A new series of hydrotalcite (HT)-like anionic clays containing Zr 4+ in the brucite-like layer has been synthesized by a simple coprecipitation method at constant pH. The incorporation of Zr in the layer has been investigated by various analytical methods, such as powder X-ray diffraction (PXRD), chemical analysis, FT-IR, ultraviolet-visible diffuse reflectance (UV-vis DR) spectra, and thermogravimetric analysis (TGA). The PXRD of assynthesized samples showed that the crystallinity of the material decreased with increasing Zr content due to the distortions introduced by the incorporation of the larger cation, Zr. Thermal calcination at 723 K results in the formation of a poorly crystalline MgO phase in which some of the Zr 4+ cations are dissolved. The crystallinity of the resulting MgO phase decreases with increasing Zr content and forms a ZrO 2 phase, in addition to the MgO phase, at higher Zr content. Calcination at higher temperatures (>1000 K) yields a mixture of MgO, MgAl 2 O 4 spinel, and ZrO 2 phases. The UV-vis DR spectra showed that the Zr 4+ cations are well-dispersed in both uncalcined as well as in calcined samples, similar to that in Zrsilicalites.

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Titanium silicalite-1 (TS-1) was synthesized using ethyl silicate-40 as a new silica source for zeolite synthesis. This procedure is advantageous because of the higher rate of crystallization, enhanced incorporation of Ti and the highly pure sub-micron sized crystalline product, which is highly active for phenol and anisole oxidation by aqueous H 2 O 2 , furthermore, ES-40 is cheaper compared to tetraethyl orthosilicate (TEOS). The product was characterized by XRD, IR, SEM, UV±VIS and XRF spectroscopy and adsorption studies. The nature of the silicate species in the intermediate stages of the synthesis was characterized by studying the 29 Si liquid NMR spectra. It was observed that if tetrabutyl orthotitanate (TBOT) was mixed with ES-40 before hydrolysis while preparing the reactive solution precursor, the Q 3 type of silicate species were predominantly formed, which resulted in faster crystallization of TS-1.