Ethanethiol

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.{{cite book |last1=Norell |first1=John |last2=Louthan |first2=Rector P. |title=Kirk-Othmer Concise Encyclopedia of Chemical Technology |edition=3rd |year=1988 |publisher= John Wiley & Sons, Inc.|location=New York|isbn=978-0471801047|pages=946–963 |chapter=Thiols}}

Ethanethiol was originally reported by Zeise in 1834.{{cite journal|last=Zeise|first=William Christopher|title=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 |trans-title=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 |journal=Annales de Chimie et de Physique |year=1834 |series=2nd series |volume=56 |pages=87–97 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hx3dwt;view=1up;seq=93 |language=fr}} 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.{{cite journal|last=Regnault|first=V|title=Ueber die Einwirkung des Chlors auf die Chlorwasserstoffäther des Alkohols und Holzgeistes und über mehrere Punkte der Aethertheorie |trans-title=On the effect of chlorine on the volatile hydrochlorides of ethanol and methanol and on several points of ether theory |journal= Annalen der Chemie und Pharmacie | year=1840 |volume=34 |pages=24–52 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hx3bgj;view=1up;seq=418 |doi=10.1002/jlac.18400340103 |language=de}} 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.)

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.{{cite web |title=Ethanethiol price,buy Ethanethiol - chemicalbook |url=https://www.chemicalbook.com/Price/Ethanethiol.htm#Properties |website=www.chemicalbook.com |access-date=16 November 2019}}

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.{{Cite book|title=The Walker's Guide to Outdoor Signs|last=Gooley|first=Tristan|author-link=Tristan Gooley|date=21 May 2015|publisher=Sceptre|isbn=9781444780109|pages=242}}{{Cite web|url=http://www.bbc.com/earth/story/20150713-the-truth-about-vultures|title=The truth about vultures|last=Nicholls|first=Henry|access-date=2016-10-21}}

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".{{cite web|title=Stench Gas|url=http://www.zacon.ca/stench-gas.asp|publisher=Zacon Ltd.|access-date=20 February 2015|archive-url=https://web.archive.org/web/20150403223737/http://zacon.ca/stench-gas.asp|archive-date=3 April 2015|url-status=dead}} 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".{{cite web|title=Occupational Health and Safety Act: R.R.O. 1990, REGULATION 854 MINES AND MINING PLANTS Sect. 26(6)(a) |date=24 July 2014 |url=http://www.e-laws.gov.on.ca/html/regs/english/elaws_regs_900854_e.htm|publisher=Ontario Ministry of Labour|access-date=20 February 2015}}

{{Main|Thiol}}

Ethanethiol is a reagent in organic synthesis. In the presence of sodium hydroxide, it gives the powerful nucleophile EtS⁻. The salt sodium ethanethiolate can be generated quantitatively by reaction of ethanethiol with a suspension of sodium hydride in dimethylformamide.{{OrgSynth | author = Mirrington, R. N. | author2 = Feutrill, G. I. | title = Orcinol Monomethyl Ether | volume = 533 | page = 90 | year = 1873 | doi = 10.15227/orgsyn.053.0090}}

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.

• tert-Butylthiol (tert-butyl mercaptan)
• Butanethiol (butyl mercaptan)

{{Reflist}}

• [http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+Ethanethiol NLM Hazardous Substances Databank – Ethyl mercaptan]
• [https://www.cdc.gov/niosh/npg/npgd0280.html CDC - NIOSH Pocket Guide to Chemical Hazards]

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Category:Alkanethiols

Category:Foul-smelling chemicals