Pillaring of a High Iron Content Saponite with Aluminum Polycations: Surface and Catalytic Properties

A high iron content saponite from Griffith Park, CA, (griffithite variety) was pillared by aluminum polycation solutions with different Al/clay ratios. X-ray diffraction shows that the intercalation process begins when aluminum polycation solutions are added, being completed during the dialysis washing of the samples. The amount of Al fixed by the intercalated solids is about 1.6 mmol of Al/g of clay. The surface area of the intercalated solids is about 300 m 2 g - 1, decreasing about 20% for pillared samples (calcinated at 500 °C). The total acidity ranges between 470 and 615 μmol g - 1, and the pyridine adsorption indicates the existence of only Lewis acid sites. The materials are very active in the dehydration of 2-propanol giving rise exclusively to propene, with activities of around 30 μmol g - 1 s - 1 .