A new challenge for nanocrystalline α-zirconium phosphate: reaction with a diepoxyalkane

Abstract

New organic derivatives of α-zirconium phosphate (ZrP) were prepared by reaction of a gel of nanocrystalline ZrP with 1,2,7,8-diepoxyoctane (diepoxide), leading to the formation of P–O–C bonds. A series of compounds having composition Zr(O₃POH)_2−2x(O₃POCH₂CH(OH)(CH₂)₄CH(OH)CH₂OPO₃)_x (hereafter indicated as ZrP(dep)_x) were obtained by varying the diepoxide/Zr molar ratio in the range 0.25–1. The samples were characterized by elemental, thermal and X-ray powder diffraction analysis. The reaction turned out to be nearly quantitative, the x values of ZrP(dep)_x being in the range 0.16 to 1.0. The interlayer distance slightly increased with increasing x, going from 12.7 to 13.2 Å. Interestingly, the materials easily intercalated alkanols at room temperature, both from liquid and vapor phases; it is noteworthy that ZrP(dep)_0.30 was able to reversibly take up 42 wt% ethanol from the vapor phase, in agreement with the presence of available free space both in the interlayer and in the intercrystal region. Geometrical structural models in which the α-ZrP layers are connected by the dep chains were proposed to support the obtained results.