MODELING AND EXPERIMENTAL-STUDY OF A SEQUENTIAL PHOSPHAZENE REACTION BY PHASE-TRANSFER CATALYSIS

The substitution reaction of hexachlorocyclotriphosphazene, N3P3Cl6, w ith phenol was performed to synthesize the partially substituted (phen oxy) chlorocyclotriphosphazenes, N3P3Cl6-i(OC6H5)(i), i = 1-6 by phase -transfer catalysis (PTC) in an organic phase/alkaline solution. The s teric hindrance effect plays a crucial role in this reaction. The reac tion system was controlled by both chemical kinetics and mass-transfer effects. The mass transfer of the catalyst between two phases was inv estigated by a pseudo-steady-state liquid-liquid PTC (LLPTC) model. Al so, the intrinsic reaction-rate constants of the series substitution a nd the overall mass-transfer coefficient of the catalyst from the orga nic phase to the aqueous phase were determined by a combined model. In addition, the corresponding energies, enthalpies, and entropies of ac tivation of the series substitution were also estimated.