Etherification of halo-ester by phase-transfer catalysis in solid-liquid system

摘要

In the present study, the kinetics for the etherification of ethyl 2-bromoisobutyrate with poassum 4-benzyloxyphenoxide in the presence of potassium iodide via solid-liquid phase-transfer catalysis (SLPTC)was investigated. The reaction was carried out in a stirred batch reactor. The effects of agitation speeds, concentration of reactants, ohase-transfer catalysts, organic solvents, amounts of catalysts, and reaction temperatures were performed to find the appropriate conditions.Using the present reaction system, the hydrolysis side reaction of ether-ester was prevented. A kinetic model taking into account the deactivation behavior of the catalyst was proposed to describe the overall reaction successfully. The pseudo first-order kinetics with the deactivation function was employed to estimate the initial apparent rate constants and the deactivation constants empirically.The activation energies for catalysts tetra-n-buty lammonium bromide and tetra-n-phosphonium bromide as well as the behavior ofco-catalyst potassium iodide in solid-liquid phase-transfer catalysis were obtained.