Highly regioselective oxybromination in an aqueous system using SBA-15 supported sulfated zirconia catalyst

SBA-15 supported sulfated zirconia (SZ) catalysts were employed in many acid-catalysis of reactions under mild condition because it is a strong solid acid with various Lewis and Br0nsted acid sites. An oxybromination of aromatic substrates using hydrogen peroxide and ammonium bromide in the aqueous phase under mild temperature and near-neutral pH condition over SZ was achieved. A good to excellent para-selectivity was observed. The mesoporous silica SBA-15 supported SZ possessed higher catalytic activity than self-supported SZ because of larger surface area and pore size. The effect of the calcinations temperature was also investigated. The good catalytic performance of the SZ/SBA-15 materials was attributed to high degree of dispersion of sulfate groups to give sulfated silica-zirconia of (1) very good redox property and (2) high strength and high density of acid sites. The SZ/SBA-15 catalyst may be re-used several times without substantial loss of activity.