An Efficient Two-Phase Reaction Process for the Production of Ethyl Acetate

Most of the commercial processes for ethyl acetate (EAc) production are via liquid-phase esterification. Owing to the thermodynamics limitation, the overall yield of EAc is typically within 67% with equimolar reactants. Consequently, 30% of unreacted reactants are with azeotropic byproducts of ethanol-water, ethanol-EAc, and ethanol-water-EAc. To separate these impurities is laborious and energy-consuming. In this study, the one-pass ethanol conversion was successfully improved from 67 to 85 mol %, while the ethanol concentration was decreased from 14 to 6.5 wt %. One of the critical parameters is the reaction temperature. It was kept between the liquid-phase and vapor-phase operation regimes, at which some of the reacting compositions were in the vapor phase in the reaction condition. The initial reaction stage in the liquid phase has the advantages of smaller reactor size and more efficient contact with the catalysts. Because equilibrium had been reached in the final vapor phase, a higher conversion of ethanol was obtained as a result of constraints by reaction equilibrium. Consequently, both the equilibrium constraints for the liquid-phase regime and larger reactor volume requirements for the vapor-phase reaction have been overcome. In addition, the solid acid catalysts used in this process have a low impact on the environment and cause no corrosion to the reactor wall. The life test of the catalyst has been carried out, demonstrating no decay for 570 h.