Sol-gel synthesis of mesostructured aluminas from chemically modified aluminum sec-butoxide using non-ionic surfactant templating

This paper reports on the effect that chemical modification of the aluminum sec-butoxide precursor with several chelating ligands has on the structure and textural properties of nanoporous aluminas obtained via a non-ionic surfactant templating approach. Characterization of the samples is carried out by elemental analysis, thermogravimetric analysis coupled to mass spectrometry, Fourier transform infrared spectroscopy, nitrogen adsorption-desorption, X-ray powder diffraction, transmission electron microscopy and Al-27 magic angle spinning nuclear magnetic resonance. The catalytic activity in the hydroisomerization of hexane is evaluated for platinum-containing fluorided samples. Chemical modification of the aluminum sec-butoxide promotes the formation of penta- and tetracoordinated aluminum and modifies the alumina porous structure. Higher intrinsic activity is exhibited by catalysts based on these aluminas as compared to those prepared from the unmodified alkoxide, indicating an enhanced acidity of the support. (c) 2005 Elsevier Inc. All rights reserved.