Bromine
Harmless
Posts: 45
Registered: 7-9-2006
Location: Slovenija
Member Is Offline
Mood: good
|
|
Bromoform
Does somebody knows how to prepare bromoform, whit chemicals, commonly found in a home lab?
|
|
|
Nick F
Hazard to Others
Posts: 439
Registered: 7-9-2002
Member Is Offline
Mood: No Mood
|
|
Bromine, sodium hydroxide, acetone...
Exactly the same as chloroform, but not using chlorine.
(The Rhodium archives at Erowid will have a chloroform synthesis...)
|
|
|
BromicAcid
International Hazard
Posts: 3227
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline
Mood: Rock n' Roll
|
|
Even more easily, mixing sodium hypochlorite solutions with solutions of say... sodium bromide result in the oxidation of the bromide anion to the
hypobromite and the simultaneous reduction of the hypochlorite to chloride. That said you end up with a soultion of sodium hypobromite by simply
mixing sodium bromide with sodium hypochlorite, avoid bromine alltogether. Then add your acetone. Admittidly I don't know the speed of the reaction
therefore I cannot give you a time that you should allow your bromide/hypochlorite mixture to sit before reacting it and as such there is bound to be
at least some chloroform contamination in your final product but I mentioned this method on this board (somewhere) before and have tried this in
practice with success.
|
|
|
Bromine
Harmless
Posts: 45
Registered: 7-9-2006
Location: Slovenija
Member Is Offline
Mood: good
|
|
I will try to make with bromide/hypochlorite, because i don't want to destroy whole ampule of bromine, yust for making Bromoform.
[Edited on 10-9-2006 by Bromine]
|
|
|
woelen
Super Administrator
Posts: 7977
Registered: 20-8-2005
Location: Netherlands
Member Is Offline
Mood: interested
|
|
I have the impression that you first should mix the bromide with acetone in water (these 3 chems do not react) and then add the hypochlorite. If you
add hypochlorite to bromide, then I'm afraid that you make bromate instead. Hypobromite is very unstable and easily disproportionates:
3BrO(-) --> 2Br(-) + BrO3(-)
Bromate does not make bromoform with acetone, it does not react.
Hypobromite is much more prone to disproportination than hypochlorite.
I, however, suspect that the addition of the hypochlorite to the bromide/acetone mix also may give rise to formation of chloroform, or even mixed
chloro/bromo-compounds.
If I were to make bromoform myself, I would first make bromine from bromide (just in solution, no need to separate from the water). To this I then
would add a solution of acetone in not too highly concentrated NaOH.
|
|
|
Bromine
Harmless
Posts: 45
Registered: 7-9-2006
Location: Slovenija
Member Is Offline
Mood: good
|
|
Well i diceided rawder to buy bromoform , but it is a bitt expensive
EDITED: I won't buy it. It is too expensive. Maybe i can make it with chloroform and KBr, CHCl3 + 3KBr--> CHBr3 + 3KCl, i think it will work?
[Edited on 13-9-2006 by Bromine]
[Edited on 13-9-2006 by Bromine]
|
|
|
Bromine
Harmless
Posts: 45
Registered: 7-9-2006
Location: Slovenija
Member Is Offline
Mood: good
|
|
And there is another problem, on Wikipedia says that bromoform is somehow soulable in water.
|
|
|
Bromine
Harmless
Posts: 45
Registered: 7-9-2006
Location: Slovenija
Member Is Offline
Mood: good
|
|
ops please delete this post
[Edited on 13-9-2006 by Bromine]
[Edited on 13-9-2006 by Bromine]
|
|
|
Mr. Wizard
International Hazard
Posts: 1042
Registered: 30-3-2003
Member Is Offline
Mood: No Mood
|
|
Bromine does react with acetone after being exposed to light to make a rather powerful tear gas, Bromoacetophone. It may not do this in a water
solution but if you dump Bromine into acetone you are going to make it.
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
| Quote: | Originally posted by Bromine
Well i diceided rawder to buy bromoform, but it is a bitt expensive
EDITED: I won't buy it. It is too expensive. Maybe i can make it with chloroform and KBr, CHCl3 + 3KBr--> CHBr3 + 3KCl, i think it will work?
|
The corresponding reaction of alkyl chlorides and bromides with sodium iodide is mostly driven by the insolubility of NaCl or NaBr in the solvent,
usually acetone. With Rcl + KBr you'll find that there is less of a diifference in the solubilities of KCl and KBr, neither is very soluble in
acetone. You might have better luck using NaBr, but I think you'll still not get good conversion.
If you're after bromoform for use as a dense liquid, then using a bromide and hypochlorite should be OK; fractionate the product to remove most of the
chlorform and mixed Cl/Br methanes. Otherwise you're tuck with making bromine.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
