Sulfated silica–titania aerogel as a bifunctional oxidative and acidic catalyst in the synthesis of diols

Sulfated silica–titania aerogel (SO4/ST) catalyst was prepared by direct synthesis and modified with H2SO4 by wet impregnation method. Brønsted acid sites were generated after sulfation of the silica–titania aerogel with a pKa of −14.52. Consecutive transformation of 1-octene, catalyzed by sulfated silica–titania aerogel using aqueous hydrogen peroxide as oxidant shows high activity towards 1,2-octanediol through the formation of 1,2-epoxyoctane. The formation of 1,2-octanediol is enabled by the co-existence of sulfated Ti species with Brønsted acid sites in the SO4/ST system. Sulfated silica-titania aerogel catalyst produced 1,2-octanediol (326 μmol) with selectivity of 63%. In contrast, no diol was produced when silica–titania aerogel was used.