Hexavalent
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Chlorination of DCM
Could not find any information on this anywhere, so here goes. Would it be possible, under the right conditions, to chlorinate dichloromethane to
chloroform and that to carbon tetrachloride?
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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barley81
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http://en.wikipedia.org/wiki/Chloroform#Industrial_routes
That is how chloroform is made. Methylene chloride, chloroform, and carbon tet are all produced by the chlorination of methane or methyl chloride (DCM
should also work because it is an intermediate in the reaction) at 400˚C (according to Wikipedia). Doing that is not very practical for anything
but industry. Luckily, chloroform can be made easily using the haloform reaction.
Edit:
Under UV light it may be feasible. You would need to regulate flow carefully, and have a strong UV source. Why do that when you can just buy
chloroform and carbon tetrachloride (although it's hard to get carbon tet)?
[Edited on 23-3-2012 by barley81]
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weiming1998
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Yes it would be possible, as in the reaction between methane and chlorine, chloroform and carbon tetrachloride is formed, instead of just methyl
chloride and dichloromethane. But to chlorinate dichloromethane, the reactants must be either
.Heated to several hundred degrees
.Under strong UV light
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BromicAcid
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Did some work several years ago chlorinating tetrachloroethylene and trichloroethylene in an attempt to make carbon tetrachloride (which or course
involved scission of the C-C bond). I attached a photo of the apparatus made by using a wooden salad bowl with UV LEDs inserted into it in regular
intervals. The hole in the top was the prefect size for the neck of the flask into which I was leading my chlorine gas. It worked better than I
expected despite the propensity of Pyrex glass for blocking UV as well as the low output of LED UV lights (there is a separate post on this forum
regarding this). Part of the efficacy however was likely due to a small amount of catalytic iodine added at the start of each reaction forming the
iodine monochloride insitu which is more aggressive in chlorination.
Just a word of advice, if you make such an apparatus resist the desire to look directly at it. Despite its beauty it will work hard to kill your
vision just as it works hard to form radicals from your diatomic chlorine.
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peach
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 Love it bromic!
Hex, you may want to make chloroform via the haloform instead, which is the way a lot of people do it. There are many videos on youtube, some of which
are from the members here.
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Magpie
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This should be helpful:
http://www.sciencemadness.org/talk/viewthread.php?tid=1424&a...
The single most important condition for a successful synthesis is good mixing - Nicodem
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Hexavalent
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Yes, yes . . .I always make my chloroform via the haloform reaction, as it is much cheaper, I was just speculating about the reaction. The thing is,
my dad doesn't like bottles of potential anaesthetics in the garage, so I always label it 'trichloromethane' and my diethyl ether as 'Et2O'
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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garage chemist
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Bromic, did that apparatus ever produce any isolatable CCl4?
I would think that adding chlorine to C2Cl4 would first make hexachloroethane and solidify the reaction mixture before further reaction. What were
your observations?
Hexavalent, I'd recommend that you try out chlorination of DCM with chlorine in sunlight using catalytic iodine and a reflux setup.
An old german chemistry book gives a preparation of CCl4 from CHCl3 and chlorine under these conditions.
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Hexavalent
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Thanks, I will try that. Can you provide a link to the book with the instructions in it?
I cannot read German, but can get my teacher at school to translate
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garage chemist
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I posted that preparation here:
http://www.sciencemadness.org/talk/viewthread.php?tid=14927#...
Nobody on this board has attempted it properly before. You can be the first to do so.
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Hexavalent
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Thanks, I assume that with the correct stiochiometry you could make the chloroform from the DCM as opposed to going straight to the carb.tet. . . ??
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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garage chemist
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That probably won't work well, you will always get a mixture of products. If you pass 1 mole of Cl2 into 1 mole of DCM and ensure that all of it
reacts (which is most likely impossible) you will get a mixture of DCM, CHCl3 and CCl4.
