Fischer esterification

Fisher esterification (complete name Fischer–Speier esterification) is an organic chemical reaction in which an alcohol reacts with a carboxylic acid in the presence of a strong acid to create an ester and water. This is a coupling reaction. It was first described by the chemists Hermann Emil Fischer and Arthur Speier. This is a dynamic reaction which exists in equilibrium. The chemists object is to manipulate concentration and conditions to drive the reaction towards the desired product before they die of old age. Fisher esterification is slow. It helps not a bit that in reverse, water hydrolyzes an ester to return the alcohol and the carboxylic acid. Both processes coexist, so the task is not easy.

Tips

• Remove one of the products as the reaction proceeds to force the equilibrium in that direction.
• Start with as little water as possible.
• Start with an excess of the alcohol and let Le Chatelier do the driving.
• Wear comfortable shoes.

Examples

A classic example is to distill glacial acetic acid, anhydrous ethanol with a catalytic amount of concentrated sulfuric acid to give ethyl acetate. The resulting distillate can be then be further purified and re-distilled as described by Erowid.

Mechanism

Read about the mechanism [here]

Projects

• Methyl salicylate (Oil of Wintergreen)
• Dimethyl oxalate

References

Relevant Sciencemadness threads

• Fischer esterification equilibrium
• Catalysts for Fischer Esterification
• Making esters without sulfuric acid
• Esterification of Malonic Acid to DiEthyl Malonate
• Thought from "Fisher esterificatioon of ethylene glycol"
• Fisher esterification of citric acid and acetic acid to make this?
• Fisher-Esterification
• Fisher Esterification - Flavoring Chemicals