Microporous zirconia from anionic and neutral surfactants

The hydrolysis of zirconium isopropoxide in the presence of a bitailed sulfate (Niaproof 4) or of a neutral surfactant (Tergitol 7) yields microporous solids with specific Langmuir surface areas between 100 and 250m²g, depending upon the concentration in surfactant and the pH of preparation. On the sole basis of the pore volume, surface area and thermal stability the microporous zirconias described here cannot compete with the mesoporous zirconias obtained from anionic surfactants. The emphasis of this contribution is the study of another aspect of the scaffolding mechanism proposed earlier. It seems that it can be extended to the formation of lamellar phases. When hydrolysis is mediated through carboxylic acids (from C₁₀ to C₁₈), the lamellar solids do not have porosity when loaded by the acids, and the position of the basal reflection depends upon the chain length. This observation is in general agreement with the earlier conclusion of Ying et al. In the other lamellar structures the basal X-ray reflection probably depends upon the inter-stratification of layers with different thicknesses.