Influence of the synthesis conditions on the preparation of titanium-pillared clays using hydrolyzed titanium ethoxide as the pillaring agent

Titanium-pillared clays (Ti-PILCs) have been prepared using a commercial bentonite and a reaction mixture containing titanium ethoxide. The structure and properties of the pillared materials were studied by X-ray diffraction, N2 adsorption, chemical analysis, thermal analysis, and temperature-programmed desorption of ammonia. Materials with a high content of micropore area (≈90%) and a basal spacing of about 24 Å were obtained. When the synthesis was carried out using a molar ratio HCl/Ti=2.5, a homogeneous pillared sample with a high micropore area was obtained. The structural and textural Ti-PILC properties were enhanced when the process was performed at room temperature and with the slowest addition speed of the pillaring solution to the clay suspension. There is a limit in terms of the number of titanium polynuclear species that can be incorporated as pillars within the clay, and this was found to be 15 mmol Ti/g clay. The use of an aqueous suspension of 0.15 wt.% of clay yielded the best structural and textural properties. The synthesized titanium pillared clays were found to be thermally stable up to 500 °C.Financial support from The European Commission (Contract ERK5-CT-1999-00001) is gratefully acknowledged.Peer reviewe