Cation–anion double hydrolysis derived mesoporous γ-Al2O3 as an environmentally friendly and efficient aldol reaction catalyst

Abstract

Parameters, such as crystallization temperature, pH, P123 content and aluminium source in the synthesis of mesoporous aluminas using the cation–anion double hydrolysis method (P. Bai, P. Wu, G. Zhao, Z. Yan and X. S. Zhao, J. Mater. Chem., 2008, 18, 74) were examined. With the assistance of characterization techniques, such as N₂ adsorption, X-ray diffraction (XRD), transmission electronic microscopy (TEM), selected area electron diffraction (SAED) and ²⁷Al magic-angle spinning (MAS) nuclear magnetic resonance (NMR), it was found that the parameters studied all have an influence on both the textural properties and the crystalline structure of the resultant solid materials. Dependence of the catalytic activity of the mesoporous alumina materials on the synthesis parameters was observed. The observed remarkably high catalytic activity of the mesoporous alumina materials is attributed to the high surface area, surface basicity, pure γ-Al₂O₃ phase and absence of anion residues, such as SO₄²⁻.