PILLARING OF A HIGH IRON CONTENT SAPONITE WITH ALUMINUM POLYCATIONS -SURFACE AND CATALYTIC PROPERTIES

A high iron content saponite from Griffith Park, CA, (griffithite vari ety) was pillared by aluminum polycation solutions with different Al/c lay ratios. X-ray diffraction shows that the intercalation process beg ins when aluminum polycation solutions are added, being completed duri ng 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 are a of the intercalated solids is about 300 m(2) g(-1), decreasing about 20% for pillared samples (calcinated at 500 degrees C). The total aci dity ranges between 470 and 615 mu mol g(-1), and the pyridine adsorpt ion indicates the existence of only Lewis acid sites. The materials ar e very active in the dehydration of 2-propanol giving rise exclusively to propene, with activities of around 30 mu mol g(-1) s(-1).