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Recrystallization of Acetylsalicylic Acid

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jny:
In lab, I recovered 2.20g of acetylsalicylic acid (by reacting 2.00g salicylic acid and excess acetic anhydride in presence of sulfuric acid) by means of vacuum filtration. I calculated % yield as so:

0.014 mol salicylic * 180.04g/mol acetylsalicylic = 2.520g acetylsalicylic acid theoretical yield.
(2.20g recovered/2.520g theoretical) * 100 = 87.282% yield.

We performed recrystallization by supersaturating the recovered acetylsalicylic acid in hot ethyl acetate. After cooling, I was able to recover 1.10g of acetylsalicylic acid.

What is the proper approach as to determining the percent yield after recrystallization?

jny:
sorry for double post.. i'm on wireless

movies:
I would report a yield of both pure product and a yield from your recrystallization step.  The yield from the recrystallization step is a good indication of the purity of the first product that you isolated (assuming that the recrystallization procedure is highly efficient) whereas the overall yield of pure product is more indicative of the overall efficiency of the synthetic process on the whole.

You should also report a crude yield, by the way.

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