Synthesis of Benzocaine
Introduction/Aims:
The aim of the current investigation is to investigate the acid-catalysed Fischer esterification mechanism underlying the synthesis of the anaesthetic benzocaine using p-aminobenzoic acid and ethanol in excess. The resulting synthesised compound was subject to IR and melting point analyses in order to determine the identity and indeed the purity of the obtained sample.
Benzocaine exhibits two main components common to the anaesthetic family: (1) an aromatic system usually having directly attached an ester and (2) a one to four unit hydrocarbon chain. The ester group is essential in body detoxification of this substance due to enzymatic cleavage of the ester linkage. Other anaesthetics may also contain a tertiary amine functional group which translates into the compound being soluble in the body.
Stoichiometric Equations:
Reactant table:
The limiting reagent of this reaction is p-aminobenzoic acid. Thus the theoretical yield of benzocaine is expected to be 0.036 mols as a 1:1 ratio exists between and 4-aminobenzoic acid and benzocaine.