Talk:Methyl iodide

From Wikipedia, the free encyclopedia
Jump to: navigation, search
WikiProject Chemicals / Core  (Rated B-class, High-importance)
WikiProject icon This article is within the scope of WikiProject Chemicals, a daughter project of WikiProject Chemistry, which aims to improve Wikipedia's coverage of chemicals. To participate, help improve this article or visit the project page for details on the project.
B-Class article B  This article has been rated as B-Class on the project's quality scale.
 High  This article has been rated as High-importance on the project's importance scale.
Taskforce icon
This is a core article in the WikiProject Chemicals worklist.
 
WikiProject Molecular and Cellular Biology  
WikiProject icon This article is within the scope of the WikiProject Molecular and Cellular Biology. To participate, visit the WikiProject for more information.
 ???  This article has not yet received a rating on the project's quality scale.
 ???  This article has not yet received a rating on the project's importance scale.
 

references[edit]

What's with the odd duplicaiton of numbers? --Belg4mit 02:39, 17 October 2007 (UTC)


According to most MSDS iodo methane is a possible carcinogen. I will add that statement. Also I changed the NFPA diamond rating according to the Sigma-Aldrich MSDS (3-0-1)Xenofonos (talk) 17:16, 3 April 2008 (UTC)



Crazy formulas![edit]

I can't really call myself a very good chemist as my formal education on the matter isn't too great but this: 5 CH3OH + P + 2.5 I2 → 5 CH3I + H3PO4 + H2O

Just has to be wrong.. For one, can't say I've ever heard of a half DIATOMIC (note the di) molecule before... Just how do you add half a dimolecule to a reaction?? Can't be done!

Matter of fact, I've seen plenty of half diatomic molecules and strange uneven numbers in formulas when browsing wikipedia.. (But never EVER in real chemistry books or such) So whoever you got writing them should be "fired" or whatever..

Second, even if you make the numbers even (and the dimolecules whole) by doubling them.. It still doesn't add up. Since the iodinating reagent is PI3 then there is too litte P per I. 2P + 5I2 can't create enough PI3 to make 10 units of CH3I. Actually, NOTHING in the formula seems to add up..

So I'd say the correct reaction(s) would be:

4P + 6I2 -> 4PI3

PI3 + 3CH3OH -> 3CH3I + H3PO3

Or put as one reaction: 4P + 6I2 + 12CH3OH -> 12CH3I + 4H3PO3

So even the Phosphoric acid (H3PO4) is wrong, it's actually Phosphorous acid. (H3PO3) So unless someone here is interested, I'm eventually going to change it myself. —Preceding unsigned comment added by 90.227.181.98 (talk) 22:35, 22 August 2008 (UTC)

I do not see a need to balance the equation at all, it is just confusing and does not tell us much about the mechanism. Why not simply use the reagent-over-the-arrow/byproducts-under-the-arrow notation? Cacycle (talk) 23:06, 22 August 2008 (UTC)


Maybe it's cause english isn't my first language but you just lost me.. Just what is the "reagent-over-the-arrow/byproducts-under-the-arrow notation"? Also, if by equation you mean the formula in the article.. You didn't notice it's incorrect altogether? It doesn't need to be "balanced" but replaced. The number of units in the one in the article are incorrect, and so are the listed products of the reaction. —Preceding unsigned comment added by 90.227.181.98 (talk) 00:22, 23 August 2008 (UTC)
Chemical reaction of methanol to methyl iodide in the presence of red phosphorus and iodine
Cacycle (talk) 02:02, 23 August 2008 (UTC)


LMAO! Now when I see it, I can't believe I didn't get what you meant. Do I feel like a dumbass now..
I like it, pictures say more than a thousand words and all and are v. user-friendly. Though personally I think the H3PO3 should be added to it.. to explain where that phosphorus goes. And also, IMO - Pictures are useful as an addition, but they can't really replace normal formulas.. Not sure if that's what you're proposing doing though. —Preceding unsigned comment added by 90.227.181.98 (talk) 03:10, 23 August 2008 (UTC)
Like this?
CH3-OH
P, I2
Reaction arrow right
- H3PO3
CH3-I
Cacycle (talk) 05:25, 23 August 2008 (UTC)


