Abstract:

V-β molecular sieves through isomorphous replacement of Si by V in zeolite β were successfully synthesized via hydrothermal procedure. The synthesis conditions were as follows: the molar chemical composition of the mixture: 60SiO₂-xV₂O₅-y(TEA)₂O-zH₂O-wNH₄F ( 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-β molecular sieves contain a β phase of good species,and show the presence of V iron in the framework position. In the system the catalytic behavior of V-β molecular sieves in the hydroxylation of phenol with H₂O₂ as the oxidant was also investigated.

Key words: V-β molecular sieve; Catalytic behavior; Phenol; Hydroxylation