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Solubility of chloroform and acetone

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If I had a mixture of chloroform, acetone and water, which solvent would the acetone dissolve in? The chloroform and water would separate. I know that acetone is miscible in water, but it's also soluble in chloroform.

 

Thanks for any help

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If I had a mixture of chloroform' date=' acetone and water, which solvent would the acetone dissolve in? The chloroform and water would separate. I know that acetone is miscible in water, but it's also soluble in chloroform.

 

Thanks for any help[/quote']

 

The chloroform will dissolve in the acetone simply because the chloroform is much more soluble in it :)

 

Cheers,

 

Ryan Jones

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Ryan, I think you misread the question. Acetone and water completely mix with each other in any ratio.

 

If you have a mix of chloroform, acetone and water, then a fairly complicated situation arises from that. Chloroform also is somewhat soluble in water. So, what the precise outcome is, depends on the ratio of the chemicals.

 

But now a practical situation:

Suppose you have 10 ml of chloroform, 50 ml of water and 10 ml of acetone and you shake very well. Then two layers are formed, with chloroform at the bottom and water above. The acetone will partly dissolve in the water and partly in the chloroform. Which part dissolves in the water and which in the chloroform is hard to say beforehand, but the amount of acetone will not be negligable in any of the other solvents.

 

The aqueous layer also will contain some chloroform and the chloroform layer also will contain some water.

 

When also an ionic compound (e.g. a salt, or a soluble hydroxide) is added to the water, then the solubility of acetone in the aqueous layer decreases (try adding acetone to a concentrated solution of NaOH, then you'll see that two layers are formed) and more of it dissolves in the chloroform layer.

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It is not in general a good idea to mix chloroform and acetone. The reason laboratories have a chlorinated solvent waste and a non chlorinated solvent waste is precisely to stop people mixing these two solvents. In the presence of a base it is an explosive mixture

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From where do you have that info? I've done that experiment quite a few times. Mixing acetone, chloroform and a base (e.g. NaOH or KOH) is a well-known way of making chlorobutanol (a.k.a. chlorbutol), a certain drug with a strange but quite pleasant and attracting sweet/mint odor, which makes you feel drunk. I only breathed the vapor of the drug, I did not eat some of the white solid (eating a few 100 mg of that stuff is the supposed route of intake). The reaction is fairly exothermic, but certainly not explosive. With a mix of room temperature 50% acetone, 50% chloroform, to which an equal volume of a solution of NaOH in ethanol is added, the liquid becomes quite warm (I estimate 50C or so), but not so hot, that I could not bear the effect on my skin anymore.

 

Of course, when someone mixes hundreds of ml of acetone with similar amounts of chloroform and adds a strong base, then you may have bad surprises.

 

The reaction is specific for chloroform. I also tried with trichloroethene and dichloromethane. These do not react with acetone in the presence of NaOH. The NaOH is a catalyst in the reaction with chloroform, it is not used up. Apparently, it forms a CCl3(-) ion, itself being converted to water. The CCl3(-) ion in turn attacks the acetone to form CH3C(O-)(CCl3)CH3 and the O- reacts with water (from the OH(-) and the CHCl3) to form OH(-). The net result is CH3C(OH)(CCl3)CH3.

 

If someone does this experiment, please do not ingest the stuff you make! That would be a most stupid thing to do. You have a severe risk of poisoning yourself with chloroform! It is, however, quite interesting to smell this compound, it has a really fancy odour and a strange 'refreshing' and 'opening' effect on the nose and throat! Be prepared, however that this stuff is not something to play with lightly. It makes you feel like you've drunk too much and I would not go out and drive a car anymore if I had sniffed some of the vapor.

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Of course in a lab the chlorinated and other solvents need to be collected separately. That is a good practice. Over there, quantities can also be quite large. However, at my home experiment, I only used a few ml total of liquids.

 

The MSDS-info and environmental info from many sites frequently give the worst case scenario and if you read those things then everything is explosive, poisonous and flammable to an extreme extent. There are risks involved in chemistry, but frequently these risks are exaggerated, especially in official documents on safety, such as MSDS's and university safety precautions.

 

In fact, I tried many incompatibilities from MSDS's by mixing incompatibles on-purpose in small quantities. In 9 out of 10 cases, nothing happens at all when the so-called incompatibles are mixed. Usually a lot of other conditions must be fulfilled before something really happens (such as with actone/chloroform: alkali must be present) and then usually, the thing which happens only is a pale shadow of what is described in the document. Where the document mentions explosion or fire, I observe some increase of temperature...

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Woelen - I agree a few mls is not a danger

 

Collection of chlorinated and non chlorinated solvents separately has been going on for decades. This predates any modern disposal and environmental concerns. It was introduced as good labratory practice to prevent explosions.

 

We do not seem to have gotten off to friendly start. I do in actual fact admire your chemistry knowledge and I don't doubt you are a competent electronic engineer, but I have seen far too many silly and serious accidents not to point out what most practising chemists know

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The reference

http://www.southalabama.edu/environm...pendic2003.DOC

is a laugh, it is :-

 

Inaccurate (e.g. mixing sodium hydroxide and water does not result in combustion), incomplete and very ambiguous (e.g. acetaldehyde + acetic acid = explosion, acetic acid + acetaldehyde = increased temperature!!!). Also, if you were using dimethyl sulphate the last thing that you should be concerned about is the violent reaction with ammonium hydroxide. DMS is extremely dangerous, one drop on the skin can kill; ammonium hydroxide should always be within arms reach for de-contamination purposes.

 

It was common practise at my university to use 50:50 acetone:chloroform for chromatographical analysis. Looking back this was a dangerous practice since the eluent was disposed of along with all of the other liquid waste chemicals.

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So. how do you reckon I would get a chloroform layer witout any acetone in it? Cheers ears

 

On topic again:

If you have chloroform and water, and you dump acetone in it, the acetone will go into both water and chloroform, but in different concentrations.

 

So, how to get it out again? You can't. At least, not by (lab)extraction.

After the acetone enters the chloroform, it's not coming out that easy. Mixing three chemicals that have a phase split (that form 2 liquids) generally means you end up with 2 liquid phases, both containing all 3 chemicals. The reason why it's used in separations is that the concentrations in the 2 phases are different.

 

Very often, the second step after extraction is a distillation. I haven't looked at the chloroform acetone boiling points, but I wouldn't be surprised if it's very difficult to separate (they both are very volatile).

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The reference

http://www.southalab....pendic2003.DOC

is a laugh, it is :-

 

Inaccurate (e.g. mixing sodium hydroxide and water does not result in combustion), incomplete and very ambiguous (e.g. acetaldehyde + acetic acid = explosion, acetic acid + acetaldehyde = increased temperature!!!). Also, if you were using dimethyl sulphate the last thing that you should be concerned about is the violent reaction with ammonium hydroxide. DMS is extremely dangerous, one drop on the skin can kill; ammonium hydroxide should always be within arms reach for de-contamination purposes.

 

It was common practise at my university to use 50:50 acetone:chloroform for chromatographical analysis. Looking back this was a dangerous practice since the eluent was disposed of along with all of the other liquid waste chemicals.

 

mmm.. I don´t think it´s so ambigous.. when neutralizing acids with water... it´s not the same to pour water in acid, than acid in water.. you don´t get the same reaction.. don´t u?

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