Methanolysis of styrene oxide catalysed by a highly efficient zirconium-doped mesoporous silica

Highly ordered zirconium doped hexagonal mesoporous silicas with Si/Zr ratios of 40:1 and 80:1 have been used as solid acid catalysts for the methanolysis of styrene oxide in a single-mode microwave reactor. The catalysts demonstrated excellent substrate conversion, high product selectivities and were shown to remain highly active for several reaction cycles. The catalyst was regenerated by microwave irradiation in methanol. The effects of concentration of zirconium dopant and reaction time were studied. Products of the reaction were identified by a combination of GC-MS and 1H NMR as 2-methoxy-2-phenylethanol (1), phenyl-acetaldehyde (2), phenylacetaldehyde dimethyl acetal (3) and 1-(1-methoxy-2-(phenethyloxy)ethyl)benzene (4). The relative amounts of these products depended on the zirconium concentration and the reaction time. Thus, with 40:1 Si:Zr catalyst, compounds (1) (93%), (2) (5%) and (3) (2%) were produced after 5 min reaction but only (1) (93%) and (3) (7%) were observed after 10 min.