Synthesis, characterization and catalytic behavior of V-Si-β molecular sieves

V-beta molecular sieves through isomorphous replacement of Si by V in zeolite beta were successfully synthesized via hydrothermal procedure. The synthesis conditions were as follows: the molar chemical composition of the mixture: 60SiO(2)-xV(2)O(5)-y(TEA)(2)O-zH(2)O-wNH(4)F (1 <= x <= 6, y >= 16, 500 <= z <= 800, w >= 5); reaction temperature 413 K, reaction time 12 d. The synthesized samples are characterized by XRD, IR, UV-Vis, TG, DTA and SEM. The results confirm that V-beta molecular sieves contain a beta phase of good species, and show the presence of V iron in the framework position. In the system the catalytic behavior of V-beta molecular sieves in the hydroxylation of phenol with H2O2 as the oxidant was also investigated.