How would you recrystallize acetanilide using ethanol and hexanes? I know this compound is not soluble with the hexanes solvent. But, where would I include ethanol in the procedure? Would I heat up the ethanol and then add hexanes dropwise?
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1$\begingroup$ Comment: Why ethanol/hexanes? It may depend on the history of your sample, but why would not do a mixture of water/ethanol do the job which I imagine to find in a reference like the red Vogel book (practical organic chemistry), or in Perrin's about how to purify lab chemicals? $\endgroup$– ButtonwoodMar 13, 2021 at 7:55
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$\begingroup$ If you have small amount to crystalize water is the best solvent (Solubility at $\pu{0 ^\circ C}$: $\pu{0.53 g}$/$\pu{100 mL}$; and solubility at $\pu{100 ^\circ C}$: $\pu{5.5 g}$/$\pu{100 mL}$). $\endgroup$– Mathew MahindaratneMar 14, 2021 at 18:34
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1 Answer
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There are two ways to do this:
Firstly you could dissolve your acetanilide in hot ethanol and add hexane dropwise (keeping the solution hot) until you detect some cloudiness then leave it to cool.
Secondly suspend your acetanilide in hot hexane and add ethanol dropwise (keeping the solution hot) until it dissolves then leave it to cool.
Scratching the interior surface of the flask can help creating nucleation sites, or the addition of a seed crystal of pure acetanilide if you have one.