mycotheologist
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Questions about the haloform synthesis using acetone and calcium hypochlorite
I want to try out this reaction now, I've never performed a haloform reaction so I'm just reading various guides at the moment. This one is very
straightforward:
https://www.erowid.org/archive/rhodium/chemistry/chloroform....
but theres a couple of things I don't get. Firstly, it says:
| Quote: |
The chloroform thus obtained is usually acidic. |
why would it be acidic? The next part confuses me too:
| Quote: |
Therefore shake it thoroughly with dilute sodium hydroxide solution in a separating-funnel. (If the chloroform tends to float on the alkaline
solution, it still contains appreciable quantities of acetone: in this case the soda should be run out of the funnel and the chloroform shaken with
water to extract the acetone. |
Firstly, what is the alkaline solution, is it just water with NaOH dissolved in it? Secondly why would chloroform floating above the "alkaline
solution" be an indication of acetone present? I thought chloroform is immiscible with water and thus, forms a separate layer anyway. I know that
chloroform is way more dense than water and should actually be the bottom layer. So whats going on here is that the acetone mixes with the chloroform
and this new mixture has a lower density than water and thus, floats on top of water? I'm mighty confused here. Acetone is also highly soluble in
water, so if what the author is saying is correct, acetone must be REALLY soluble in chloroform. Regardless of that though, I can't see how the
acetone could change the chloroforms density that much. It would depend on how much acetone is present too.
EDIT: I took a look at this video:
https://www.youtube.com/watch?v=Wh_7fjHV_BY
which looked good until the part about leaving it to react for 2 days. Surely the reaction can be done faster than that. Firstly, I was thinking of
having my ice bath on standby and only using it if the solution starts boiling vigorously. Also, I'm thinking of adding a stir bar to facilitate the
reaction. I'm planning on controlling the reaction rate and thus heat generated by adding the acetone in small increments. Does this reaction really
take days to go to completion is was that just due to the conditions in that video?
[Edited on 19-4-2012 by mycotheologist]
[Edited on 19-4-2012 by mycotheologist]
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Nicodem
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Thread Moved
19-4-2012 at 09:18 |
bbartlog
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There are other threads on this reaction in this forum. You could start here: http://www.sciencemadness.org/talk/viewthread.php?tid=9212 ,or UTFSE to find something more specific about calcium hypochlorite.
The less you bet, the more you lose when you win.
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mycotheologist
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I'm in the process of trying this reaction but theres a problem. I've added half of the acetone but the temperature hasn't gone up a single degree.
I've had it in an ice bath from the start and the thermometer says its around 10C. Theres a stir bar in there and I can hear it but its not making the
liquid swirl. Theres lots of undissolved white material (the hypochlorite) in there so its not a solution, more of a suspension. I don't know what to
do. I added a few mils of boiling water and brought the temperature up to 20C but still no temperature rise. Any idea how I can get this reaction
started? The apparatus is very rigid, I can't remove the flask from the ice bath unfortunately.
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