 | |
 | |
| Names | |
|---|---|
| Preferred IUPAC name Ethanethiol | |
| Other names Ethyl mercaptan Mercaptoethane Ethyl sulfhydrate | |
| Identifiers | |
| |
3D model (JSmol) | |
| ChEBI | |
| ChemSpider |
|
| ECHA InfoCard | 100.000.762 |
| EC Number |
|
| RTECS number |
|
| UNII | |
| UN number | 2363 |
| |
| |
| Properties | |
| C2H6S | |
| Molar mass | 62.13404 g·mol−1 |
| Appearance | Colorless liquid[3] |
| Odor | Rotten cabbage, flatulence, skunk-like[3] |
| Density | 0.8617 g·cm−3 |
| Melting point | −148 °C (−234 °F; 125 K) |
| Boiling point | 35 °C (95 °F; 308 K) |
| 0.7% (20 °C)[3] | |
| Vapor pressure | 442 mmHg (20 °C)[3] |
| Acidity (pKa) | 10.6 |
| −47.0×10−6 cm3/mol | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards | Nauseating |
| GHS labelling: | |
   | |
| Danger | |
| H225,H332,H410 | |
| P210,P233,P240,P241,P242,P243,P261,P271,P273,P280,P303+P361+P353,P304+P312,P304+P340,P312,P370+P378,P391,P403+P235,P501 | |
| NFPA 704 (fire diamond) | |
| Flash point | −48 °C; −55 °F; 225 K[3] |
| Explosive limits | 2.8–18.0%[3] |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 682 mg/kg (rat, oral)[4] |
LC50 (median concentration) | 4410 ppm (rat, 4 hr) 2770 (mouse, 4 hr)[4] |
| NIOSH (US health exposure limits): | |
PEL (Permissible) | C 10 ppm (25 mg/m3)[3] |
REL (Recommended) | C 0.5 ppm (1.3 mg/m3) [15-minute][3] |
IDLH (Immediate danger) | 500 ppm[3] |
| Related compounds | |
Related compounds | Methanethiol Butanethiol Ethanol thiophenol |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Ethanethiol, commonly known asethyl mercaptan, is anorganosulfur compound with the formula CH3CH2SH.[5] It is a colorless liquid with a distinct odor. Abbreviated EtSH, it consists of an ethyl group (Et), CH3CH2, attached to athiol group, SH. Its structure parallels that ofethanol, but withsulfur in place ofoxygen. The odor of EtSH is infamous. Ethanethiol is morevolatile than ethanol due to a diminished ability to engage inhydrogen bonding. Ethanethiol is toxic in high concentrations. It occurs naturally as a minor component ofpetroleum, and may be added to otherwise odorless gaseous products such asliquefied petroleum gas (LPG) to help warn of gas leaks. At these concentrations, ethanethiol is not harmful.
Ethanethiol is prepared by the reaction ofethylene withhydrogen sulfide in the presence of variouscatalysts. It is also prepared commercially by the reaction ofethanol withhydrogen sulfide gas over an acidic solid catalyst, such asalumina.[6]
Ethanethiol was originally reported byZeise in 1834.[7] Zeise treated calcium ethyl sulfate with a suspension ofbarium sulfide saturated with hydrogen sulfide. He is credited with naming the C2H5S- group as mercaptum.
Ethanethiol can also be prepared by ahalide displacement reaction, where ethyl halide is treated with aqueoussodium bisulfide. This conversion was demonstrated as early as 1840 byHenri Victor Regnault.[8]
Ethanethiol has a strongly disagreeableodor thathumans can detect in minute concentrations. The threshold for human detection is as low as one part in 2.8 billion parts of air (0.36 parts per billion). Its odor resembles that ofleeks,onions,durian or cookedcabbage.[9]
Employees of theUnion Oil Company of California reported first in 1938 thatturkey vultures would gather at the site of any gas leak. After finding that this was caused by traces of ethanethiol in the gas it was decided to boost the amount of ethanethiol in the gas, to make detection of leaks easier.[10][11]
Ethanethiol is intentionally added tobutane andpropane (see:LPG) to impart an easily noticed smell to these normally odorless fuels that pose the threat offire,explosion, andasphyxiation.
In the underground mining industry, ethanethiol or ethyl mercaptan is referred to as "stench gas".[12] The gas is released into mine ventilation systems during an emergency to alert mine workers. InOntario, mining legislation dictates that "The alarm system in an underground mine shall, consist of the introduction into all workplaces of sufficient quantities of ethyl mercaptan gas or similar gas to be readily detectable by all workers".[13]
Ethanethiol is areagent inorganic synthesis. In the presence ofsodium hydroxide, it gives the powerfulnucleophile EtS−. The salt can be generated quantitatively by reaction withsodium hydride.[14]
Ethanethiol can be oxidized to ethylsulfonic acid, using strongoxidizing agents. Weaker oxidants, such asferric oxide orhydrogen peroxide give thedisulfide, diethyl disulfide:
Like other thiols, it behaves comparably to hydrogen sulfide. For example, it binds, concomitant with deprotonation to "soft"transition metalcations, such as Hg2+, Cu+, and Ni2+ to give polymeric thiolato complexes, Hg(SEt)2, CuSEt, and Ni(SEt)2, respectively.
| Authority control databases: National |
|---|
