Ethanethiol
From Wikipedia, the free encyclopedia
| Ethanethiol | |
|---|---|
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| Chemical name | Ethanethiol |
| Other names | Ethyl mercaptan |
| Chemical formula | C2H6S |
| Molecular mass | 62.13404 g·mol−1 |
| CAS number | [75-08-1] |
| Density | 0.8617 g·cm−3 |
| Melting point | -148 °C |
| Boiling point | 35 °C |
| SMILES | CCS |
| MSDS | External MSDS |
| Main hazards | Nauseating |
| NFPA 704 | |
| R/S statement | R: 11-20-50/53 S: 16-25-60-61 |
| RTECS number | KI9625000 |
| Related compounds | |
| Related compounds | Methanethiol Ethanol thiophenol |
| Disclaimer and references | |
Ethanethiol is the organic compound with the formula CH3CH2SH. It consists of an ethyl group, CH3CH2, abbreviated Et, attached to a thiol group, SH, and the entire molecule is often abbreviated EtSH. The compound is structurally similar to ethanol by replacement of O by S. This change leads to many different properties, the most infamous of which is the strong odour of EtSH. Ethanethiol is also more volatile than ethanol due to its diminished ability to engage in hydrogen bonding. Ethanethiol occurs naturally as a minor component of petroleum distillates.
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[edit] Odor
Ethanethiol has strongly disagreeable odour that humans can detect in minute concentrations. The threshold for human detection is as low as one part in 2.8 billion parts of air. Its odour resembles that of leeks. Ethanethiol is intentionally added to butane and propane (see: LPG) to impart an easily noticed smell to these odourless fuels, that otherwise pose the threat of asphyxiation.
According to the 2000 edition of the Guinness Book Of World Records, ethanethiol is the "smelliest substance" in existence. Other more specialized chemicals were probably not examined, however. Most volatile thiols are comparably offensive. Thiols can be oxidized, and thus de-odourized, using bleach or related oxidants.
[edit] Reactions
Ethanethiol is a valued reagent in organic synthesis. In the presence of sodium hydroxide, it forms the powerful nucleophile NaSEt.[1] Oxidation of EtSH gives the disulfide, Diethyl Disulfide:
- 2 EtSH + H2O2 → EtS-SEt + 2 H2O
Like other thiols, it behaves comparably to hydrogen sulfide. For example, it binds to "soft" transition metals cations, such a Hg2+, Cu+, and Ni2+.
[edit] Safety
Ethanethiol is toxic (see MSDS) although the amount added to LPG is non-threatening.
[edit] References
- ^ procedure for generating NaSEt: Mirrington, R. N.; Feutrill, G. I. “Orcinol Monomethyl Ether” Organic Syntheses, Collected Volume 6, p.859 (1988). http://www.orgsyn.org/orgsyn/pdfs/CV6P0859.pdf
[edit] General reading
- Merck Index, 12th edition, 3771
