Kinetic study for synthesizing dibenzyl phthalate via solid-liquid phase-transfer catalysis

In the present study, the kinetics for synthesizing dibenzyl phthalate via solid-liquid phase-transfer catalysis under anhydrous conditions was invest igated. The esterification of benzyl bromide and solid reactant dipotassium phthalate was carried out in a stirred batch reactor. The behavior of the active intermediate in solid-liquid phases was explored to understand its c atalytic characteristics. The effects of agitation speeds, concentration of reactants, phase-transfer catalysts, organic solvents, amounts of catalyst s used, and reaction temperatures were all investigated. A kinetic model de scribing the reactions in a solid-liquid system was also proposed. From the experimental results, the reaction rate increases with increasing agitatio n speed, polarity of organic solvent, and temperature even without adding w ater and can be described by the pseudo-second-order kinetics. The reaction rate was extremely slow without using catalysts even at a higher temperatu re. The apparent rate constants as well as the activation energies for vari ous phase-transfer catalysts were obtained. The present study provides an i nsight on the catalytic behaviors of solid-liquid phase-transfer catalysis.