Natures Natrium
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Tear gas from SO2Cl2 + LiOMe?
As a wise man once said, "Oh God, my eyes!" 
I recently was trying to be clever by attempting a sythesis of dimethyl sulfate which didn't appear to have been explored in either literature
nor on this board.
Sulfuryl chloride was made by passing SO2 and Cl2 through activated carbon (following the procedure outlined in Inorganic Laboratory Preparations,
Schlessinger, p. 121), which went very smoothly and exactly as described. I acquired some 31.4g (233 mmol) of SO2Cl2 which was purified by shaking
with 3g of Hg to remove free chlorine, then distilled.
Lithium methylate (CH3OLi) was made by reacting 3.2g of lithium metal with 150mL of 99.9% HPLC grade MeOH. This was cooled and filtered to remove a
small amount of insolubles, mostly MnS (from AA batteries) I believe.
I was following patent 3,020,303 ( http://patft.uspto.gov/netahtml/srchnum.html ) as a general guideline, the only exception being that I was operating sans an inert gas since I
intended to vacuum distill the product anyways.
I was rather suprised to find that addition of SO2Cl2 even to plain MeOH caused a violent enough reaction to pop and sizzle a bit when the two are
mixed. I found this suprising considering how stable SO2Cl2 is towards water.
Anyways, I proceded with the expieriment, adding the SO2Cl2 through a claisen adapter with a 300mm west on the other joint. I stopped the dripping
when I noticed an odd white vapor escaping the top of the condenser. It had no immeadiate smell or taste, and when I let the vapor touch a piece of
wetted pH paper I got an instant strong acid reaction. Well, more than a little dissappointed that things weren't going my way, I decided to
call it quits for the moment. So, I closed the valve on the addition funnel. Why is it that one always makes the stupidest mistakes at the worse
possible time? Instead of closing the valve I had opened it wide open. The condenser started puffing whitish vapor like an old steam powered train,
and well over half my SO2Cl2 was gone before I could shut it off.
That was when my eyes suddenly caught fire, and inhalation of just a small bit of air left a burning sensation in my throat. Working as quickly as I
could while holding my breath and blind, I set my lab to "Vent Everything" and bailed. Walking back in a couple of minutes later I was
suprised to find my eyes instantly on fire again, and so I decided to leave it alone for a bit.
I havent worked up what remains in the flask, though I have my doubts regarding my intended product. I just wanted to share that near as I can tell
the reaction:
SO2Cl2 + 2LiOMe -> 2LiCl + Me2SO4
does not work. Also I wondered if anyone can guess as to what the products were, including this gas which hopefully wont prove to be any more of a
health hazard than just being an acidic tear gas.
I also thought that
2MeOH + SO2Cl2 -> 2HCl + Me2SO4
since
2H2O + SO2Cl2 -> 2HCl + H2SO4
although I suppose
2MeOH + SO2Cl2 -> 2MeCl + H2SO4
could be possible, but it doesnt account for the acidicity of the white vapor. I choose to work with an alkali metal alcoholate just because I
thought initially the reaction between sulfuryl chloride and methanol would be too slow!
Any ideas, anyone?
[Edited on 12-7-2005 by Natures Natrium]
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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runlabrun
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HCl gas is a possibility, hope you didnt catch to much that would be very damaging to your eyes and skin (eeewww).
MeCl is very toxic so you would be very sick, dont think it was this though.
I think your pretty right, it would have been just some HCl so as long as you did a great big eye wash to be sure to get it all and its all good now
(ie you can see ok) then its all good, MeCl would have made you quite ill (even in small concs its very bad).
-rlr
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12AX7
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I don't know if pure HCl has any odor, but my muriatic acid smells kinda icky like sulfur almost, besides of course the acid effects from the
vapor.
Tim
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garage chemist
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What made your eyes sting is Chlorosulfonic acid methylester, CH3O-SO2-Cl. A potent lachrymator which has been used as a war gas.
It is commonly prepared by slowly dripping methanol into sulfuryl chloride while cooling with ice, then boiling away the HCl, rapidly washing the
substance with ice water and distilling it in vacuum (I have a procedure).
With water, it hydrolyzes to methylsulfuric acid and if water is present in excess, the methylsulfuric acid hydrolyzes further to sulfuric acid
and methanol.
(Unfortunately, I don't know if it reacts with methanol).
Note that heating methylsulfuric acid in vacuum causes it to decompose into sulfuric acid and dimethyl sulfate, the latter distills over as it is
formed.
Dimethyl sulfate is normally prepared by reacting chlorosulfonic acid with methanol and heating the formed methylsulfuric acid in vacuum as described
above.
