- Thiophenol
Chembox new
ImageFile = Thiophenol.png
ImageSize =
IUPACName = Thiophenol
OtherNames = Benzenethiol
Section1 = Chembox Identifiers
CASNo = 108-98-5
PubChem =
SMILES = c1ccccc1S
RTECS = DC0525000
Section2 = Chembox Properties
Formula = C6H6S
MolarMass = 110.19 g/mol
Appearance = colorless liquid
Density = 1.0766 g/mL
MeltingPt = -15 °C
BoilingPt = 169 °C
Solubility =
SolubileOther = Most organic solvents; aqueous base
Section3 = Chembox Hazards
MainHazards = Toxic
FlashPt =
Autoignition =
RPhrases = R10 R24/25 R26 R41
SPhrases = S23 S26 S28 S36/37/39 S45Thiophenol is a
chemical compound with the formula C6H5SH, and sometimes abbreviated as PhSH. The foul-smelling liquid is the principalaromatic thiol . Thechemical structure s of thiophenols are analogous tophenols except theoxygen atom in thehydroxyl group (-OH) bonded to the aromatic ring is replaced by asulfur atom. The prefix thio- implies a sulfur-containing compound and when used before a root word name for a compound which would normally contain an oxygen atom, "thio-" commonly means that the oxygen atom is replaced by a sulfur atom.Thiophenols also describes a class of compounds formally derived from thiophenol itself. All have a
sulfhydryl group (-SH) covalently bonded to an aromatic ring. The organosulfur ligand in medicinemerthiolate is a thiophenol.ynthesis
Many ways exist to generate thiophenol and related compounds, although thiophenol is usually purchased for laboratory operations.
*Reduction ofbenzenesulfonyl chloride withzinc . [OrgSynth | author = Adams, R.; C. S. Marvel, C. S. | title = Thiophenol | collvol = 1 | collvolpages = 504 | prep = cv1p0504]
*Action of elemental sulfur on phenyl magnesium halide orphenyllithium followed by acificiation.Properties
Acidity
Thiophenol has appreciably greater
acid ity than does phenol. A similar pattern is seen for H2S vs. H2O and allthiol s vs. the correspondingalcohol s. Treatment of PhSH with strong base such assodium hydroxide (NaOH) orsodium metal affords the salt sodium thiophenolate (PhSNa). Such salts are readily oxidized.Alkylation
The thiophenolate is highly nucleophilic, which translates to an high rate of alkylation. [Campopiano, O. "Thiophenol" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.] Thus, treatment of C6H5SH with
methyl iodide in the presence of a base gives methyl phenyl sulfide, C6H5SCH3, athioether . Such reactions are fairly irreversible. C6H5SH also adds to α,β-unsaturated carbonyls viaMichael addition .Oxidation
A substantial difference between sulfur and oxygen is that thiophenolate is oxidized to
diphenyl disulfide :: 2 C6H5SH + 1/2 O2 → C6H5S-SC6H5 + H2OThe disulfide can be reduced back the thiol usingsodium borohydride followed by acidification. This redox reaction is also exploited in the use of C6H5SH as a source of H atoms. Of course free H atoms are almost never observed in solution, but C6H5SH delivers the equivalent result by adding H atoms to various substrates.Chlorination
Phenylsulfenyl chloride, a blood-red liquid (b.p. 41–42 °C), can be prepared by the reaction of thiophenol with
chlorine (Cl2). [OrgSynth | author = Barrett, A. G. M.; Dhanak, D.; Graboski, G. G.; Taylor, S. J. | title = (Phenylthio)nitromethane | collvol = 8 | collvolpages = 550 | year = 1993 | prep = cv8p0550]Coordination to metals
Metal cations form thiophenolates, some of which are polymeric. One example is "C6H5SCu," obtained by treating
copper(I) chloride with thiophenol. [OrgSynth | author = Posner, G. H.; Whitten, C. E. | title = Secondary and Tertiary Alkyl Ketones from Carboxylic Acid Chlorides and Lithium Phenylthio(alkyl)cuprate Reagents: tert-Butyl Phenyl Ketone | collvol = 6 | collvolpages = 248 | prep = cv6p0248]afety
Thiophenol is highly toxic.
References
Wikimedia Foundation. 2010.