OXIDATIVE ORGANIC TRANSFORMATIONS CATALYZED BY TITANIUM-SILICATE AND VANADIUM-SILICATE MOLECULAR-SIEVES

Titanium- and vandium-silicate molecular sieves like TS-1/VS-1 and TS- 2/VS-2 oxidize a variety of organic substrates e.g., alkanes, olefins, unsaturated alcohols, aldehydes, aromatics, amines and thioethers etc , under heterogeneous catalytic conditions using dilute hydrogen perox ide (30% aq.). Considerable regio-, stereo- and chemo-selectivity has been observed in above studies. Compared to V-silicates (VS-1/VS-2), T i-silicates (TS-1/TS-2) are efficient in H2O2 utilization. V-zeolites can oxyfunctionalize even primary C-H bond in n-alkanes and side chain in alkyl substituted aromatics. Large pore V-zeolite (V-NCL-1) oxidiz es even bulky aromatic compounds like xylenes, trimethyl benzenes, nap hthalene etc. Mechanistically, heterolytic cleavage of H2O2 is preferr ed by TS-1/TS-2, whereas VS-1/VS-2 may involve homolytic cleavage.