Liquid-phase oxidation of alcohols by manganese containing mesoporous molecular sieves (Mn-HMS) catalyst

Recently there has been an increasing interest in the development of heterogeneous catalysts for the oxidation of alcohols in the liquid phase with molecular oxygen, aqueous hydrogen peroxide, or terbutylhydroperoxide(TBHP). Heterogeneous catalytic oxidations of alcohols find wide chemical and biological applications besides synthetic applications in pharmaceutical industries. The selective oxidation products serve as the starting materials for the production of several fine chemicals and polymers. After achieving a tremendous success in the selective oxidation of organic substrates over titanium silicalites, researchers succeeded in incorporating various transition metal cations, particularly Ti and V, in the framework of a large number of zeolites and molecular sieves. However, all these microporous materials have a common drawback which is the limited accessibility of active sites to large substrate molecules. Mesoporous silicates lent themselves to modification by transition metal cations. Both MCM-41 and HMS silicates have been modified by Ti and V. HMS designates a family of crystalline mesoporous materials prepared mostly in the presence of amine surfactants. The objectives of the present investigation were to prepare and characterize Mn-HMS mesoporous materials and liquid phase oxidation of alcohols over Mn-HMS catalyst in the presence of TBHP as the oxidant and kinetic study of oxidation reaction.