Ethanethiol

Last updated
Ethanethiol [1] [2]
Ethanethiol-skeletal.svg
Ethanethiol-3D-balls.png
Names
Preferred IUPAC name
Ethanethiol
Other names
Ethyl mercaptan
Mercaptoethane
Ethyl sulfhydrate
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.000.762 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 200-837-3
PubChem CID
RTECS number
  • KI9625000
UNII
UN number 2363
  • InChI=1S/C2H6S/c1-2-3/h3H,2H2,1H3 Yes check.svgY
    Key: DNJIEGIFACGWOD-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C2H6S/c1-2-3/h3H,2H2,1H3
    Key: DNJIEGIFACGWOD-UHFFFAOYAW
  • CCS
Properties
C2H6S
Molar mass 62.13404 g·mol−1
AppearanceColorless 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:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg GHS-pictogram-pollu.svg
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)
NFPA 704.svgHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
4
0
Flash point −48 °C; −55 °F; 225 K [3]
Explosive limits 2.8–18.0% [3]
Lethal dose or concentration (LD, LC):
682 mg/kg (rat, oral) [4]
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 their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Ethanethiol, commonly known as ethyl mercaptan, is an organosulfur compound with the formula CH3CH2SH. [5] is a colorless liquid with a distinct odor. Abbreviated EtSH, it consists of an ethyl group (Et), CH3CH2, attached to a thiol group, SH. Its structure parallels that of ethanol, but with sulfur in place of oxygen. The odor of EtSH is infamous. Ethanethiol is more volatile than ethanol due to a diminished ability to engage in hydrogen bonding. Ethanethiol is toxic in high concentrations. It occurs naturally as a minor component of petroleum, and may be added to otherwise odorless gaseous products such as liquefied petroleum gas (LPG) to help warn of gas leaks. At these concentrations, ethanethiol is not harmful.

Contents

Preparation

Ethanethiol is prepared by the reaction of ethylene with hydrogen sulfide in the presence of various catalysts. It is also prepared commercially by the reaction of ethanol with hydrogen sulfide gas over an acidic solid catalyst, such as alumina. [6]

Historic methods

Ethanethiol was originally reported by Zeise in 1834. [7] Zeise treated calcium ethyl sulfate with a suspension of barium sulfide saturated with hydrogen sulfide. He is credited with naming the C2H5S- group as mercaptum.

Ethanethiol can also be prepared by a halide displacement reaction, where ethyl halide is treated with aqueous sodium bisulfide. This conversion was demonstrated as early as 1840 by Henri Victor Regnault. [8]

Odor

Ethanethiol has a strongly disagreeable odor 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 (0.36 parts per billion). Its odor resembles that of leeks, onions, durian or cooked cabbage. [9]

Employees of the Union Oil Company of California reported first in 1938 that turkey 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]

Uses

Ethanethiol is intentionally added to butane and propane (see: LPG) to impart an easily noticed smell to these normally odorless fuels that pose the threat of fire, explosion, and asphyxiation.

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. In Ontario, 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]

Reactions

Ethanethiol is a reagent in organic synthesis. In the presence of sodium hydroxide, it gives the powerful nucleophile EtS−. The salt can be generated quantitatively by reaction with sodium hydride. [14]

Ethanethiol can be oxidized to ethyl sulfonic acid, using strong oxidizing agents. Weaker oxidants, such as ferric oxide or hydrogen peroxide give the disulfide, diethyl disulfide:

2 EtSH + H2O2 → EtS-SEt + 2 H2O

Like other thiols, it behaves comparably to hydrogen sulfide. For example, it binds, concomitant with deprotonation to "soft" transition metal cations, such as Hg2+, Cu+, and Ni2+ to give polymeric thiolato complexes, Hg(SEt)2, CuSEt, and Ni(SEt)2, respectively.

See also

Related Research Articles

<span class="mw-page-title-main">Ethanol</span> Organic compound (CH₃CH₂OH)

Ethanol is an organic compound with the chemical formula CH3CH2OH. It is an alcohol, with its formula also written as C2H5OH, C2H6O or EtOH, where Et stands for ethyl. Ethanol is a volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. It is a psychoactive recreational drug, and the active ingredient in alcoholic drinks.

<span class="mw-page-title-main">Thiol</span> Any organic compound having a sulfanyl group (–SH)

In organic chemistry, a thiol, or thiol derivative, is any organosulfur compound of the form R−SH, where R represents an alkyl or other organic substituent. The −SH functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols, and the word is a blend of "thio-" with "alcohol".

<span class="mw-page-title-main">Hydrogen sulfide</span> Poisonous, corrosive and flammable gas

Hydrogen sulfide is a chemical compound with the formula H2S. It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The underground mine gas term for foul-smelling hydrogen sulfide-rich gas mixtures is stinkdamp. Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777. The British English spelling of this compound is hydrogen sulphide, a spelling no longer recommended by the Royal Society of Chemistry or the International Union of Pure and Applied Chemistry.

