Question

In "The Preparation of the Local Anesthetic, Benzocaine, by an Esterification Reaction" experiment

1. Refer to the structure of Procaine in the table in the above introduction, “Local Anesthetics.”
Using 4-aminobenzoic acid, give a reaction equation illustrating how Procaine could be prepared.
2. Which of the two possible amino functional groups in Procaine would be protonated first?
Why?
3. Define reflux or refluxing in your own words

Answer 1

1. Dranw below is the reaction scheme for the formation of procaine starting with 4-aminobenzoic acid and base NaOH.

2. The amino group NEt2 would be protonated first as it is more electron rich in nature and can donate its pair of electron easily. Whereas, the -NH2 group attached to phenyl ring is less electron rich as the lone pair of N is delocalised in benzene ring.

3. Reflux is heating a liquid to its boiling point with a condenser on top, so that the vapors that goes up recondenses back into the solution.