Potassium ethyl xanthate (KEX) is an
organosulfur compound
Organosulfur compounds are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature abounds with organosulfur compounds—sulfu ...
with the chemical formula CH
3CH
2OCS
2K. 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 containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 Apr ...
s. Unlike the related
sodium ethyl xanthate, the potassium salt exists as an
anhydrous
A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...
salt.
Production and properties
Xanthate
150px, Sodium salt of ethyl xanthate
Xanthate usually refers to a salt with the formula (R = alkyl; M+ = Na+, K+), thus they are the metal-thioate/''O''-esters of dithiocarbonate. The name ''xanthates'' is derived from Ancient Greek ''xanthos' ...
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 organic substituent. Alkoxides are strong bases and, whe ...
s on
carbon disulfide
Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non ...
. The alkoxide is often generated in situ from potassium hydroxide:
:EtOH + CS
2 + KOH → EtOCS
2K + H
2O
Potassium ethyl xanthate is a pale yellow powder that is stable at high pH but rapidly hydrolyses below pH <9:
:
Oxidation gives
diethyl dixanthogen disulfide:
:
KEX is a source of ethylxanthate
coordination complex
A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many ...
es. For example have been prepared from KEX for M = Cr, In, Co.
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 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 special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
.[One of several procedures using xanthate esters: ]
Safety
The is 103 mg/kg (oral, rats) for potassium ethyl xanthate.
References
{{reflist
Potassium compounds
Thiocarbonyl compounds
Metallurgical processes