BENZOCAINE,LIDOCAINE,NOVOCAINE,PROCAINE

Photocatalytic Properties of Benzocaine

Li, Adela Jing, et al. Journal of hazardous materials, 2017, 337, 115-125.

Ethyl 4-aminobenzoate (Et-PABA) is a water-soluble derivative of 4-aminobenzoic acid (PABA), commonly known as benzocaine. Et-PABA can be used as a replacement for 4-aminobenzoic acid (PABA) in sunscreens and anesthetic creams. The transformation products (TP) and environmental fate of Et-PABA were evaluated through cumulative potency and photocatalytic profile analyses.
Photoconversion process of Et-PABA
It is proposed that photocatalysis induces transformation pathways of dehydroxylation, demethylation and molecular rearrangement:
· It is inferred that Et-PABA was firstly transformed to TP-182 and TP-198 by (di)hydroxylation.
· A further demethylation of TP-152B and TP-168 led to the formation of PABA and TP-154.
· Under UV-C irradiation, PABA is suggested to form TP-154 by hydroxylation.
· Continuously, PABA and TP-154 produced TP-120 and TP-136, respectively, by dehydroxylation and molecular rearrangement. The pathway ultimately produced TP-152A, which was proposed to be a TP of TP-136 or TP-184.