Don't try to use stochiometric amounts of chlorine, you will need an excess since the evolving HCl gas will invariably carry a large amount of
unreacted chlorine with it.
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BromicAcid
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Garage Chemist,
When I tried to distill the mixture I did get a small fraction coming over at the proper boiling point for carbon tetrachloride. However the
experiment overall was a failure. After the fact I realized I had been too aggressive with how much material I was trying to chlorinate and I had
added too little chlorine. Still, being a radical reaction it was all over the place giving all the products of the rainbow. The mixture did not
become thick but did begin to precipitate crystals. Attached is a picture of the mixture after I filtered it and before distilling it. Crystals
again precipitated out after filtering so the liquid must have been saturated with the hexachloroethane.
 
Edit: Wow... this was 7 years ago...
[Edited on 3/24/2012 by BromicAcid]
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Hexavalent
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Thanks for that, I might try it soon, modified based on your experiences. Where can one acquire UV LEDs cheaply?
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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Sedit
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What about using something like TCCA as the Chlorine source as it should be easier to handle the gaseous Chlorine.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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barley81
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@Hexavalent:
Radioshack sells 'em. Alternatively you can buy some from eBay.
<a
href="http://www.ebay.com/itm/100-x-5mm-Bright-UV-Purple-5000-mcd-LED-Bulb-Light-/150784833665?pt=LH_DefaultDomain_0&hash=item231b79f881">Prett
y good deal.</a> A hundred of them for five dollars. Shipping might be slow from Hong Kong.
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BromicAcid
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There is an interesting article on light and chlorination here:
http://www.faizkaskar.8k.com/light1.html
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Magpie
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And here is some more experience for your perusal:
http://www.sciencemadness.org/talk/viewthread.php?tid=1305&a...
The single most important condition for a successful synthesis is good mixing - Nicodem
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Agecer
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Quote: Originally posted by BromicAcid  | Did some work several years ago chlorinating tetrachloroethylene and trichloroethylene in an attempt to make carbon tetrachloride (which or course
involved scission of the C-C bond). I attached a photo of the apparatus made by using a wooden salad bowl with UV led tube inserted into it in regular intervals. The hole in the top was the prefect size for the neck of the
flask into which I was leading my chlorine gas. It worked better than I expected despite the propensity of Pyrex glass for blocking UV as well as the
low output of LED UV lights (there is a separate post on this forum regarding this). Part of the efficacy however was likely due to a small amount of
catalytic iodine added at the start of each reaction forming the iodine monochloride insitu which is more aggressive in chlorination.
Just a word of advice, if you make such an apparatus resist the desire to look directly at it. Despite its beauty it will work hard to kill your
vision just as it works hard to form radicals from your diatomic chlorine.
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Will they not cause any harm?
[Edited on 28-9-2012 by Agecer]
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kristofvagyok
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Wow, this thead looks like an awesome project.
The lab where I work some cubane have been produced and one of the step were made under UV light, with an UV reactor. It was simple, a mercury vapor
lamp was placed in a reactor and the borosilicate glass was removed from it, the inner quartz tube was shining in the mixture. It produced a lot heat
(more than 100W), so the reactor was cooled with a lot water but it worked.
I would think that a reactor designed similarly to this would work great for this reaction also. A few mW LEDs are not so powerful...
Is there anyone who want to buy something from quarts glass? We've got a lot and they are currently used for... Nothing.
P.S: CCl4 is toxic as hell, don't forget it.
I have a blog where I post my pictures from my work: http://labphoto.tumblr.com/
-Pictures from chemistry, check it out(:
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mr.crow
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I don't think LEDs are going to cut it. They are more like blacklights for glow-in-the-dark minigolf
Putting the bulb in the flask is a good idea (despite the heat). Glass blocks a portion of the UV, that's why they use it for the outer envelope of
high power bulbs
Check out Prepublications for a UV chlorination done by len1
Also watch out for phosgene
Double, double toil and trouble; Fire burn, and caldron bubble
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