Diphenyl disulfide
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| Diphenyl disulfide | |
|---|---|
| Image:Diphenyl disulfide.png | |
| General | |
| Systematic name | Diphenyl disulfide |
| Other names | Phenyl disulfide |
| Molecular formula | C12H10S2 |
| SMILES | C1(SSC2=CC=CC=C2)=CC=CC=C1 |
| Molar mass | 218.36 g/mol |
| Appearance | Colourless crystals |
| CAS number | [882-33-7] |
| Properties | |
| Density and phase | ? g/cm3 |
| Solubility in water | Insoluble |
| Other solvents | Diethyl ether, Benzene, Carbon disulfide, THF |
| Melting point | 61–62 °C |
| Boiling point | ? °C |
| Structure | |
| Crystal structure | |
| Dipole moment | 0 D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Flammable |
| NFPA 704 | |
| Flash point | ? °C |
| R/S statement | R: 36/37/38 S: 26 |
| RTECS number | SS6825000 |
| Supplementary data page | |
| Structure and properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Related compounds | C6H5SH, (CH3)2S2, Diphenyl diselenide |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references | |
Diphenyl disulfide is the chemical compound with the formula [C6H5S]2. This colorless crystalline material is often abbreviated Ph2S2. It is one of the most popular organic disulfides used in organic synthesis.
Contents |
[edit] Preparation
Ph2S2 is usually prepared by the oxidation of thiophenol:
- 2 PhSH + I2 → Ph2S2 + 2 HI
Hydrogen peroxide can also be used as the oxidant.<ref>Ravikumar,K. S.; Kesavan, V.; Crousse, B.; Bonnet-Delpon, D.; Bégué, J.-P. “Mild and Selective Oxidation of Sulfur Compounds in Trifluoroethanol: Diphenyl Disulfide and Methyl Phenyl Sulfoxide” Organic Syntheses, Volume 80, p.184ff, (2003)</ref> Ph2S2 is rarely prepared in the laboratory because it is inexpensive, and the precursor has a disagreeable odour.
[edit] Reactions
Ph2S2 is mainly used in organic synthesis as a source of the PhS substituent.<ref>Byers, J. H. "Diphenyl Disulfide" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.</ref> A typical reaction entails the formation of PhS-substituted carbonyl compounds via the enolate:
- RC(O)CHLiR’ + Ph2S2 → RC(O)CH(SPh)R’ + LiSPh
[edit] Reduction
Ph2S2 undergoes reduction, a reaction characteristic of disulfides:
- Ph2S2 + 2 M → 2 MSPh (M = Li, Na, K)
Hydride reagents such as sodium borohydride and super hydride can also be used as reductants. The salts PhSM are sources of the potent nucleophile PhS-. Most alkyl halides, RX (X = halide) convert it to the thioethers with the general formula RSPh. Analogously, protonation of MSPh gives thiophenol:
- PhSM + HCl → HSPh + MCl
[edit] Chlorination
Ph2S2 reacts with chlorine to give the sulfenyl chloride PhSCl (Zincke disulfide cleavage). This species is difficult to isolate, so it is usually generated in situ.
[edit] Catalyst for photoisomerisation of alkenes
Ph2S2catalyzes the cis-trans isomerization of alkenes under UV-irradiation.<ref>Thalmann, A. Oertle, K.; Gerlach, H. “Ricinelaidic Acid Lactone” Organic Syntheses, Collected Volume 7, p.470ff (1990).</ref>
[edit] Oxidation
Oxidation of Ph2S2 with lead(IV) acetate (Pb(OAc)4) in methanol affords the sulfinite ester PhS(O)OMe.<ref>Field, L.; Locke, J. M. “Methyl Benzenesulfinate” Organic Syntheses, Collected Volume 5, p.723 (1973).</ref>
[edit] References
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