Preparation of millimeter-sized spherical SiO2–Al2O3 with various acid catalysts for the acetalization of glycerol with acetone

Through the sol-gel-oil ammonia column method, millimeter-sized spherical SiO2–Al2O3 particles were successfully prepared using aluminum isopropoxide and varying amounts of tetraethyl orthosilicate. The impact of different Al/Si molar ratios on the structure and performance of SiO2–Al2O3 materials was thoroughly investigated. The surface of the samples was analyzed for acidic sites (Brønsted and Lewis acids) both qualitatively and quantitatively. The millimeter-sized spherical SiO2–Al2O3 materials were used as a catalyst in the Solketal production process, involving acetalization of acetone and glycerol. The glycerin conversion rate reached 88.67