Talk:Methanol

--Alex 15:02, 24 July 2006 (UTC)

Methanol Toxicity Contradiction

The beginning of the article (first paragraph) states that "Drinking 1 ml will cause blindness, and as little as 5 ml will cause death," however in the "toxicity" section the article states that "If ingested, as little as 10ml can cause permanent blindness by destruction of the optic nerve. The usual fatal dose is 100–125 ml (4 fl oz)." Could somebody verify the claims and correct this contradiction? Tpingt (talk) 14:22, 29 July 2009 (UTC)

LD50 is 2-7 g/kg in the monkey (http://epa.gov/chemfact/s_methan.txt). So for a 80kg person, that would be 160-560 g (200 - 700ml). SO 100-125ml is maybe a bit low, but not too far out.  Ronhjones  ^(Talk) 23:04, 4 September 2009 (UTC)

Methanol from freezing?

I heard somewhere that if cider is frozen in an attempt to concentrate the alcohol to make applejack, methanol can result. Is this an actual possibility? Where would it even come from? 71.233.255.207 (talk) 15:53, 11 November 2008 (UTC)

Methanol in Tequila

According to this Reuter's report: http://go.reuters.com/newsArticle.jhtml?type=oddlyEnoughNews&storyID=12080476&src=rss/oddlyEnoughNews, methanol is present in greater amounts in pure tequila. Don't know if that should go in this article.

Toxicity

I see Methanol is toxic, but is it also carciogenic in small amounts in the environment? (ie: water table pollution)

Methanol is not classified as carcinogenic, mutagenic, or teratogenic. Small amounts of methanol are actually found naturally in some fruits and other foods. Maximus Rex 02:07, 29 Oct 2003 (UTC)

"Over the course of several days, atmospheric methanol is oxidized by oxygen and sunlight to carbon dioxide. " - presumably this also gives off hydrogen... is this where some/all the hydrogen in the atmosphere comes from? (I know there is very little due to its escape velocity). Need a chemist to update the article. --/Mat 15:46, 13 Mar 2004 (UTC)

When a molecule is photochemically degraded in the atmosphere, the eventual fate of its hydrogen atoms is (usually) water vapor. Shimmin

I was once told that very little hydrogen actually gets away, as ozone will oxidize it readily. Any made on the surface of the earth would probably not make it throught the stratosphere. So I'm told anyway. Vertigre

Can anyone check the figures given that 1ml causes blindness and 4ml kills?

According to the link below it can take 'as little as' 4ml to 10ml to cause blindness, not just a flat 1ml as the wikipedia article states. Also, people have recovered (ie not died!) from up to 500ml to 600ml so 4ml is unlikely to kill I feel. http://www.inchem.org/documents/pims/chemical/pim335.htm#4.%20USES/HIGH%20RISK%20CIRCUMSTANCES%20OF%20POISONING

Methanol Corrosiveness?

I think methanol is also corrosive. I recall an engineer friend complaining that his engine parts don't tend to survive with methonal.

Methanol is not corrosive. When burned in an engine not designed for it, though, some of its combustion products can attack engine parts. Shimmin 11:31, Aug 21, 2004 (UTC)

I disagree. Don't have a reference off hand, but I recall reading that there have been experiments with cars which can burn either gasoline or M85 (85% methanol, 15% gasoline). They required the fuel system to be upgraded so the methanol would not corrode it. The gasoline was necessary to start the engine when cold. pstudier 20:31, 21 Aug 2004 (UTC)

Methanol does etch the more active metals (Mg, Zn, Al ...), but iron, many steels, glass, wood, and almost all plastics withstand it. Would you then call methanol corrosive? Would you call water corrosive because it promotes rust? Hydrogen gas corrosive because it weakens steel? Most fluids will adversely affect some solids. A blanket statement like X is corrosive suggests one will get a severe chemical burn if one spills it on oneself, which simply isn't the case. Now, a statement like X corrodes such-and-such a material is an entirely different discussion. Shimmin 03:32, Aug 22, 2004 (UTC)

High methanol-content fuels can attacks the seals (gaskets) in an engine, although they shouldn't attack the metalwork. Physchim62 21:04, 29 May 2005 (UTC)

Methanol-IMFs

I came here looking for information on the types of IMFs that hold Methanol molecules together. Maybe something could be added in the future.