Yup. That works for me. —Preceding unsigned comment added by 90.227.181.98 (talk) 12:31, 23 August 2008 (UTC)

Proposal: Change the name of this article to "Methyl iodide".[edit]

I propose we change the name of this article to methyl iodide, as this name gets more hits on google, google scholar, and google news. FWIW, in my undergraduate and graduate experience, methyl iodide was used for commonly by my professors and colleagues and text books than iodomethane.Yilloslime TC 17:23, 25 September 2009 (UTC)

I would like all the halomethanes to have a consistent title, so if iodomethane is renamed to methyl iodide, then bromomethane should be methyl bromide, etc. It doesn't make too much difference to me which way they are named, as long as it's consistent. -- Ed (Edgar181) 19:53, 25 September 2009 (UTC)
Well I think the same is true for MeBr and MeCl, i.e. that most people and sources call them methyl bromide/chloride, not bromo/chloro-methane. So IMHO those should be changed too. Not sure about MeF. And I'm not convinced that consistency is the be all and end all, anyway, but I guess that's moot b/c I think they all should be changed, based on there own merits. Yilloslime TC 20:06, 25 September 2009 (UTC)
I support the renaming of this article as methyl iodide. And the related compounds. My guess is that this change is noncontroversial.--Smokefoot (talk) 14:33, 4 October 2009 (UTC)
Alright then. I'm gonna go for it. Yilloslime TC 18:57, 4 October 2009 (UTC)

1. California news is not necessarily noteworthy news... and 2. methylation business[edit]

I agree that if one lives in the American province of California, their recent regulations are of interest. But my feeling is that Wikipedia should steer away from being US-centric. Citing recent newspaper articles is probably too local and too newsy (also the articles failed the NPOV grounds, insinuating that the ruling was a bad idea (probably is in my mind, too)) That is what I though WP:NOTNEWS and WP:SECONDARY and other guidelines are about. Again, my heart goes out to those disappointed by the local regulations, but we dont report on provincial regulations in other parts of the globe. I thought that this is obvious, but other experienced editors seem to disagree, and I look forward to comments on why California rates so highly.

On the methylation business, I was thinking about moving most of the methylation content to Methylation. Just a thought. It seems that evaluating relative qualities of MeI vs MeCl vs Me2SO4 are more appropriate in an overview. --Smokefoot (talk) 18:39, 6 December 2010 (UTC)

Actually, it's likely that this will become big news because California went through the LBAM crisis just in the past couple of years which involved many state officials, lawsuits, national media, etc. We will likely need to create a whole page on this issue along the same lines because even more people are already involved, not just in CA, but nationally. GreenIn2010 (talk) 20:01, 6 December 2010 (UTC)
Methyl Iodide is an import laboratory reagent and it's chemistry is also interesting, mainly since it nicely illustrates nucleophilic substitution. But it's also a pesticide, and a highly controversial one at that, and that's not something we can ignore and still remain WP:NPOV. Do a google news archive search: most of the hits are about this controversy--we can't ignore that. We have plenty of articles on pesticides, and many articles on controversial ones like atrazine, endosulfan, and DDT. I don't see any justification for treating MeI differently. Though the article doesn't currently reflect it, the registration of MeI as a pesticide by the US EPA in 2007 was highly controversial, so this isn't something of California interest only. And, though the article doesn't reflect it, MeI was recently registered as a pesticide in Japan, Mexico, and several other countries, including if memory serves me--Australia. So this isn't just a US use only.

I agree that the article could do a better job describing its pesticide use and the surrounding controversy--and to do it in a less California-centric manner--than in this version. But having said, I think this version is better than not having it discussed at all. I don't have a ton of time to put into WP these days as my contribution log attests, but I'll try to keep an eye this and clean it up a bit. Yilloslime TC 20:45, 6 December 2010 (UTC)

What toxic effects[edit]

Article previously said "Breathing methyl iodide fumes can cause lung, liver, kidney and central nervous system damage. It causes nausea, dizziness, coughing and vomiting. Prolonged contact with skin causes burns. Massive inhalation causes pulmonary edema.[citation needed]" but someone removed that. Can anyone find a source or say what the effects of acute or chronic exposure are ? Rod57 (talk) 14:31, 26 April 2011 (UTC)

