Modifying the reactivity of a solid Lewis acid: niobium and antimony doped nanoscopic aluminum fluoride

A series of acid catalysts were prepared, using niobium and antimony as dopants in the fluorolytic sol-gel synthesis of high surface aluminium fluoride. These new catalysts exhibit remarkable reactivity: they are able to isomerize compounds containing carbon-halogen bonds at room temperature by C-F, C-Cl and C-Br activation and perform the isomerization of double bonds and Friedel-Crafts-like reactions that are required for the cyclization of citronellal, for which the conversions increase by doping with Nb up to 99%. Furthermore, the characterization of the catalysts by means of MAS NMR, NH3-TPD, py-PAS and N-2 adsorption is presented.