Reaction of Carboxylic Acids with Alcohols

Carboxylic acids react with alcohols, in the presence of an acid catalyst, to form esters. This type of reaction is called esterification.

The diagram below shows the bridging oxygen for the ester comes from the alcohol. This was determined by the American chemists Irving Roberts and Harold C. Urey in 1938, using a technique called isotopic labelling. This method involves preparing an alcohol with the oxygen isotope ¹⁸O for reaction with a carboxylic acid. Analysis of the reaction products in a mass spectrometer shows that all the ¹⁸O is in the ester and not in the water. Therefore, all the bridging oxygen must come from the alcohol.

 

 

Methanoic Acid Reaction with Ethanol

methanoic acid + ethanol ethyl methanoate + water

HCOOH + C₂H₅OH HCOOC₂H₅ + H₂O

 

Ethanoic Acid Reaction with Ethanol

ethanoic acid + ethanol ethyl ethanoate + water

CH₃COOH + C₂H₅OH CH₃COOC₂H₅ + H₂O

 

Propanoic Acid Reaction with Ethanol

propanoic acid + ethanol ethyl propanoate + water

C₂H₅COOH + C₂H₅OH C₂H₅COOC₂H₅ + H₂O

 

Butanoic Acid Reaction with Ethanol

butanoic acid + ethanol ethyl butanoate + water

C₃H₇COOH + C₂H₅OH C₃H₇COOC₂H₅ + H₂O

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