POROSITY AND THERMAL-STABILITY OF PILCS PREPARED WITH CLAYS FROM DIFFERENT ORIGINS AND DIFFERENT METAL-POLYHYDROXYCATIONIC SPECIES OF AL AND AL CE/

Montmorillonites from different origins have been pillared with polyhy droxycations of Al and Al/Ce in order to preferentially obtain pillare d clays with large pores and good thermal stability. The precursors of the stable materials, i.e. the intercalating species, and the interca lated but not calcined samples, were studied by differential scanning calorimetry. The textural properties of the materials obtained with di fferent pillaring solutions, and calcined at 500 and 700 degrees C, we re studied by nitrogen adsorption. It is shown that depending predomin antly on the oligomer composition and much less on the type of parent material, solids with different meso- and microporous volumes can be o btained with structures that, in some cases, present specific surface areas higher than 300 m(2) g(-1) at 700 degrees C.