Benzocaine Ir Analysis

Benzocaine is a topical anesthetic commonly used to relieve pain or discomfort . There are many brands of benzocaine and it is the active ingredient in various over-the-counter analgesic ointments . Benzocaine is the ethyl ester of paraaminobenzoic acid and as an ester it can be classified by Fischer esterification. Fischer esterification reactions typically include a carboxylic acid and alcohol as well as a dehydrating agent . Since esterification reactions are slow, a catalyst is required. The addition of the catalyst maximizes the yield of product (benzocaine) from the esterification since the reaction is reversible which means it tends to result in a low yield of product. For the synthesis of the benzocaine in this experiment, Fischer
Despite this, an IR analysis of the benzocaine compound seems to differ from this conclusion. Upon a determination of the functional groups from the structure of benzocaine, the peaks from the IR were easily identified. All peaks were identified to be functional groups belonging to benzocaine. No starting materials were identified from the IR. There is no doubt that starting materials are nevertheless present with the product but they do not show up in the IR. If carboxylic acid were present, there would be a broad O-H peak around 3600-3200 cm-1 but instead there is a peak at 3339.63 cm-1 and 3419.74 cm-1 indicating N-H functional groups; the two peaks indicate a primary amine group. A peak around 3222.39 cm-1 indicates the C-H group from the benzene ring of benzocaine while the peak at 2981.93 cm-1 suggests the C-H methyl group on the structure as well; a peak at 1679.91 cm-1 indicates the C=O from the carbonyl group. The critical observation from the IR analysis is the loss of the carbonyl group and the gain of the N-H