Na-montmorillonite and its Al-, Ti-, Fe-, Cr-, Zr- and Sn-pillared derivatives (pillared layer clays) were prepared and characterized by instrumental methods and a chemical reaction. Structural characterization involved X-ray fluorescence (XRF) analysis, X-ray diffractometry (XRD), 29Si and 27Al MAS NMR spectroscopies, thermogravimetric (TG) and BET measurements. By the distinctly characteristic shapes of the d001 vs. temperature curves two groups could be distinguished, (i) Al-PILC, Ti-PILC, Cr-PILC, Zr-PILC and (ii) Fe-PILC, Sn-PILC, Na-montmorillonite. On montmorillonite isomerization of cyclopropane only occurred while oligomerization followed isomerization over Al-PILC. This latter reaction was attributed to Lewis and (the considerably smaller number of) Brönsted acid sites whose number, strength and accessibility increased due to pillaring.
- Pillared layer clays
- Surface acidity
- Thermal characteristics
ASJC Scopus subject areas
- Physical and Theoretical Chemistry