Potassium ethyl xanthate (KEX) is an

organosulfur compound Organosulfur chemistry is the study of the properties and synthesis of organosulfur compounds, which are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur der ...

with the chemical formula . It is a pale yellow powder that is used in the mining industry for the separation of

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically including metals, concentrated above background levels, and that is economically viable to mine and process. The grade of ore refers to the concentration ...

s. It is a

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

salt of ethyl xanthic acid. Many

xanthate A xanthate is a Salt (chemistry), salt or ester of a xanthic acid. The formula of the salt of xanthic acid is (where R is organyl group and M is usually Sodium, Na or Potassium, K). Xanthate also refers to the anion . The formula of a xanthic a ...

s are known.

Production and properties

Xanthate A xanthate is a Salt (chemistry), salt or ester of a xanthic acid. The formula of the salt of xanthic acid is (where R is organyl group and M is usually Sodium, Na or Potassium, K). Xanthate also refers to the anion . The formula of a xanthic a ...

salts are prepared by the action of

alkoxide In chemistry, an alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They are written as , where R is the organyl substituent. Alkoxides are strong bases and, whe ...

s on

carbon disulfide Carbon disulfide (also spelled as carbon disulphide) is an inorganic compound with the chemical formula and structure . It is also considered as the anhydride of thiocarbonic acid. It is a colorless, flammable, neurotoxic liquid that is used as ...

. 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 X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to Diffraction, diffract in specific directions. By measuring th ...

. 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 Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

below pH = 9: : Oxidation of xanthate salts gives diethyl dixanthogen disulfide: : KEX is a source of ethylxanthate

coordination complex A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...

es. For example, the

octahedral In geometry, an octahedron (: octahedra or octahedrons) is any polyhedron with eight faces. One special case is the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at each vertex. Many types of i ...

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 In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

for preparing xanthate esters from alkyl and aryl halides. The resulting xanthate esters are useful intermediates in

organic synthesis Organic synthesis is a branch of chemical synthesis concerned with the construction of organic compounds. Organic compounds are molecules consisting of combinations of covalently-linked hydrogen, carbon, oxygen, and nitrogen atoms. Within the gen ...

.One of several procedures using xanthate esters:

Safety

The LD₅₀ is 103 mg/kg (oral,

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...

s) for potassium ethyl xanthate.

References

{{reflist Potassium compounds Thiocarbonyl compounds Metallurgical processes