Homogeneous Boroaluminate Xerogels: Synthesis, Characterization, and Catalysis

We developed the preparation method for mesoporous boroaluminates with a high surface area by the non-hydrolytic sol-gel (NHSG) reactions of Al(OiPr)3 and BCl3 in dry toluene with a 1:1 boron/aluminum precursor ratio. Mixed boria-alumina xerogels were prepared by alkyl-halide condensation reaction with the elimination of isopropyl chloride. This reaction led to amorphous xerogels with a homogeneous distribution of boron and aluminum atoms in the network structure. The surface area of the resulting mixed oxides reaches up to 600 m2 g-1 without a templating agent. Additionally, we compared the results with materials prepared by different non-hydrolytic sol-gel methods. We characterized our materials by 11B and 27Al MAS NMR spectroscopy, SEM and STEM-EDS microscopy, N2 porosimetry, and thermogravimetry, combined with ICP-OES and XPS elemental analysis. We also investigated its practical application in catalysis, in ethanol dehydration reaction to ethylene and diethyl ether.