High yield precipitation of crystalline α-zirconium phosphate from oxalic acid solutions.
Microcrystalline zirconium phosphate (ZrP) has been synthesized by precipitating a Zr(IV) salt (i.e., zirconium propionate, chloride, or oxide chloride) with H(3)PO(4) from aqueous solutions of oxalic acid (H(2)C(2)O(4)) at 80 °C. Independent of the Zr(IV) salt, crystalline materials have been obtained with reaction yields >90% and reaction time of one day for the following molar ratios: H(3)PO(4)/Zr = 6 and H(2)C(2)O(4)/Zr = 10. The material prepared from Zr propionate (ZrP(prop)) has been further investigated by scanning electron microscopy, thermogravimetry, and ion exchange titrations. Structural characterization has been performed by X-ray powder diffraction and solid state (1)H-(31)P 2D correlation NMR experiments. Structural parameters obtained by Rietveld analysis of powder diffraction data agree with those reported in the literature for single crystal determinations. Moreover, NMR data show that the closest proton environment of the phosphorus atom in ZrP(prop) is the same as in ZrP samples of similar crystallinity prepared according to literature methods.
Capitani
Donatella
D
Istituto di Metodologie Chimiche, Laboratorio di Risonanza Magnetica Annalaura Segre, CNR, Via Salaria km 29.300, 00016 Monterotondo Scalo (RM), Italy.
Casciola
Mario
M
Donnadio
Anna
A
Vivani
Riccardo
R