The chemical equation for the synthesis of benzocaine ethyl p-aminobenzoate from p-aminobenzoic acid and ethanol is as follows:p-aminobenzoic acid + ethanol benzocaine + waterTo obtain a high yield of benzocaine, the reaction is typically carried out using a Fischer esterification process. The optimal reaction conditions and procedures are as follows:1. Acid catalyst: Use a strong acid catalyst, such as concentrated sulfuric acid H2SO4 or hydrochloric acid HCl , to promote the esterification reaction.2. Molar ratio: Maintain a molar ratio of p-aminobenzoic acid to ethanol of 1:1. Excess ethanol can be used to drive the reaction to completion, but it may also lead to the formation of side products.3. Temperature: The reaction is typically carried out at a temperature of 80-100C. Higher temperatures may cause the reaction to proceed faster, but they can also lead to the formation of side products and decomposition of the reactants.4. Reaction time: The reaction should be allowed to proceed for 2-4 hours to ensure a high yield of benzocaine. The progress of the reaction can be monitored using thin-layer chromatography TLC or other analytical techniques.5. Extraction and purification: After the reaction is complete, the mixture should be cooled to room temperature and diluted with water. The benzocaine product can be extracted using an organic solvent, such as ethyl acetate or dichloromethane. The organic layer can then be washed with water and brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product can be purified using recrystallization from a suitable solvent, such as ethanol or methanol.By following these optimal reaction conditions and procedures, a high yield of benzocaine can be obtained from p-aminobenzoic acid and ethanol.