23676-09-7

64-67-5

99-96-7

23676-09-7

Example I: 15 g (0.108 mol) of p-hydroxybenzoic acid and 54.4 g (0.353 mol) of diethyl sulfate were added to a glass flask containing 75 mL of xylene. The reaction mixture was heated to 90°C. The pH was monitored using a calibrated pH electrode submerged in the reaction mixture. A 35% aqueous NaOH solution [prepared by dissolving 13.6 g (0.326 mol) of NaOH flakes in 25 mL of water] was slowly added dropwise over a period of 90 min under stirring conditions to maintain the pH of the reaction system in the range of 8-10. After the NaOH solution was added dropwise, stirring of the reaction mixture was continued for 15 min. Subsequently, the reaction mixture was cooled to room temperature and 75 mL of water was added. The upper organic phase (containing the target product ethyl p-ethoxybenzoate) was separated from the lower aqueous phase, and the organic phase was washed sequentially with 75 mL of 2% NaOH aqueous solution and 75 mL of water. Finally, the solvent was removed by evaporation to give 20.5 g (97.6% yield) of ethyl p-ethoxybenzoate, which was analyzed by HPLC for 98.6% purity.