why is Na/C2H5OH not preferred in the reduction of carboxylic acid to alcohols, despite being used for esters?
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$\begingroup$ You could get deprotonation as a side reaction, because the reagent generates a strong protic base (ethoxide ion). $\endgroup$– Oscar LanziDec 1, 2018 at 10:04
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$\begingroup$ Correct. You get the sodium carboxylate which does not reduce. $\endgroup$– WaylanderDec 1, 2018 at 10:19
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1 Answer
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As the comments point out: the sodium in ethanol generates sodium ethoxide, just as sodium in water generates the hydroxide. The ethoxide ion, acting as a strong base, deprotonates the acid to a salt and thwarts the reduction. Get rid of the easily removed proton by using an ester and you unleash the reduction reaction you want.
answered Dec 1, 2018 at 23:42