madmaxman
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recrystalized from cold acetone terminology
After reading some old chem texts I had a question, it mentioned that the crude product was "recrystalized from cold acetone". No volumes were given
or additional information.
Does this mean that the crude compound is dissolved in acetone (minimal amount for dissolving?) and then the acetone cooled and filtered to get the
crystal product?
I guess it could also mean taking up the crude product with cold acetone and then evaporating?
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LearnedAmateur
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To me, this reads that you dissolve it in the minimum amount of cold acetone and let it evaporate. Although it is strange, usually you’d
recrystallise from hot and scrape the sides of the container when the solvent is at room temperature or cooled in some other fashion in order to
precipitate the more pure product.
What is the compound in question? Maybe hot acetone would facilitate decomposition hence it needs to be cooled? Or the byproducts/impurities have
similar dissolution properties?
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
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DraconicAcid
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The former. Dissolve it in a minimum of acetone, and cool it to get crystals. I suspect that it might deteriorate when heated, otherwise, they would
have just said "acetone".
If your acetone is dry, of course, you can cool it by a lot. Put it in the freezer, put it outside overnight in January in Edmonton, put it in dry
ice.....
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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diddi
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I tend to agree with the stability of the product being compromised at temperature. Acetone is marvelous for working at low temps. I have used it to
run reactions at -50C and below for the price of a bit of dry ice. Great.
Beginning construction of periodic table display
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aga
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It might be a little bit helpful to know what the 'crude product' is, maybe ?
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XeonTheMGPony
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or here in Sask, 2013 winter we hit -62, aut to crystallize the O2 out of it!
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Reboot
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Unless something unusual is at work, I assume it's a simple, classic recrystallization. Just enough hot acetone is added to the product to dissolve
it, then the solution is chilled to precipitate out the product by reducing its solubility.
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DraconicAcid
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Quote: Originally posted by Reboot  | Unless something unusual is at work, I assume it's a simple, classic recrystallization. Just enough hot acetone is added to the product to dissolve
it, then the solution is chilled to precipitate out the product by reducing its solubility.
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If that was the case, they would just say, "recrystallized from acetone".
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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zed
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What is the product? That should clarify things.
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