Everything about Methanethiol totally explained
| Section2 =
}}
Methanethiol (also known as
methyl mercaptan) is a colorless gas with a smell like rotten
cabbage. It is a natural substance found in the
blood,
brain, and other animal as well as plant tissues. It is disposed of through animal
feces. It occurs naturally in certain foods, such as some
nuts and
cheese. It is also one of the main chemicals responsible for
bad breath and the smell of
flatus. The
chemical formula for methanethiol is
CH3SH; it's classified as a
thiol.
Occurrence
Methanethiol is released from decaying organic matter in
marshes and is present in the
natural gas of certain regions, in
coal tar, and in some
crude oils.
In surface seawater, methanethiol is the primary breakdown product of the algal metabolite
dimethylsulfoniopropionate (DMSP). Marine bacteria appear to obtain most of their protein sulfur by the breakdown of DMSP and incorporation of methanethiol, despite the fact that methanethiol is present in seawater at much lower concentrations than sulfate (~0.3 nM vs. 28 mM). Bacteria in oxic and anoxic environments can also convert methanethiol to
dimethyl sulfide (DMS), although most DMS in surface seawater is produced by a separate pathway. Both DMS and methanethiol can be used by certain microbes as substrates for
methanogenesis in some anoxic sediments.
Methanethiol is a weak
acid, with a
pKa of ~10.4. This acidic property makes it reactive with dissolved
metals in aqueous solutions. The
environmental chemistry of these interactions in
seawater or fresh water environments such as
lakes has yet to be fully investigated.
The United States
material safety data sheet (MSDS) lists methanethiol as a colorless, flammable gas with an extremely strong and repulsive smell. At very high concentrations it's highly toxic and affects the central nervous system. Its penetrating odor provides warning at dangerous concentrations. An odor threshold of 0.002
ppm has been reported. The United States
OSHA Permissible Exposure Limit is listed as 10 ppm.
Uses
Methanethiol is manufactured for use in the
plastics industry and as a precursor in the manufacture of
pesticides. It is also released as a decay product of
wood in
pulp mills. Due to the extremely low odor threshold of
thiols in general, they may be added to otherwise odorless gasses, enabling people to detect leaks by smell.
St. Petersburg incident
On
December 26,
2005, dozens of people at a
St. Petersburg, Russia Maksidom home supplies store became ill when gas suspected to be methanethiol was released. The store had received letters threatening to disrupt business during the
winter holiday season. Three other stores belonging to the same chain found boxes with glass containers and timers that also might have been rigged to release the gas.
Asparagus
Methanethiol is assumed by some to be a byproduct of asparagus metabolism in some people. It is thought to be responsible for a noticeable change in the odor of urine as early as a few hours after eating asparagus.
Further Information
Get more info on 'Methanethiol'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://methanethiol.totallyexplained.com">Methanethiol Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
