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Why does base aspirin hydrolysis work better than acid aspirin hydrolysis? I conducted an experiment and found that there was greater Salicylic Acid yield for the one I added base compared to the one I added acid. Why is this so?

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    $\begingroup$ In what solvent system was this run? $\endgroup$
    – Waylander
    Nov 21, 2022 at 15:18
  • $\begingroup$ I believe ethanol and water $\endgroup$
    – fdsaa
    Nov 21, 2022 at 15:23
  • $\begingroup$ Possibly aspirin is less soluble in acidic EtOH/water than in basic EtOH/water. $\endgroup$
    – Waylander
    Nov 21, 2022 at 16:41
  • $\begingroup$ Does this answer your question? $\endgroup$ Nov 21, 2022 at 18:10
  • $\begingroup$ Also, the mechanism given in this article explains why base is better catalysis. $\endgroup$ Nov 21, 2022 at 18:18

2 Answers 2

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Base (OH-) is the perfect nucleophile for ester hydrolysis of acetylsalicylic acid.

Acid pronation of the ester carboxyl group, which is further conjugated with benzene ring, and the far weaker OH2 nucleophile, will not work as well.

Base (and heat) hydrolysis is preferred, leaving carboxylate and OH groups.

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Simple Le Chatlier's rule. Since the hydrolysis produces acid, base catalysts will remove the products (the acid), shifting the reaction.

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