Hydroxylation of 1-naphthol by hydrogen peroxide over UL-TS-1 and TS-1 coated MCF Original Research Article

Two different kinds of titano-silicate zeolite/mesoporous molecular sieves (MMS) materials have been produced following techniques proposed recently in our laboratory. The composite materials designated as UL-TS-1 are obtained by solid phase templated crystallization of a thick walled titanosilicate mesoporous molecular sieves yielding TS-1 nanoparticles in the MMS pore walls. The TS-1 coated mesoporous cellular foams (MCF) are obtained by contacting a clear gel containing protozeolite units of TS-1 with a large pore Ti-MCF. After complete characterization of their textural and surface chemical properties, these solids were used as catalysts in the oxidation of a bulky molecule 1-naphthol by aqueous hydrogen peroxide. Their activities are compared to those of TS-1 and Ti-MMSs as reference materials. UL-TS-1 showed a high specific activity due to their high nanoparticle external surface area whereas successive coatings induced specific activity enhancement of the TS-1 coated Ti-MCF. In both cases, additional activity enhancement was induced by trimethylsilylation of residual OH’s by hexamethyldisilazane (HMDS).