<span class="mw-page-title-main">Methanethiol</span> Chemical compound

Methanethiol is an organosulfur compound with the chemical formula CH
3SH. It is a colorless gas with a distinctive putrid smell. It is a natural substance found in the blood, brain and feces of animals, as well as in plant tissues. It also occurs naturally in certain foods, such as some nuts and cheese. It is one of the chemical compounds responsible for bad breath and the smell of flatus. Methanethiol is the simplest thiol and is sometimes abbreviated as MeSH. It is very flammable.

<span class="mw-page-title-main">Aroma compound</span> Chemical compound that has a smell or odor

An aroma compound, also known as an odorant, aroma, fragrance or flavoring, is a chemical compound that has a smell or odor. For an individual chemical or class of chemical compounds to impart a smell or fragrance, it must be sufficiently volatile for transmission via the air to the olfactory system in the upper part of the nose. As examples, various fragrant fruits have diverse aroma compounds, particularly strawberries which are commercially cultivated to have appealing aromas, and contain several hundred aroma compounds.

<span class="mw-page-title-main">Ethyl acetate</span> Organic compound (CH₃CO₂CH₂CH₃)

Ethyl acetate is the organic compound with the formula CH3CO2CH2CH3, simplified to C4H8O2. This colorless liquid has a characteristic sweet smell and is used in glues, nail polish removers, and in the decaffeination process of tea and coffee. Ethyl acetate is the ester of ethanol and acetic acid; it is manufactured on a large scale for use as a solvent.

<span class="mw-page-title-main">Diisopropyl ether</span> Chemical compound

Diisopropyl ether is a secondary ether that is used as a solvent. It is a colorless liquid that is slightly soluble in water, but miscible with organic solvents. It is used as an extractant and an oxygenate gasoline additive. It is obtained industrially as a byproduct in the production of isopropanol by hydration of propylene. Diisopropyl ether is sometimes represented by the abbreviation DIPE.

<i>tert</i>-Butyl alcohol Chemical compound

tert-Butyl alcohol is the simplest tertiary alcohol, with a formula of (CH3)3COH (sometimes represented as t-BuOH). Its isomers are 1-butanol, isobutanol, and butan-2-ol. tert-Butyl alcohol is a colorless solid, which melts near room temperature and has a camphor-like odor. It is miscible with water, ethanol and diethyl ether.

<span class="mw-page-title-main">Thioglycolic acid</span> Chemical compound

Thioglycolic acid (TGA) is the organic compound HSCH2CO2H. TGA is often called mercaptoacetic acid (MAA). It contains both a thiol (mercaptan) and carboxylic acid functional groups. It is a colorless liquid with a strongly unpleasant odor. TGA is miscible with polar organic solvents.

<span class="mw-page-title-main">Diethyl sulfate</span> Chemical compound

Diethyl sulfate (DES) is a highly toxic, combustible, and likely carcinogenic chemical compound with the formula (C2H5)2SO4. It occurs as a colorless, oily liquid with a faint peppermint odor and is corrosive to tissue and metals. Diethyl sulfate is used as an alkylating agent to prepare ethyl derivatives of phenols, amines, and thiols. It is used to manufacture dyes and textiles.

Bromoethane, also known as ethyl bromide, is a chemical compound of the haloalkanes group. It is abbreviated by chemists as EtBr. This volatile compound has an ether-like odor.

<span class="mw-page-title-main">Sodium sulfide</span> Chemical compound

Sodium sulfide is a chemical compound with the formula Na2S, or more commonly its hydrate Na2S·9H2O. Both the anhydrous and the hydrated salts in pure crystalline form are colorless solids, although technical grades of sodium sulfide are generally yellow to brick red owing to the presence of polysulfides and commonly supplied as a crystalline mass, in flake form, or as a fused solid. They are water-soluble, giving strongly alkaline solutions. When exposed to moist air, Na2S and its hydrates emit hydrogen sulfide, an extremely toxic, flammable and corrosive gas which smells like rotten eggs.

<span class="mw-page-title-main">Thiophenol</span> Chemical compound

Thiophenol is an organosulfur compound with the formula C6H5SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplest aromatic thiol. The chemical structures of thiophenol and its derivatives are analogous to phenols. An exception is the oxygen atom in the hydroxyl group (-OH) bonded to the aromatic ring is replaced by a sulfur 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, in the case of 'thiol' that the alcohol oxygen atom is replaced by a sulfur atom.

<span class="mw-page-title-main">2-Ethoxyethanol</span> Chemical compound

2-Ethoxyethanol, also known by the trademark Cellosolve or ethyl cellosolve, is a solvent used widely in commercial and industrial applications. It is a clear, colorless, nearly odorless liquid that is miscible with water, ethanol, diethyl ether, acetone, and ethyl acetate.

Merox is an acronym for mercaptan oxidation. It is a proprietary catalytic chemical process developed by UOP used in oil refineries and natural gas processing plants to remove mercaptans from LPG, propane, butanes, light naphthas, kerosene and jet fuel by converting them to liquid hydrocarbon disulfides.