The reason IMFs are not mentioned on this page is because they are the same in methanol as in any other alcohol. —Keenan Pepper 15:38, 13 February 2006 (UTC)

Uses: Formaldehyde

One of the major uses of methanol is in the production of Formaldehylde which is then used to produce formaldehyde-urea resin glue used to glue plywood plys together, and in chipboard. This needs to be added....

Inconsistency: aluminum corrosion

The article currently says:

• One of the drawbacks of methanol as a fuel is its corrosivity to some metals, including aluminium. Methanol, although only a weak acid, attacks the oxide coating that normally protects the aluminium from corrosion:/ 6CH₃OH + 2Al → 2Al³⁺ + 6CH₃O⁻ + 3H₂

Is it me or does that reaction have nothing to do with the oxide coating? Melchoir 22:46, 1 July 2006 (UTC)

Any seepage of methanol through the oxide coating will cause corrosion. The difference between attack by methanol and attack by water is that aluminum methoxide is soluble in methanol, whereas aluminum oxide is insoluble in water: hence the corrosion rapidly stops with water, but continues with methanol. Physchim62 (talk) 15:31, 24 July 2006 (UTC)

I believe that methanol and water both react with aluminum. With water, the reaction stops as the aluminum oxide product forms an impenetrable coating on the 'pure' aluminum. With methanol, the reaction will continue since the aluminum methoxide product is soluble in methanol (where aluminum oxide was not soluble in water). Isn't this a passivation reaction? Maybe link to that article is in order (where it does talk some about aluminum passivation). Bennybp 01:21, 10 August 2006 (UTC)

Is methanol better disinfectant then ethanol

Can anybody tell me: Is methanol better disinfectant then ethanol?

Not really and given its toxicity is not something that you would want to keep around as the risk exceeds the benefit.Bdolcourt 16:43, 1 May 2007 (UTC)

Question: Can methanol be converted to ethanol and if so is it cost effecient? uses of methanol and ethanol as laboratory reagents

Yes, it can. However it requires some fairly aggressive and potentially expensive chemistry to do it. Given that ethanol is made from fermenting sugars, it is unlikely to be cost effective.Bdolcourt 16:43, 1 May 2007 (UTC)

You could oxidize methanol to formaldehyde for one carbon, and for the other, convert methanol to methyllithium via methyl bromide. Combining these gives lithium ethoxide, which you would quench with acid. The result would be stoichiometric quantities of waste salts, and also, you would use stoichiometric quantities of lithium ($95 per kg) and hydrobromic acid, both of which are produced with expensive electrolysis. The reagents and the reaction itself would be extremely (this time, the word "extremely" really is justified) hazardous. So, all sorts of things can be done, but there's no point in most of them. --Vuo 06:58, 23 August 2007 (UTC)

Blindness (permanent?)

Is the blindness caused by methanol permanent, or does vision return after a sub-lethal dose has been fully excreted? --69.157.243.35 23:28, 26 July 2007 (UTC)

See this missive from Cambridge University: "Patients with visual symptoms may develop irreversible visual impairment even with aggressive intervention." Karl Hahn (T) (C) 14:22, 27 July 2007 (UTC)

Methanol production by anaerobic bacteria

Are there any citations for this? I did some preliminary research and couldn't find anything about this.

--vaeiou 01:31, 23 August 2007 (UTC)

Minor Edit

I have deleted these two sentences: "This led to consumer and media problems and the last time out of methanol blends. However, there is still a great deal of interest in using methanol as a neat (unblended) fuel." I have no idea what "the last time out of methanol blends" means, and there is no context to justify discussion of the possibility that pure ("neat") methanol might be a useful fuel.

Douglas Barber 21:38, 1 September 2007 (UTC)

Toxicity in crystals?

When a substance dissolved in methanol crystalises as the methanol is evaporated, do these crystals contain methanol? And what can be done to be absolutely sure no methanol is left? —Preceding unsigned comment added by 87.67.96.13 (talk) 16:48, 9 October 2007 (UTC)

You can dry the crystals and get rid of the methanol. I imagine some traces may remain occluded in the crystals, but not enough to be significantly toxic (unless you plan to eat large quantities of the crystals!) --Itub 09:48, 10 October 2007 (UTC)

What would you mean by "large" :p. I guess I'll tell you right away, a dutch friend of a friend is going to get into psychedelic mushroom growing, and he was wondering about storing them (he really doesn't want to be a dealer), so he looked into "psilocybin extraction". Methanol seamed the best solvent, but he wants to make sure none of it is left in the crystals. 17:44, 10 October 2007 (UTC)

