LOW-TEMPERATURE, EFFICIENT SYNTHESIS OF NEW AS(V)-SILICATE MOLECULAR-SIEVES WITH MFI TOPOLOGY AND THEIR CATALYTIC PROPERTIES IN OXIDATION REACTIONS

New MFI type arseno-silicate molecular sieves (As(V)-MFI), synthesized for the first time, can be crystallized at lower temperature (70-90 d egrees C) in 1-3 days under hydrothermal conditions. Interestingly, th ese As(V)-MFI molecular sieves can be synthesized even faster than the As-free silicalite-l under identical conditions. Further, the crystal lization becomes faster with the increase in As content of the reactio n mixture, contrary to the observations made on all the other high sil ica molecular sieves, so far. These microporous As(V)-silicates exhibi t significant catalytic activity in (i) phenol hydroxylation using 30% aq. H2O2 (ca. 55% H2O2 efficiency) and (ii) oxidative dehydrogenation of 2-butanol and benzyl alcohol using air under fixed bed vapor phase reaction conditions exhibiting ca. 75-85% selectivity towards 2-butan one and benzaldehyde + benzoic acid, respectively.