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Abstract--By ion exchanging expandable clay minerals with large, cationic oxyaluminum polymers, "pillars" were introduced that permanently prop open the clay layers. On the basis of thermal, infrared spectroscopic, adsorption, and X-ray powder diffraction (XRD) analysis, the interlayering of commercial sodium bentonite with aluminum chlorohydroxide, lAI1304(OH)24(HzO)12] +7, polymers appears to have produced an expanded clay with a surface area of 200-300 m2/g. The pillared product contained both Br6nsted and Lewis acid sites. XRD and differential scanning calorimetry measurements indicated that the micropore structure of this interlayered clay is stable to 540~ Between 540 ~ and 760~ the pillared day collapsed with a corresponding decrease in surface area (to 55 m2/g) and catalytic cracking activity for a Kuwait gas oil having a 260~176 boiling range.

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A hybrid density functional theory (DFT) method has been used to interpret the data for the adsorption of nitrogen at 77 K within the porous structure of a sample of synthetic saponite expanded with stable SiO2·TiO2 colloidal particles and dried by different methods. Air drying (AD) favor the formation of structures containing both micro- and mesopores. In contrast, drying with supercritical CO2 (SCD) produces mesoporous solids containing only minor amounts of micropores. In SCD samples, the total PV is more than 5 times higher than in AD samples and their structure is hydrothermally stable after a 5-h exposure to 100% steam at 760 °C. Adsorption microcalorimetry experiments with ammonia indicate that the inclusion of SiO2·TiO2 clusters drastically increases the clay total (B + L) acidity; acid site strength and acid site density is greatest in AD samples. Both the BET and BJH methods underestimate the clay catalyst's surface area and only the DFT method yields reliable surface area and pore volume measurements over the entire micro−meso porosity range investigated.