<span class="mw-page-title-main">1-Butanethiol</span> Chemical compound

1-Butanethiol, also known as butyl mercaptan, is a volatile, clear to yellowish liquid with a fetid odor, commonly described as "skunk" odor. In fact, 1-butanethiol is structurally similar to several major constituents of a skunk's defensive spray but is not actually present in the spray. The scent of 1-butanethiol is so strong that the human nose can easily detect it in the air at concentrations as low as 10 parts per billion. The threshold level for 1-butanethiol is reported as 1.4 ppb

The molecular formula C4H10S may refer to:

<i>tert</i>-Butylthiol Chemical compound

tert-Butylthiol, also known as 2-methylpropane-2-thiol, 2-methyl-2-propanethiol, tert-butyl mercaptan (TBM), and t-BuSH, is an organosulfur compound with the formula (CH3)3CSH. This thiol is used as an odorant for natural gas, which is otherwise odorless. It may also have been used as a flavoring agent.

<span class="mw-page-title-main">Propanethiol</span> Chemical compound

Propanethiol is an organic compound with the molecular formula C3H8S. It belongs to the group of thiols. It is a colorless liquid with a strong, offensive odor. It is moderately toxic and is less dense than water and slightly soluble in water. It is used as a feedstock for insecticides. It is highly flammable and it gives off irritating or toxic fumes (or gases) in a fire. Heating it will cause rise in pressure with risk of bursting.

<span class="mw-page-title-main">Cyclohexanethiol</span> Chemical compound

Cyclohexanethiol is a thiol with the formula C6H11SH. It is a colorless liquid with a strong odor.

References

  1. ↑ Merck Index, 12th edition, hEllon and 3771
  2. ↑ "ICSC 0470 - ETHANETHIOL".
  3. 1 2 3 4 5 6 7 8 9 NIOSH Pocket Guide to Chemical Hazards. "#0280". National Institute for Occupational Safety and Health (NIOSH).
  4. 1 2 "Ethyl mercaptan". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  5. ↑ Staley, Dennis; Wilbraham, Antony; Matta, Michael; Waterman, Edward (2017). Pearson Chemistry. United States: Pearson Education, Inc. pp. R25. ISBN   978-1-32-320590-7.
  6. ↑ Norell, John; Louthan, Rector P. (1988). "Thiols". Kirk-Othmer Concise Encyclopedia of Chemical Technology (3rd ed.). New York: John Wiley & Sons, Inc. pp. 946–963. ISBN   978-0471801047.
  7. ↑ Zeise, William Christopher (1834). "Sur le Mercaptan; avec des Observations sur d'autres produits resultant de l'action des sulfovinates ainsi que de l'huile de vin, sur des sulfures metalliques" [On mercaptan; with comments on other products resulting from the action of [salts of] ethyl hydrogen sulfate as well as oil of wine [diethyl sulfate] on metallic sulfides]. Annales de Chimie et de Physique. 2nd series (in French). 56: 87–97.
  8. ↑ Regnault, V (1840). "Ueber die Einwirkung des Chlors auf die Chlorwasserstoffäther des Alkohols und Holzgeistes und über mehrere Punkte der Aethertheorie" [On the effect of chlorine on the volatile hydrochlorides of ethanol and methanol and on several points of ether theory]. Annalen der Chemie und Pharmacie (in German). 34: 24–52. doi:10.1002/jlac.18400340103. From p. 24: "Das Aethylsulfür war bis jetzt noch nicht dargestellt worden. Man erhält es sehr leicht durch wechselseitige Zersetzung, wenn man Aethylchlorür mit einer weingeistigen Auflösung von einfach Schwefelkalium zusammenbringt." (Ethanethiol still has not been prepared – until now. One obtains it very easily by reciprocal decomposition [i.e., salt metathesis reaction ], if one brings together ethyl chloride with a solution, in ethanol, of simple potassium hydrogen sulfide.)
  9. ↑ "Ethanethiol price,buy Ethanethiol - chemicalbook". www.chemicalbook.com. Retrieved 16 November 2019.
  10. ↑ Gooley, Tristan (21 May 2015). The Walker's Guide to Outdoor Signs. Sceptre. p. 242. ISBN   9781444780109.
  11. ↑ Nicholls, Henry. "The truth about vultures" . Retrieved 2016-10-21.
  12. ↑ "Stench Gas". Zacon Ltd. Archived from the original on 3 April 2015. Retrieved 20 February 2015.
  13. ↑ "Occupational Health and Safety Act: R.R.O. 1990, REGULATION 854 MINES AND MINING PLANTS Sect. 26(6)(a)". Ontario Ministry of Labour. Retrieved 20 February 2015.
  14. ↑ Mirrington, R. N.; Feutrill, G. I. (1988). "Orcinol Monomethyl Ether". Organic Syntheses .; Collective Volume, vol. 6, p. 859
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