CHARACTERIZATION OF CATIONIC PILLARED LAYER CLAYS

Na-montmorillonite and its Al-, Ti-, Fe-, Cr-, Zr- and Sn-pillared der ivatives (pillared layer clays) were prepared and characterized by ins trumental methods and a chemical reaction. Structural characterization involved X-ray fluorescence (XRF) analysis, X-ray diffractometry (XRD ), Si-29 and Al-27 MAS NMR spectroscopies, thermogravimetric (TG) and BET measurements. By the distinctly characteristic shapes of the door vs. temperature curves two groups could be distinguished, (i) Al-PILC, Ti-PILC, Cr-PILC, Zr-PILC and (ii) Fe-PILC, Sn-PILC, Na-montmorilloni te. On montmorillonite isomerization of cyclopropane only occurred whi le oligomerization followed isomerization over AI-PILC. This latter re action was attributed to Lewis and (the considerably smaller number of ) Bronsted acid sites whose number, strength and accessibility increas ed due to pillaring.