esters: {{OrgSynth|author=Fabien Gagosz, Samir Z. Zard|year=1948|title=A Xanthate-Transfer Approach to α-Trifluoromethylamines |volume=84|page=32|doi=10.15227/orgsyn.084.0032}}
Safety
The LD50 is 103 mg/kg (oral, rats) for potassium ethyl xanthate.{{cite encyclopedia|author=Kathrin-Maria Roy|title=Xanthates|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|year=2005|publisher= Wiley-VCH|location=Weinheim|doi=10.1002/14356007.a28_423|isbn=3527306730}}