Catalytic hydroxylation of phenol over a vanadium silicate molecular sieve with MEL structure

Abstract

Vanadium silicate molecular sieves with MEL structure (VS-2) are found to be active in the hydroxylation of phenol with hydrogen peroxide, a reaction which is commercially practiced over titanium silicalite (TS-1 and TS-2) catalysts. Among various reaction parameters, the influence of the solvent on the conversion and product selectivity appears to be different from that reported on titanium silicalites. In methanol, for example, no hydroxylation takes place. In water, the phenol conversion as well as the H,Oa selectivity follows the order, T&l> TS-2 > VS-2. Only those vanadium ions which are in the lattice positions appear to catalyse this reaction