Sauron
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CS2 at Lowerr Cost
One of the things that has always slowed me down about proceeding with projects related to CS2 is the cost.
Typically I was seeing prices like $180/liter
But now Acros, while still listing expensive grades, is also listing a "for analysis" grade of CS2 for $91/2.5 LitersSo I hope this is not a misprint.
A liter of CS2 is 1260 g or about 16.5 mols. So this is little more than $2 a mol.
CCl4 here we come.
This also has implications for synthesis of MeSCN
There are two eoutes, one is MeI and KSCN and the other starts from CS2 which is converted in two steps to NH4SCN and then to its barium salt which is
reacted with Me2SO4.
The MeI methos is costly even if you make your own MeI simply because KI and I2 are expensive.
The CS2 route given cheap CS2 comes to the rescue. MeSCN is a source of DIY cyanuric chloride (CC, TCT) for those who cannot buy it. I can and do buy
it so MeSCN is not so interesting for me personally. At $27/mol it is more than 10x the cost of CS2 so as a way to make CCl4 it is ludicrous - unless
you also need TCT.
Sic gorgeamus a los subjectatus nunc.
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Jor
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Wouldn't MeBr work instead of MeI, seems much cheaper and somewhat safer. MeBr is readily generated by H2SO4/KBr/MeOH.
So you are going to buy CS2 and make CCl4 from it? A detailed write up with pictures would be nice 
I am blessed, that IF I need CCl4, wich i don't, I can buy a liter for about 35 EUR. 
Acros lists it for 100+ EUR a liter. Wasn't the stuff like 1$ per liter several decades ago?
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Sauron
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Yeah it used to be cheap as dirt
Where I live it is banned (along with chlorogotm, ethylene chloride, ethylene bromide, etc.)\\
MeBr might work but is a gas and so not so convenient.
Yes I will do an Illustrious Pragmatic Guide to making CCl4. It is a two step process from CS2 and lots of Cl2. In the first step using iron filings
or FeCl3 catalyst, CCl4 and sulfur chloride form according to
2 CS2 + 6 Cl2 -> 2 CCl4 + 2 SCl2
This is a rapid reaction and goes to completion
In the second step anothyer mol CS2 is added and the mixture is reluxed, the SCl2 loses chlorine and sulfur precipitates, this is a slow equilibrium
and so is favored by excess CS2 and removal of as much CCl4 as possible beforehand. It proceeds to about 70% according to
CS2 + 2 SCl2 -> CCl4 + 4 S
If you combine these equations the overall process
3 CS2 + 6 Cl2 -> 3 CCl4 + 6 S
and a 90% overall yield.
The final mixture is CS2, CCl4, SCl2 and S2Cl2, and S solid and in solution. Various strategies for purification have been used, proposed, and
patented.
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Sauron
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Jt is worth mentioning that the I2 catalyzedd chlorination of CS2 at <40 C and out of sunlight gives a different product, CSCl4, along with the
usual sulfur chlorides. But treatment with Fe or FeCl3 converts this quantitatively to CCl4. The mixture is then worked up as described above.
The complication in both instances is that one never obtains (without special methods) only SCl2, but rather a mix of SCl2 and S2Cl2. If you look at
the bp's you will see the hassle. ACl2 is unstable and is in equilibrium with S2Cl2. It boils at same temperature as CCl4. S2Cl2 is stable, and boils
at about same temperature as CSCl2.
Fortunately the SCl2 <=> S2Cl2 equilibrium can be manipulated thermally and a fractionable two component mixture obtained. This is the AKSO
process developed by Rupp and Meyer. I have described it previously and posted the papers and patents.
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chief
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Shouldn't cheap S2-vapor (from sublimated Sulfur) react with some carbon (from decomposed sugar) under glowing-heat ?
This then would give very-high- purity CS2, with some trace-amounts of sulfur dissolved in it, could be distilled ...
Cost would be below 5$/liter .
(He ain't no chemist who never sublimated sulfur or crystallized sugar ...)
[Edited on 24-3-2009 by chief]
[Edited on 24-3-2009 by chief]
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DJF90
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How about this: Chlorinate your CS2 with iodine catalyst, to obtain the CSCl4. Treat with Fe or FeCl3 to convert quantitatively to CCl4. You should
now have a mixture of CCl4, SCl2 and S2Cl2, with small quantities of inorganics and unreacted CS2. To get your CCl4 by distillation its the SCl2 that
poses the problem. So add some sulfur and reflux, as this converts the SCl2 into S2Cl2, allowing you to then fractionate to obtain your CCl4. IIRC,
Klute used sulfur like this when making S2Cl2, so I don't see why it wouldnt work here.
@chief: Did you not see the thread on CS2 synthesis from sulfur and charcoal? I suggest you go read it, and you will see things are not as simple.
[Edited on 24-3-2009 by DJF90]
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Sauron
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If you go the I2 cat.route, better to distill the mixture priorto reduction w/Fe and get rid of the low boiling SCl2.
THEN reduce the CSCl4 (which is very basty toxic stuff) to CCl4, now you can cleanly seperate it from S2Cl2 by fractionation.
And remember CS2 + 2 SCl2 = CCl4 + 4 S
The bulk of the SCl2 is destoyed in this step
It is worth mentioning that CS2 can be chlorinated by SbCl5 either stoichiometrically or catalytically. In either case the trichloride precipitate can
be reconverted to pentachloride. This allows preparation without direct use of Cl2 gas.
Lower chloromethanes can be photolytically chlorinated in vapor phase - chloroform for example if distilled in a rapid stream of dry Cl2 under UV or
sunlight is converted to CCl4. I have hopes that this also works for DCM -> CHCl3 -> CCl4.
[Edited on 25-3-2009 by Sauron]
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pawan
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Dear Sauron
I found some work from a very good company on S2Cl2 can be prepared by molten S & chlorine at 105 DegC, But I am not sure as this article
discusses different possibilities.
Can you tell me more references including patent of rupp/meyer.
I was also thinking of making this liquid using CS2 & chlorine rather than going for more hazardous S + Cl2 reaction.
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Sauron
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This thread is about CS2 not S2Cl2.
In other threads the methods decribed above have been shown to be uneconomical.
Don your homework before asking anything.
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