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Author: Subject: Chloroform
kemikallyimbalanced
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[*] posted on 31-3-2007 at 18:33
Chloroform


I'm looking for a relatively pure source of OTC chloroform in the USA. Does one exist?

[Edited on 31-3-2007 by kemikallyimbalanced]
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guy
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[*] posted on 31-3-2007 at 18:38


It doesn't get easier than bleach + acetone + ice
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kemikallyimbalanced
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[*] posted on 31-3-2007 at 18:46


Yeah, I read about that on that Rhodium site but I heard it can get out of control. I need to get some quick though so I have been looking at the labels at several stores around here.
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Chris The Great
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[*] posted on 31-3-2007 at 19:03


It also doesn't get more impractical for large scale production than bleach, acetone and ice. Try to make even 250ml chloroform with that method! It works fine for a small scale reaction but will not produce enough chloroform to be of practical use if the chemist is working on anything beyond microscale.

As for the original question, I do not believe that there are any.
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BromicAcid
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[*] posted on 31-3-2007 at 19:52


OTC chloroform is a thing of the past, the EPA regulates anything containing more than 6 ppm chloroform as hazardous waste (D022) so manufacturers tend to shy away from it (that and from a toxicity view). Although the method of production using sodium hypochlorite solutions is inefficient (in a different thread I worked out that a lot of chloroform is lost to solution and I also suspect even more is drawn into solution in the acetone/water mixture left over than in water alone) I also detailed the old method of utilizing the haloform reaction using instead solid hypochlorite that was detailed in one of the older chemistry books. I never got around to using it but the ratios and everything are there. Seriously though, it's easier than buying it and even using the NaOCl method large amounts can be produced, it's just a pain in the butt.

[Edited on 3/31/2007 by BromicAcid]




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kemikallyimbalanced
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[*] posted on 1-4-2007 at 16:53


Damn that sucks. I guess DCM will have to be used then. Thanks
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not_important
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[*] posted on 2-4-2007 at 03:38


Quote:
Originally posted by BromicAcid... Although the method of production using sodium hypochlorite solutions is inefficient (in a different thread I worked out that a lot of chloroform is lost to solution and I also suspect even more is drawn into solution in the acetone/water mixture left over than in water alone)...


However you can concentrate NaOCl bleach by evaporation under reduced pressure, 15 to 30 mmHg & no warmer than 25 C.

The CHCl3 in aqueous solution can mostly be recovered by distillation; some have argued for removing NaOH by treatment with CO2 or NaHCO3, while others think that flash evaporation is the way to go.

You'll still need to work up the recovered CHCl3 as it will also contain water and possibly the carbonyl compound or alcohol you started with plus a bit of CCl4.
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[*] posted on 2-4-2007 at 05:25


how about Cl2 bubbled through NaOH and acetone?

"Yeah, I read about that on that Rhodium site but I heard it can get out of control."

what exactly is out of control??


good day sir
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oxybate
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[*] posted on 25-5-2007 at 11:24


Out of control as in producing Phosgene, not something you want to inhale, and if you do smell it, its already a bit too late.
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[*] posted on 25-5-2007 at 14:49


Its bullshit, the reaction cant produce phosgene. Anhydrous conditions would be necessary for that, and haloform reactions only work in aqueous solutions in the first place.

Still though, 10% NaOCl and acetone can get out of control in the meaning that it gets so hot that the chloroform will violently boil off and you are left with no product.
Only bleach with less than 5% NaOCl doesnt do this, as the heat generated per volume is not enough to heat the solution to the boiling point of chloroform.
With 10% NaOCl it all depends on the amount of ice you are using.
External cooling can also be applied instead but then the acetone must be introduced very slowly to allow for heat exchange to occur.

The yields with NaOCl are indeed low, but only if the chloroform is not extracted by distillation.

Using a solid hypochlorite like HTH calcium hypochlorite is a good way to produce larger amounts of chloroform, but it can only be extracted by distillation since a thick Ca(OH)2 sludge is formed in the reaction.

Good mixing is essential in the haloform reaction. The acetone tends to stay at the surface due to its lower density and is quite reluctant to mix with the solution. Diluting the acetone with two volumes of water can help with that, but it doesnt replace good stirring.




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