Mechanism for the Heterogeneous Exchange of the Interlayer Phosphate Groups of γ-Zirconium Phosphate with Phenyl Phosphate Groups

Article abstract of DOI:10.1021/j150654a026

Half of the interlayer phosphate groups of γ-zirconium phosphate crystals, Zr(HPO4)2*2H2O, are exchangeable with phenyl phosphate groups when the crystals are dispersed and heated in phenyl phosphoric acid solutions.The exchange occurs topochemically.The structure within the phosphate layer is maintained before and after the exchange, while the basal spacing of the crystals increases from 12.3 to 16.4 Angstroem.The rate-determining step of the exchange is a diffusion process with a diffusion coefficient of the order of 1E-13 - 1E-12 cm²/s at 70 deg C.The X-ray diffraction patterns of the exchanged products containing different proportions of phenyl phosphate groups indicate that the phenyl phosphate groups and the hydrogen phosphate groups are uniformly mixed in the interlayer region.