11. Interfacial Mechanism and Kinetics of Phase-Transfer Catalysis

the catalyst is asolid phase, which reactor type should be properly used in this reactionsystem is not clear.The substitution reaction of (NPCl 2 Þ 3 with phenol is asequential reaction [166,169].The reaction type is different from the common one-stage reaction. The experimentalresults can easily demonstrate the relationship between the reaction kinetic limitationand the particle diffusion limitation. In atriphase reaction, the overall kinetic cycle canbe broken up into two steps by virtue of the presence of two practically insoluble liquidphases:achemicalconversionstepinwhichtheactivecatalystsites(Resin þ withphenolateions) react with the hexachlorocyclotriphosphazene in the organic solvent, and an ionexchangestep in which the attached catalyst sites are in contact with the aqueous phase:ð80ÞThe function of base in aliquid–solid–liquid triphasic reaction has four roles asmentioned above. In previous studies, it was observed that the reactivity of organic reactantvaried with the concentration of the base concentration in aliquid–liquid PT-catalyzedreaction [96,116,180]. In the liquid–solid–liquid triphase reaction, the effect of baseonthe reactivity of reactant (or reactive environment) was rarely paid attention to the k appand k app values dramatically increased with increasing concentration of NaOH when theratio of NaOH to C 6 H 5 OHwas in the range 1–1.5. This trend corresponds to that ofliquid–liquid phase-transfer catalysis [165]. The apparent activity energies for an organicreaction decreased, and for an aqueous reaction increased when the NaOH concentrationwas increased. The reactive behavior of the organic reaction changed from reaction chemicalcontrol to diffusion control E a