| |||
| Names | |||
|---|---|---|---|
| Preferred IUPAC name Benzenethiol[1] | |||
Other names
| |||
| Identifiers | |||
| |||
3D model (JSmol) | |||
| 506523 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider |
| ||
| ECHA InfoCard | 100.003.306 | ||
| EC Number |
| ||
| RTECS number |
| ||
| UNII | |||
| |||
| |||
| Properties | |||
| C6H6S | |||
| Molar mass | 110.17 g·mol−1 | ||
| Appearance | Colorless liquid | ||
| Odor | Unpleasant, pungent | ||
| Density | 1.0766 g/mL | ||
| Melting point | −15 °C (5 °F; 258 K) | ||
| Boiling point | 169 °C (336 °F; 442 K) | ||
| 0.08%[2] | |||
| Solubility | Most organic solvents; aqueous base | ||
| Vapor pressure | 1 mmHg (18°C)[2] | ||
| Acidity (pKa) | |||
| −70.8·10−6 cm3/mol | |||
| Hazards | |||
| Occupational safety and health (OHS/OSH): | |||
Main hazards | Toxic | ||
| GHS labelling: | |||
     | |||
| Danger | |||
| H226,H300,H310,H314,H315,H330,H410 | |||
| P210,P233,P240,P241,P242,P243,P260,P262,P264,P270,P271,P273,P280,P284,P301+P310,P301+P330+P331,P302+P350,P302+P352,P303+P361+P353,P304+P340,P305+P351+P338,P310,P312,P320,P321,P322,P330,P332+P313,P361,P362,P363,P370+P378,P391,P403+P233,P403+P235,P405,P501 | |||
| NFPA 704 (fire diamond) | |||
| Flash point | 56 °C; 132 °F; 329 K[2] | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible) | none[2] | ||
REL (Recommended) | C 0.1 ppm (0.5 mg/m3) [15-minute][2] | ||
IDLH (Immediate danger) | N.D.[2] | ||
| Related compounds | |||
Relatedthiols | 1,2-Benzenedithiol Benzenemethanethiol | ||
Related compounds | Phenol Benzeneselenol Diphenyl disulfide | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Thiophenol is anorganosulfur compound with the formula C6H5SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplestaromaticthiol. Thechemical structures of thiophenol and itsderivatives are analogous tophenols, where theoxygenatom in thehydroxyl group (−OH) bonded to the aromatic ring in phenol is replaced by asulfur atom. The prefixthio- implies a sulfur-containing compound and when used before a root word name for a compound which would normally contain an oxygen atom, in the case of 'thiol' that the alcohol oxygen atom is replaced by a sulfur atom.
Thiophenols also describes a class of compounds formally derived from thiophenol itself. All have asulfhydryl group (-SH)covalently bonded to an aromatic ring. The organosulfur ligand in the medicinethiomersal is a thiophenol.
There are several methods of synthesis for thiophenol and related compounds, although thiophenol itself is usually purchased for laboratory operations. 2 methods are the reduction ofbenzenesulfonyl chloride withzinc[5] and the action of elemental sulfur onphenyl magnesium halide orphenyllithium followed by acidification.
Via theNewman–Kwart rearrangement, phenols (1) can be converted to the thiophenols (5) by conversion to the O-aryl dialkylthiocarbamates (3), followed by heating to give the isomericS-aryl derivative (4).[6]
In theLeuckart thiophenol reaction, the starting material is ananiline through thediazonium salt (ArN2X) and thexanthate (ArS(C=S)OR).[7][8] Alternatively,sodium sulfide andtriazenes can react in organic solutions and yield thiophenols.[9]
Thiophenol can be manufactured fromchlorobenzene andhydrogen sulfide over alumina at 700 to 1,300 °F (371 to 704 °C). Thedisulfide is the primary byproduct.[10] The reaction medium is corrosive and requires ceramic or similar reactor lining. Aryl iodides andsulfur in certain conditions may also produce thiophenols.[11]
Thiophenols are used in the production ofpharmaceuticals including ofsulfonamides. The antifungal agentsbutoconazole andmerthiolate are derivatives of thiophenols.[9]
Thiophenol has appreciably greateracidity than does phenol, as is shown by theirpKa values (6.62 for thiophenol and 9.95 for phenol). A similar pattern is seen forH2S versus H2O, and allthiols versus the correspondingalcohols. Treatment of PhSH with strong base such assodium hydroxide (NaOH) orsodium metal affords the salt sodium thiophenolate (PhSNa).
The thiophenolate is highly nucleophilic, which translates to a high rate of alkylation.[12] Thus, treatment of C6H5SH withmethyl iodide in the presence of a base gives methyl phenyl sulfide, C6H5SCH3, athioether often referred to asthioanisole. Such reactions are fairly irreversible. C6H5SH also adds to α,β-unsaturated carbonyls viaMichael addition.
Thiophenols, especially in the presence of base are easily oxidized todiphenyl disulfide:
The 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.
Phenylsulfenyl chloride, a blood-red liquid (b.p. 41–42 °C, 1.5 mm Hg), can be prepared by the reaction of thiophenol withchlorine (Cl2).[13]
Metal cations form thiophenolates, some of which are polymeric. One example is "C6H5SCu," obtained by treatingcopper(I) chloride with thiophenol.[14]
The USNational Institute for Occupational Safety and Health has established arecommended exposure limit at a ceiling of 0.1 ppm (0.5 mg m−3), and exposures not greater than 15 minutes.[15]
{{cite journal}}: CS1 maint: multiple names: authors list (link);Collected Volumes, vol. 1, p. 504..{{cite journal}}: CS1 maint: multiple names: authors list (link){{cite journal}}: CS1 maint: multiple names: authors list (link);Collected Volumes, vol. 8, p. 550.{{cite journal}}: CS1 maint: multiple names: authors list (link);Collected Volumes, vol. 6, p. 248.| Authority control databases: National |
|---|