Precursor structure and microstructure of Al2O3 xerogels prepared from aluminum-tri-sec-butoxide chemically modified with mono-, di-, tri-ethanolamines

The precursor structures of aluminum-tri-sec-butoxide (Al(O-sec-Bu)(3)) chemically modified with alkanolamines, such as mono-, di-, and tri-ethanolamines, were investigated using Al-27 NMR. Those spectra revealed that the addition of these alkanolamines led to the structural change around Al atoms and peak half-width decreased with an increase in the number of OH groups in the alkanolamine molecules. The specific surface area of the gels prepared using triethanolamine, which has the strongest stabilizing ability among these alkanolamines, was smaller than the gels using monoethanolamine or diethanolamine. The specific surface area and pore size distribution of Al2O3 gels were thus controllable with varying the kind of alkanolamines.