Acetone and chloroform
Staffan Friberg
you disagree strongly then please press "N" now.
In the book "Advanced Practical Organic Chemistry" one can read that adding
chloroform to acetone can result in an explosion. It does not, however, tell
why this is.
My lecturer said that he had seen papers reporting of accidents but he could
give no explanation.
Is there anyone out there who knows what happens or can someone give me a
pointer where to look for the answer.
Thanks!
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Trí nithe is géire ar bith:
dealg múnlaigh, fiacal con agus focal amadáin.
Richard C. Yeh
> In the book "Advanced Practical Organic Chemistry" one can read that adding
> chloroform to acetone can result in an explosion. It does not, however, tell
> why this is.
> Is there anyone out there who knows what happens or can someone give me a
> pointer where to look for the answer.
Merck Index claims that acetone (CH3COCH3) is miscible in chloroform (CHCl3),
and that acetone is utilized in the production of chloroform.
acetone is flammable;
chloroform is non-flammable.
Sincerely,
--
Richard Cheng-I Yeh <rc...@cco.caltech.edu> _______
MSC #932 |
Caltech |__
Pasadena CA 91126-0001 | |
__|_|____
I assume responsibility for all of my actions.
Staffan Friberg
> In article <staff...@rabbit.augs.se> st...@rabbit.augs.se (Staffan Friberg) writes:
>
> > In the book "Advanced Practical Organic Chemistry" one can read that adding
> > chloroform to acetone can result in an explosion. It does not, however, tell
> > why this is.
>
> > Is there anyone out there who knows what happens or can someone give me a
> > pointer where to look for the answer.
>
>
> Merck Index claims that acetone (CH3COCH3) is miscible in chloroform (CHCl3),
> and that acetone is utilized in the production of chloroform.
It does? That's odd. I'll have to check the sources of those reports again.
Still, the book says what it says.
> acetone is flammable;
> chloroform is non-flammable.
Yes, I knew that. Obviously something else should be formed. The question is
what.
Greg Cook
> In article <RCYEH.93N...@chamber.cco.caltech.edu> rc...@chamber.cco.caltech.edu (Richard C. Yeh) writes:
>
>> In article <staff...@rabbit.augs.se> st...@rabbit.augs.se (Staffan Friberg) writes:
>>
>> > In the book "Advanced Practical Organic Chemistry" one can read that adding
>> > chloroform to acetone can result in an explosion. It does not, however, tell
>> > why this is.
>
> what.
Hmm, I routinely mix acetone and chloroform without problems. Chloroform
is stabalized with some ethanol, without the ethanol, chloroform can
decompose and form phosgene which may be the culprit here.
>
___ Gregory R. Cook | INTERNET: gc...@horus.cem.msu.edu
<*,*> Department of Chemistry | cook...@student.msu.edu
[`-'] Michigan State University | co...@cemvax.cem.msu.edu
-"-"- East Lansing, MI 48824 | BITNET: cook@MSUCEM
Leslie J Harrison
: > In the book "Advanced Practical Organic Chemistry" one can read that adding
: > chloroform to acetone can result in an explosion. It does not, however, tell
: > why this is.
: > Is there anyone out there who knows what happens or can someone give me a
: > pointer where to look for the answer.
This perhaps refers to the potential hazard present when chloroform and
acetone are disposed of in the same waste solvent container. Add some base
to the mixture and legend claims that an explosion can (and will) occur.
Dichlorocarbene gets the blame. I have never seen this happen,
(un)fortunately.
Leslie
--
Leslie J Harrison Internet: ch...@leonis.nus.sg
Dept of Chemistry
National University of Singapore Tel: (65) 772 2687
Singapore 0511 Fax: (65) 779 1691
Staffan Friberg
> Hmm, I routinely mix acetone and chloroform without problems. Chloroform
> is stabalized with some ethanol, without the ethanol, chloroform can
> decompose and form phosgene which may be the culprit here.
Is Phosgene explosive? I guess it could be formed.
Another suggestion I have recieved speaks about formation of:
2-trichloromethyl-2-propanol. This is obviously an exothermic reaction.
Michael Alan Roberts
>
>> Hmm, I routinely mix acetone and chloroform without problems. Chloroform
>> is stabalized with some ethanol, without the ethanol, chloroform can
>> decompose and form phosgene which may be the culprit here.
>
>Is Phosgene explosive? I guess it could be formed.
Can you explain how this happens? I don't see how you can get a reaction
to occur between acetone (CH3COCH3) and chloroform (CHCl3).
>Another suggestion I have recieved speaks about formation of:
>2-trichloromethyl-2-propanol. This is obviously an exothermic reaction.
This compound is unlikely to be a product, unless some other condition
is described that I missed (I joined this thread late).
>Trí nithe is géire ar bith:
>dealg múnlaigh, fiacal con agus focal amadáin.
Please tell me what this means. I'm curious. Also please tell me the
language that you are quoting.
Cheers,
--
Michael Roberts | "...Noone here gets out alive..."
rob...@ucunix.san.uc.edu | -Jim Morrison
Kevin Sutton
>From: rob...@ucunix.san.uc.edu (Michael Alan Roberts)
>Subject: Re: Acetone and chloroform
>Date: 25 Nov 1993 20:43:36 -0500
>In article <staff...@rabbit.augs.se> st...@rabbit.augs.se (Staffan Friberg) writes:
>>In article <2cl7s3$14...@msuinfo.cl.msu.edu> gc...@horus.cem.msu.EDU (Greg Cook) writes:
>>
>>> Hmm, I routinely mix acetone and chloroform without problems. Chloroform
>>> is stabalized with some ethanol, without the ethanol, chloroform can
>>> decompose and form phosgene which may be the culprit here.
