Synthesis And Study For Benzocaine

Benzocaine is an important medicinal intermediate products of Orthoform, Orthocaine and Procaine, and is also one of local anesthetics. The preparation of Benzocaine by esterification and reduction from 4-Nitrobenzoic acid and Ethanol has been intensively studied.First, the synthesis of p-Nitro-ethylbenzoate by three methods.1. p-Nitro-ethylbenzoate was synthesized by conventional heating method, using p-toluene sulfonic acid as catalyst. The reaction time was 2.5h and the yield was 95.1%.2. Synthesis of p-Nitro-ethylbenzoate catalyzed by p-toluene sulfonic acid under microwave irradiation. The radiating time of microwave was 11min, the yield was 96.5%.3. P-Nitro-ethylbenzoate was synthesized from p-Nitrobenzoic acid and Ethyl alcohol using p-toluene sulfonic acid supported on activated carbon under microwave irradiation. The radiating time of microwave was 11min and the yield was 98.2%. The yield of P-Nitro-ethylbenzoate was more than 90% after five recycles.Secondly, iron and ammonium chloride were used for the synthesis of benzocaine from P-Nitro-ethylbenzoate, the yield was 84%.In the paper, effects of molar ratio of alcohol and acid, catalysts, reaction temperature, reaction time on yield of the P-Nitro-ethylbenzoate were studied, while the reduction process was improved. Finally it conclude optimal conditions for the prepare of benzocaine. The structure of product was confirmed by IR,1HNMR, physics analysis etc to be basically consistent with the target product.