Synthesis, characterization, and catalytic properties of pillared montmorillonite with aluminum/cerium polyoxycations

This paper describes the preparation of pillared montmorillonite by means o f mixed aluminum and cerium oligomers. When cerium was incorporated into th e materials, the basal spacing increased up to 26 Angstrom. Nuclear magneti c resonance studies indicated total absence of tetrahedral aluminum in the polyoxycations incorporated between the clay sheets. These results indicate that AlCe-pillared montmorillonite incorporates inorganic polyoxycations w ith a chemical nature different from that of the aluminum polyoxycation or Keggin ion [AlO4Al12(OH)(24)(H2O)(12)](7+) The texture of the materials sho wed a high specific surface area and porosity, with generation of pores at the limit between the microporous and mesoporous zones. The number and stre ngth of the acid sites in these materials were also high. The catalytic beh avior of the materials in the hydrocracking and hydroisomerization reaction of n-heptane was compared with that of materials obtained from the same mo ntmorillonite and intercalation of the Keggin ion. The AlCe-pillared sample s showed increased conversion and improved the selectivity toward the produ cts of cracking.