I highly recommend to download "The War Gasses" from the Library, it's from there where I got all the above information.
How do you feel? Did you notice any delayed effects of the lachrymatory fumes?
Please be careful with such experiments in the future. Me2SO4 is even more toxic than HF in regard to exposure by skin absorption, and also a lethal
and non- detectable inhalative poison. Working without a fume hood is suicide.
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Natures Natrium
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Mmm, yea
| Quote: | Originally posted by garage chemist
What made your eyes sting is Chlorosulfonic acid methylester, CH3O-SO2-Cl. A potent lachrymator which has been used as a war gas.
It is commonly prepared by slowly dripping methanol into sulfuryl chloride while cooling with ice, then boiling away the HCl, rapidly washing the
substance with ice water and distilling it in vacuum (I have a procedure).
With water, it hydrolyzes to methylsulfuric acid and if water is present in excess, the methylsulfuric acid hydrolyzes further to sulfuric acid
and methanol.
(Unfortunately, I don't know if it reacts with methanol).
Note that heating methylsulfuric acid in vacuum causes it to decompose into sulfuric acid and dimethyl sulfate, the latter distills over as it is
formed.
Dimethyl sulfate is normally prepared by reacting chlorosulfonic acid with methanol and heating the formed methylsulfuric acid in vacuum as described
above.
I highly recommend to download "The War Gasses" from the Library, it's from there where I got all the above information.
How do you feel? Did you notice any delayed effects of the lachrymatory fumes?
Please be careful with such experiments in the future. Me2SO4 is even more toxic than HF in regard to exposure by skin absorption, and also a lethal
and non- detectable inhalative poison. Working without a fume hood is suicide. |
Thanks for the information garage chemist, and the concern is appreciated too. I am doing just fine, probably because as soon as my eyes started
stinging and I got a little whiff in my mouth, I knew I had fucked up and was dealing with some nasty shit. I never actually inhaled any of it, thank
goodness, but my eyes were stinging for quite some time.
Indeed, I find I have to stop myself and slow down on many occassions, since my exuberance at continually reaching higher levels of understanding in
this endlessly fascinating field tend to cloud my judgement with haste. No question, my lab should have been set to "Vent Everything"
before I even started on this experiment, not to mention the fact that some scrub bottles leading off the top of the condenser would have been the
prudent thing to do.
It never even occured to me that the intermediate chlorosulfonic acid would be stable in the presence of methanol and even the alkoxide ion. I wonder
if chlorosulfonic acid methyl ester forms an azeotrope with methanol? That, or most of it just managed to escape as the nasty war gas, since
distillation of the alcohol yielded nothing.
This new information is certainly interesting, however it is my intention to proceed with a little more care towards my own personal safety.
Hmm, now for some musing.
I wonder if adding a solution of methyl chlorosulfonic acid in methanol to a solution of lithium alkoxide would yield dimethyl sulfate directly? This
would be based on the assumption that most of the chlorosulfonic acid escaped in my attempt. The temperature of the methanol solution when I did it
was not moderated in any way, since the patent I had gotten the idea from recommended a temperature of roughly 60C which would be perfect for just
letting the methanol reflux.
I wonder if methyl sodium sulfate also disporportionates when exposed to heat under vacuum? Either way that is quite interesting, since I know of
reports of monomethyl sulfates being prepared and isolated by hobby chemists with just methanol and concentrated sulfuric.
However, seeing as I have access to SO2Cl2, I think it would be interesting to pursue it via this route. Actually, in light of all the new info, I
cannot help but think that other than my lack of proper safety procedures my biggest mistake was simply to not keep the flask ice cold during the
addition. I still find it hard to believe that methyl chlorosulfonic acid would not react with lithium methoxide.
Well, as the engineers say, back to the drawing board. 
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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S.C. Wack
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In this 1919 French article, the authors did not get much methyl sulfate by heating Na or K methyl sulfate, they got methyl ether instead.
They had better results with the Li, Ca, Ba, and Sr salts, without vacuum.
Attachment: methyl_sulfate.pdf (153kB)
This file has been downloaded 854 times
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Natures Natrium
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Oh, very nice article.  Um, I can't read french though. On the third page
it is obvious that they are talking about the different salts attempted. If I am not mistaken, are they saying that the calcium and barium salts
decomposed at 200C, and that the strontium salts decomposed at a mere 100C? If so, that's pretty amazing stuff, although it makes sense since
the only way a Group II salt could form would have to be Ca(MeSO4)2. Too bad I dont have any strontium around, although I do have both barium and
calcium in abundance.
\"The man who does not read good books has no advantage over the man who cannot read them.\" - Mark Twain (1835-1910)
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