Here from the CDC: http://www.cdc.gov/niosh/npg/npgd0420.html
And from the USDA (contains info but I'm not sure about effects) : http://ddr.nal.usda.gov/bitstream/10113/28473/1/IND44184498.pdf
This came up in the search as well: http://www.cdpr.ca.gov/docs/risk/mei/comments/panna_mei_attach1.pdf Gandydancer (talk) 15:20, 26 April 2011 (UTC)
One can say those things about almost any organic compound, especially halogenated ones. So in general we in WP-Chem dont add such routine information (we also avoid advice). But recent editors have an agenda in mind related to legislation in a US state, so I wont be messing with this article any more for a while.--Smokefoot (talk) 17:36, 26 April 2011 (UTC)
Thank you both. For the sake of the non-organic chemist general reader it seems helpful to include such routine information - quantified if possible so toxicity can be compared to other compounds. Rod57 (talk) 20:53, 26 April 2011 (UTC)
Yes, I agree. Like most of us, I'm not a chemist. I'm a gardener. I have no "agenda in mind related to legislation in a US state". Actually I have no idea why I had this article on my watch list and I just read and overlooked Smokefoot's edit. But Rod's post caught my interest and I've learned a lot. I have been working on the organophosphate chemicals and they all contain toxicity, etc., info. This one should as well. I do not consider this information "advice". Gandydancer (talk) 21:54, 26 April 2011 (UTC)

none detected in food supply (unsourced)[edit]

"Neither the U.S. Department of Agriculture nor the U.S. EPA has measured detectable residues of methyl iodide or any other soil fumigant in the food supply or in fruit or produce grown in methyl iodide-treated soils.[citation needed]"

This line strongly implies (1) that the DoA and the EPA have actively been looking for the chemical and (2) the crops grown in methyl iodide-treated soils have entered to food supply. Since they only start using this stuff 2 months ago I doubt that any crops grown in methyl iodide-treated soils have entered to food supply yet. Can anyone verify this? — Preceding unsigned comment added by Tdc204 (talkcontribs) 07:12, 19 July 2011 (UTC)

I was looking for a source for that info...but the following came up from a mother/child forum in a discussion about concerns over giving kids strawberries:

According to Wikipedia, "First commercial applications of MIDAS soil fumigant in California began in Fresno County, in May, 2011. Since that time, it has been applied to soils used to grow a variety of crops. Since its federal registration, more than 17,000 acres of cropland have been treated with MIDAS products without a single health or public exposure incident. Neither the U.S. Department of Agriculture nor the U.S. EPA has ever measured detectable residues of methyl iodide or any other soil fumigant in the food supply or in fruit or produce grown in methyl iodide-treated soils."

[REPLY] I'm not sure of the souce for information from the wikipedia entry. But I do know that just last month, 40 independent scientists, including 3 Nobel Laureates in Chemistry, have appealed to EPA Administrator Lisa Jackson to eliminate the use of methyl iodide. Enough for me to be concerned and want to learn more!

[REPLY] Wikipedia can be changed by anyone, just an FYI, not a reliable source of information.

[REPLY]Let me educate you here too! Before a change is made it must be validated. We used to tell our students that Wikipedia is not reliable because it could be changed by anyone, but that is not the case any more. The changes must first be investigated. Are you sure you're not the ignorant one?

[REPLY]Wikipedia can be changed by anyone but is usually changed back in a matter of seconds. Go change an article and see how fast it gets changed back.

[REPLY]Wikipedia is NOT a valid source. My college does not allow it as a credible source when writing a paper.

[REPLY]Umm...I've already graduated and have my Master's and I used to teach it wasn't reliable too! But as just mentioned there are now guidelines in place so that only reliable and credible information can submitted.

For this reason I'm going to delete that information because I can't find a source for it. Gandydancer (talk) 16:45, 21 July 2011 (UTC)

Looking though the history I find that an anon made about a half a dozen edits, all unsourced, and the above was one of them. The others are now gone as I just removed the last one. Gandydancer (talk) 17:53, 21 July 2011 (UTC)