Room temperature ionic liquid-assisted synthesis of mesoporous γ-alumina

In this Letter, mesoporous γ-aluminas have been successfully synthesised by calcining self-synthesised alumina sol in the presence of room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate. N₂-adsorption measurements presented that the ionic liquid had a significant influence on the textural structure of the final product. Aluminas prepared in this way displayed very rich porosities with large mesopores. As the ionic liquid concentration (IL/Al molar ratio) increased successively from 0 to 0.10, the products showed much larger pore volumes (0.30-1.26-cm³/g) and higher specific surface areas (247-339-m²/g). X-ray diffraction patterns and ²⁷Al magic-angle spinning nuclear magnetic resonance spectra revealed that the self-synthesised alumina sol first transformed into boehmite phase and then became well-crystallised γ-alumina particles by calcining at 500°C.