Three main routes of synthesis; namely the reflux, the direct precipitation, and the sol-gel methods, are used to prepare α-zirconium phosphate α-Zr(HPO 4 ) 2 .2H 2 O or simply α-ZrP. Within each separate method of synthesis, different starting precursors and/or reaction conditions are tested for optimization to obtain the crystalline product. Different products were characterized using TGA-DTA data, SEM photos, N 2 -gas absorption-desorption measurements, and FT-IR absorption spectra. The products showed different extents of crystallinitiy as roughly or qualitatively shown by their XRD patterns. The results are explained on the basis of each synthesis route and reaction conditions. In contrast to the familiar results that the initial un-refluxed product of rapid precipitation is basically amorphous ZrP, a careful washing strategy confirmed that this is a crystalline ZrP contaminated with a minority of solid H with a 1:1 mixture of mono-and diethyl phosphates were amorphous. Chemical analysis shows a reasonable agreement between the experimental ratios of P/Zr and the calculated values. Compared to other methods of synthesis, the direct precipitation seems to be more efficient in obtaining a product of good yield and improved crystallinity.

In a previous work 1 , we prepared α-Zr(HPO 4 ) 2 .2H 2 O (ZrP) by direct precipitation, reflux, and by sol-gel method. The results of characterization indicated that the properties of the resultant ZrP samples depended on the method and conditions of preparation as well as on the nature of precursor used. As an important factor governing the use of such layered phosphates, various modifications were done to enlarge the interlayer spacing of α-ZrP (7.6 Å) to be suitable for exchange of large cations. This work aims to modify the interlayer spacing of α-ZrP prepared from zirconium acetylacetonate complex and phosphoric acid. Two routes were used to achieve this goal; the first is by intercalation of acid α-ZrP with n-butyl amine in its vapor-saturated atmosphere. The second route is by performing ion-exchange of the α-ZrP protons by different cations.

In a previous work [1], we prepared -Zr(HPO 4 ) 2 .2H 2 O (ZrP) by direct precipitation, reflux, and by sol-gel method. The results of characterization indicated that the properties of the resultant ZrP samples depended on the method and conditions of preparation as well as on the nature of precursor used. As an important factor governing the use of such layered phosphates, various modifications were done to enlarge the interlayer spacing of -ZrP (7.6 Å) to be suitable for exchange of large cations. This work aims to modify the interlayer spacing of -ZrP prepared from zirconium acetylacetonate complex and phosphoric acid. Two routes were used to achieve this goal; the first is by intercalation of acid -ZrP with n-butyl amine in its vapor-saturated atmosphere. The second route is by performing ion-exchange of the -ZrP protons by different cations.