Potassium thioacetate 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 ...
and a
salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...
with the formula . This white, water-soluble solid is used as a
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 thioacetate
ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...
s and other derivatives.
Synthesis and reactions
Potassium thioacetate, which is commercially available, can be prepared by combining
acetyl chloride
Acetyl chloride (CH3COCl) is an acyl chloride derived from acetic acid. It belongs to the class of organic compounds called acid halides. It is a colorless, corrosive, volatile liquid. Its formula is commonly abbreviated to AcCl.
Synthesis
On a ...
and
potassium hydrogen sulfide:
:
CH3COCl + 2 KSH -> KCl + CH3COSK + H2S
It arises also by the neutralization of
thioacetic acid
Thioacetic acid is an organosulfur compound with the molecular formula . It is the sulfur analogue of acetic acid (), as implied by the ''thio-'' prefix. It is a yellow liquid with a strong thiol-like odor. It is used in organic synthesis for the ...
with
potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash.
Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...
.
Use in preparation of thiols
In a common application, potassium thioacetate is combined with
alkylating agent
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting al ...
s to give
thioacetate esters (X =
halide
In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a fluor ...
):
:
CH3COSK + RX -> CH3COSR + KX
Hydrolysis of these esters affords
thiol
In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...
s:
:
CH3COSR + H2O -> CH3CO2H + RSH
The thioacetate esters can also be cleaved with methanethiol in the presence of stoichiometric base, as illustrated in the preparation of pent-4-yne-1-thiol:
[{{cite journal, title=4-Pentyne-1-thiol, authors=Matteo Minozzi, Daniele Nanni, Piero Spagnolo, year=2008, doi=10.1002/047084289X.rn00855, journal=EEROS, isbn=978-0471936237 ]
:
H3C(CH2)3OMs + KSAc -> H3C(CH2)3SAc + KOMs
:
H3C(CH2)3SAc + HSMe -> H3C(CH2)3SH + MeSAc
References
Reagents for organic chemistry
Organosulfur compounds
Potassium compounds