Microporous zirconia from anionic and neutral surfactants

The hydrolysis of zirconium isopropoxide in the presence of a bitailed sulf ate (Niaproof 4) or of a neutral surfactant (Tergitol 7) yields microporous solids with specific Langmuir surface areas between 100 and 250 m(2) g, de pending upon the concentration in surfactant and the pH of preparation. On the sole basis of the pore volume, surface area and thermal stability the m icroporous zirconias described here cannot compete with the mesoporous zirc onias obtained from anionic surfactants, The emphasis of this contribution is the study of another aspect of the scaffolding mechanism proposed earlie r. It seems that it can be extended to the formation of lamellar phases. Wh en hydrolysis is mediated through carboxylic acids (from C-10 to C-18), the lamellar solids do not have porosity when loaded by the acids, and the pos ition of the basal reflection depends upon the chain length, This observati on is in general agreement with the earlier conclusion of Ying et al. In th e other lamellar structures the basal X-ray reflection probably depends upo n the inter-stratification of layers with different thicknesses. (C) 1999 E lsevier Science B.V. All rights reserved.