Phenyl benzoate synthesis from benzoyl chloride and phenol was investigated in three kinds of reactors. When polyethylene glycol (average molecular weight 3000) was used as a phase transfer catalyst and toluene as an organic solvent, a third liquid phase that mainly consisted of the catalyst was formed when KOH concentration in the aqueous phase and the concentration of phenol were increased. However, the selectivity of phenyl benzoate was less than 0.6 in a well-mixed batch reactor because benzoyl chloride and phenyl benzoate both underwent hydrolysis. The selectivity could be raised above 0.9 by changing phenol and KOH concentrations in a phase-separable batch reactor in which direct contact between the organic and the aqueous phases could be prevented by the third liquid phase. A new type of phase separable continuous stirred tank reactor (CSTR) in which benzoyl chloride and phenol were separately supplied to the organic and the aqueous phases, respectively, was devised to obtain the same high selectivity as the phase separable batch reactor.