>>
>>Is Phosgene explosive? I guess it could be formed.
The culprit is not phosgene but dichlorocarbene (:CCl2). As anyone who has
done a bit of radical chemistry will know, these beasties are rather
reactive and the carbonyl group on the acetone makes a 'dandy' target. The
reason it goes faster in alkali is that the chloroform proton is acidic
(because of the inductive effect of the chlorine atoms) and is easily
removed in base to form (eventually) the carbene.
You can get away with mixing chloroform and acetone (waste or otherwise) in
the absence of base but it isn't a good idea since Murphys law states that
if you do some idiot will come along and put some alkali in the same
container. Most sensible people keep the two solvents in separate containers!
Cheers
Kevin
Murphy's First Law of Laboratory Practise:-
"Hot glassware looks just like cold glassware"
Kevin Sutton Internet : sut...@Lincoln.cri.nz
Crop & Food Research Limited, Private Bag 4704,
Christchurch, NEW ZEALAND
Greg Cook
>
> Can you explain how this happens? I don't see how you can get a reaction
> to occur between acetone (CH3COCH3) and chloroform (CHCl3).
>
>>Another suggestion I have recieved speaks about formation of:
>>2-trichloromethyl-2-propanol. This is obviously an exothermic reaction.
>
> This compound is unlikely to be a product, unless some other condition
> is described that I missed (I joined this thread late).
If the culprit is dichlorocarbene, then this could easily be the
product:
CHCl3 + base ----> :CCl2
:CCl2 + CH3-CO-CH3 -------> CH3--C--CH3
/ \
Cl2C---O
Then the epoxide could be opened up with Cl- to give the product
mentioned above.
Is this very exothermic? I'm too lazy to calculate the energies.
Staffan Friberg
> >Is Phosgene explosive? I guess it could be formed.
> Can you explain how this happens? I don't see how you can get a reaction
> to occur between acetone (CH3COCH3) and chloroform (CHCl3).
About the phosgene, I really don't know. When I first read it I thought that
I knew a way but after a moment I realised that I made a mistake.
That's posting without thinking. :-)
> >Another suggestion I have recieved speaks about formation of:
> >2-trichloromethyl-2-propanol. This is obviously an exothermic reaction.
> This compound is unlikely to be a product, unless some other condition
> is described that I missed (I joined this thread late).
Well, you have to have some kind of base present. Chloroform can decompose to
(CCl3)- if a base takes the hydrogen. The ion can then attack the carbonyl
cabon in acetone. If no acetone is present this is a way of forming
dichlorocarbene.
The problem is that this should happen all the time and not just once in a
while.
> >Trí nithe is géire ar bith:
> >dealg múnlaigh, fiacal con agus focal amadáin.
>
> Please tell me what this means. I'm curious. Also please tell me the
> language that you are quoting.
It's irish and it means (roughly):
The three sharpest things in the world:
The point of a saying, the tooth of a hound and the word of a fool.
--
//
//
++++++++++++++++++++++++++++++++++++++++++++++++++++++ \\ // AMIGA +++
+ Staffan Friberg + EMail: \X/ +
+ Undergraduate student Chemistry + +
+ Linköping University + InterNet: st...@rabbit.augs.se +
+ Sweden + FidoNet: 2:204/404.2 or +
+ + 2:204/418.9 +
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Sheila Marshman
>In article <RCYEH.93N...@chamber.cco.caltech.edu>
> rc...@chamber.cco.caltech.edu (Richard C. Yeh) writes:
>
>> In article <staff...@rabbit.augs.se> st...@rabbit.augs.se (Staffan Friberg)
> writes:
>>
>> > In the book "Advanced Practical Organic Chemistry" one can read that
> adding
>> > chloroform to acetone can result in an explosion. It does not, however,
> tell
>> > why this is.
>>
>> > Is there anyone out there who knows what happens or can someone give me a
>> > pointer where to look for the answer.
>>
There is a full description of this reaction in a book by Les Bretherick:
Hazards in the Chemical Laboratory ( I think ).
This was originally published in the late 1970s, but has been updated
since then.
I know of several occasions when acetone and chloroform were mixed in
test tubes which became uncomfortably warm, presumably due to trace amounts
of base being present. At least one explosion was reported about 1979 in
various safety bulletins which was directly attributable to mixing
acetone and chloroform with base.
--
Sheila Marshman
Eric W Anderson
Note that you don't need a chemical reaction to occur for acetone and
chloroform mixtures to become warm. Each pure solvent is a moderately polar
but non-hydrogen-bonding solvent. Together, they form hydrogen bonds between
the proton of CHCl3 and the oxygen on the acetone. Heat is evolved.
This doesn't mean that chemical reactions can't also happen, especially in
the presence of impurities. For example, my _Hazardous Chemicals Desk
Reference_, Sax & Lewis says chloroform "reacts violently" with acetone +
base.
--
----------------------------------------------------------------------
Eric W. Anderson | ewan...@mit.edu
MIT Chemical Engineering Dept. |
Cambridge MA 02139 | (617) 253-2369