Esterification

Why is a carboxylic acid not reactive toward nucleophiles under neutral or basic conditions and what is the specific issue with the leaving group?

the hydroxyl group (OH) of a carboxylic acid is a bad leaving group. hydroxide ion (OH-) is a strong base and is not a good nucleophile

What are 2 critical steps required to activate a carboxylic acid for nucleophilic acyl substitutions. include the role of an acid catalyst

• Protonation- an acid catalyst protonates the carboxylic acid

• Nucleophilic attack and reformation: a nucleophile attacks and water reprotonates

Write the mechanism for esterification from a carboxylic acid and an alcohol.

What are two specific ways to shift the equilibrium to favour ester formation.

• Use an excess amount of one reactant (the acid)

• remove a byproduct from the reaction mixture

Rank the following carboxylic acid derivatives from most to least reactive toward nucleophilic acyl substitutions: Ester, Acid Chloride, carboxylic acid, amide

Acid chloride > carboxylic acid (when activated) > ester > amide

What key reagents were used in this experiment and list their purpose.

• a carboxylic acid

• An alcohol

• Sulphuric acid- the catalyst

• NaHCO3 (sodium bicarbonate)- neutralisation