Gas chromatography is typically used to detect methanol. --Vuo 11:20, 10 October 2007 (UTC)

I feel torn between not wanting to appear to condone illicit drug use and the notion that information should be shared. Two points. 1) Those who would assume the risks of imbibing the output of your kitchen chemist friend will probably ingest less than 100 mg of it. If only a small fraction of that is methanol, they would be ingesting much less than that of methanol, which would be roughly one thousandth of the minimum lethal dose. Note that methanol is not a cumulative poison. 2) The Merck Index indicates that both water or methanol would make a suitable solvent for both extraction and recrystallization of this stuff. It also says that crystals from water melt at a different temperature than crystals from methanol. So there is a possibility that crystals from methanol are an alcoholate form -- that is that methanol might be incorporated as a part of the crystal structure. But if so, you would expect most of the methanol to boil away when the crystals are melted. This also suggests that after recrystallizing from methanol, your friend could dissolve the result in boiling water and recrystallize again. FYI: Merck also says of psilocybin, "Caution: May produce serious psychological disturbances." Karl Hahn (T) (C) 03:10, 11 October 2007 (UTC)

Methyl Hydrate wrongly redirected

I came to look up methyl hydrate, which is a potential energy source located on the sea floor. I was redirected to methanol but there is no discussion on methyl hydrate here...so why was it redirected? It should be a separate article. --Bobkeyes (talk) 00:47, 28 March 2008 (UTC)

Do you mean Methane clathrate?

Ben (talk) 02:50, 28 March 2008 (UTC)

I would "second" this call for correcting the main article... but I was (partly) wrong... see below...

... my university course in organic chemistry was a while ago, and in normal conversation I would be "sure" that the redirection is "just WRONG", but can't be sufficiently sure to mess with the Wikipedia page... but, please, someone with the right qualifications consider? Feel free to tell me I'm wrong! I think Methane clathrate is exactly what most people mean by methyl/ methane hydrate/ hydride, and believe all of the names valid, if not "PC". If someone KNOWS this is right, perhaps some re-directs should be set up for people coming across the other names?? this, after all, is an important chemical, not something obscure. There are significant deposits in the Carribean. A slight drop in ocean levels, as might arise if the Gulf Stream gets "switched off" (See Shutdown of thermohaline circulation) and the arctic gets cold, accumulates water on Greenland etc, would reduce the pressure over the Carribean deposits... leading to their breakdown and the release of large amounts of methane into the atmosphere.... leading to more global warming. Isn't the science of climate change fascinating??... Heating leads to cooling leads to heating! (See clathrate gun hypothesis)

Tkbwik (talk) 14:29, 21 January 2009 (UTC)

I don't think all of those terms are valid. At best they are ambiguous.

Methyl hydride is H₃C-H, i.e. methane. Methane hydrate would be CH₄·H₂O or CH₄·xH₂O, the latter of which is at least consistent with a methane clathrate cluster.

Methyl hydrate could mean a combination of the methyl cation, [CH₃]⁺, and a water molecule, giving methanol protonated on oxygen, [H₃C-OH₂]⁺.

Ben (talk) 16:27, 21 January 2009 (UTC)

P.S. from Tkbwik: Thank you Ben! And thanks also to the Wikipedia page about hydrates. ("Hydrate" is used differently in organic and inorganic chemistry, I've learnt.) I am now better informed, and further thanks, Ben, for the "See..." you put on the methanol article, to get people to where they might be wanting to go.

Not To Be Confused With....?

Not going against anyone's ideas but who could possibly get confused with Methanol and Menthol?!! Kind of funny really.

-Peace Out!-

mÆniac ^Ask! 19:24, 9 September 2008 (UTC)

The words look similar in print if you are not paying attention, I guess. Or maybe certain politicians could pronounce one when they mean the other. ;-) --16:55, 15 September 2008 (UTC)

Molecular formula

Sounds to me it should be CH4O, not CH3OH. --193.49.97.126 (talk) 14:54, 18 September 2009 (UTC)

Yes, the molecular formula is CH₄O. In this case (but not for all molecules), CH₄O is also the empirical formula. CH₃OH is a text formula that attempts to indicate the connectivity of the molecule.

Ben (talk) 15:06, 18 September 2009 (UTC)

Methanol molecular formula is wrong

In the properties bar on the right side of the article it says that the chemical formula is CH4O, that is incorrect. It should say, CH3OH. What kind of a dumb ass wrote this article? Doesn't even know basic chemistry.