What Is Fischer Esterification

Treatment of a carboxylic acid with an alcohol in the presence of an acid catalyst—most commonly, concentrated sulfuric acid—gives an ester. This method of forming an ester is given the special name Fischer esterification after the German chemist Emil Fischer (1852-1919). As an example of Fischer esterification, treating acetic acid with ethanol in the presence of concentrated sulfuric acid gives ethyl acetate and water  

We study the structure, nomenclature, and reactions of esters in detail in Chapter 14. In the present chapter, we discuss only their preparation from carboxylic acids. 

Acid-catalyzed esterification is reversible, and generally, at equilibrium, the quantities of remaining carboxylic acid and alcohol are appreciable. By controlling the experimental conditions, however, we can use Fischer esterification to prepare esters in high yields. If the alcohol is inexpensive compared with the carboxylic acid, we can use a large excess of the alcohol to drive the equilibrium to the right and achieve a high conversion of carboxylic acid to its ester. 

Here is a structural formula for the ester produced in each 

In a Fischer esterification, each carboxyl group is converted to an ester in which the —OR group originates from the alcohol reagent. 

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