Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: chunkmartinez on June 08, 2007, 03:33:38 PM
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can anyone explain how an "acetone wash" works. I have heard it, but never had an explanation on it. thanks. ???
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In what context did you hear it?
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That could mean a lot of things.
For example, using acetone to dry containers or devices that you used with water. This may be referred to as "washing."
Sometimes when you clean out certain devices or instruments (i.e. cuvettes) for spectroscopic studies, for example, you use acetone or some other highly evaporative chemical to help remove solvent particles.
Those are just two examples. It's kind of hard to define "acetone washing" without providing examples.
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ok, what i meant is purifying with acetone. For example caffeine.HCl powder, in which has other things, non-desireable to consume. isn't acetone both favorable in solubility to both polar and non-polar things. i read it has a dielectric constant of 20.7 .
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I don't think we're understanding you clearly. Can you narrow it down a bit?
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ok, it works like this.
you have a mixture of solids. all of the chemicals present in your mixture will dissolve in acetone in a diferent ammount. some will dissolve completely, while some practically wont dissolve at all.
if you "wash" your mixture of solids with acetone, you'll end up with two products. on your funnel or similar part of your setup you'll have the unsoluble solids that are left over.
on the acetone colected you'll have all the chemicals that dissolved in acetone.
depending on exactly what you have on your mixture, you can look up the solubilities and calculate wether this is useful for your purpouses, and in that case where should you look for your desired product: on the acetone or on the funnel.
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well so, aren't most things soluble in acetone??
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that's completely irrelevant.
it doesnt matter what "most things" do... its all about what do the things YOU have on your mixture do...
if you were to go by the sole principle that "most things dissolve in acetone", then the whole process of an acetone wash would be useless, since it should dissolve everything.
guess what: it doesnt.
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well atleast isn't acetone slopy for purifying? the way i believe it is, ethanol, and acetone have a similar dipolar constant, in which lies between the point of solubility of both polar and non-polar subatstences, in which would mean it is not verry effective to dissolve only certain things.
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obviously it is not the gold standard for purification, but it would no doubt be a useful start.
as mentioned above, it doesn't matter how many things in chemistry are soluble in acetone, only that the relative solubilities of the things you are separating is different. for example, sodium chloride and caffeine would be very easily separated by this method
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^^because sodium cloride is not soluble in ethanol???
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^^because sodium cloride is not soluble in ethanol???
exactly