In: Chemistry
The Fischer esterification mechanism is examined in the following two questions in the assignment. Part 1 involves MeOH addition to form the key tetrahedral intermediate. Part 2 will involve loss of H2O to form the ester.
Concepts and reason
Fischer esterification:
It is an esterification reaction, in which carboxylic acid changes to ester when it reacts with alcohol in the presence of strong acid.
Fundamentals
The mechanism for Fischer esterification reaction:
1)Abstraction of the proton from an acid by carbonyl oxygen.
The lone pair of carbonyl oxygen in carboxylic acid abstracts proton from an acid by cleaving chlorine. This abstraction of hydrogen produces a positive charge on oxygen.
The lone pair electron of oxygen in alcohol attacks the carbonyl carbon and stabilizes the positive charge on carbonyl oxygen by resonance. The carbonyl attack by an alcoholic oxygen creates a positive charge on alcoholic oxygen.
The intermediate is formed by the abstraction of proton by chloride ion and stabilize the positive charge on alcoholic oxygen.