Condensation of Acids with Alcohols The Fischer Esterification

Condensation of Acids with Alcohols The Fischer Esterification 961... 

This method is called the Fischer esterification. It s a condensation reaction where the loss of a water molecule accompanies the joining of the alcohol portion to the acid portion. The acid gives up the OH and the alcohol gives up the H to make the water molecule. All steps in the mechanism are reversible (that is, it establishes an equilibrium), so removing the ester as soon as it forms is helpful. Removal of the ester is normally easy since esters typically have lower boiling points than alcohols and carboxylic acids. Figure 12-20 illustrates the mechanism for the acid-catalyzed formation of an ester by the reaction of an alcohol with a Ccirboxylic acid. 

To an organic chemist, the term ester normally means an ester of a carboxylic acid, unless some other kind of ester is specified. Replacing the —OH group of a carboxylic acid with the —OR group of an alcohol gives a carboxylic ester. The following condensation, called the Fischer esterification, shows the relationship between the alcohol and the acid on the left and the ester and water on the right. 

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