a versatile methodology to obtain efficient catalytic materials suitable for selective , liquid - phase oxidations of alcohols is described . solid inorganic membranes were prepared by the sol - gel procedure by adding a solution of stable organic nitroxyl radicals at the onset of the polymerization of silicon alkoxide monomers . in this way , micro - and mesoporous materials can be obtained that axe effective and recyclable catalytic mediators for highly selective oxidations of a vast class of primary and secondary alcohols carried out with several primary oxidants . delicate substrates such as carbohydrates and allylic alcohols can selectively be oxidized with these novel catalytic materials .