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.

carboxylic acid + alcohol acid catalyst ester + water

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 acid catalyst ethyl methanoate + water

HCOOH + C2H5OH acid catalyst HCOOC2H5 + H2O



Ethanoic Acid Reaction with Ethanol

ethanoic acid + ethanol acid catalyst ethyl ethanoate + water

CH3COOH + C2H5OH acid catalyst CH3COOC2H5 + H2O



Propanoic Acid Reaction with Ethanol

propanoic acid + ethanol acid catalyst ethyl propanoate + water

C2H5COOH + C2H5OH acid catalyst C2H5COOC2H5 + H2O



Butanoic Acid Reaction with Ethanol

butanoic acid + ethanol acid catalyst ethyl butanoate + water

C3H7COOH + C2H5OH acid catalyst C3H7COOC2H5 + H2O