An organic sensitizer within Ti-zeolites as photocatalyst for the selective oxidation of olefins using oxygen and water as reagents

A new positive photocatalytic system comprising an organic dye within the m icropores of a titanium zeolite is able to effect the catalytic dihydroxyla tion of alkenes using water and molecular oxygen as reagents; the dye acts as an antenna to absorb the energy of visible light, generating hydroxyl ra dicals from water; subsequently, the OH. radicals react with olefins in the presence of oxygen to form allylic hydroperoxides that in the presence of the Ti atoms of the zeolite promote the epoxidation of the alkene.