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Direct oxidation of benzene to phenol with dioxygen is an attractive and challenging subject. V4+ vanadium species play an important role in the reaction. Nano vanadium oxide which consists mainly of the quadrivalence vanadium species was synthesized via hydrothermal method and used to catalyze the reaction without addition of reducing reagent. Investigations about performances of catalysts show that 3.7% conversion of benzene and nearly 100% selectivity of phenol are given over the fresh catalyst VO-N-A. Morphology observations display that the VO-N-A is made of nano-plate. Thermogravimetric curve illuminates that the catalyst is stable under the reaction temperature. [ABSTRACT FROM AUTHOR]

Abstract: The highly selective direct hydroxylation of benzene with hydrogen peroxide to phenol was observed on a clay-supported vanadium oxide catalyst. Under mild reaction conditions at 313 K, high selectivity to phenol of 94% was realized on the clay-supported vanadium oxide catalyst at 14% conversion of benzene, comparable with the well-known TS-1 catalyst. On the other hand, vanadium on other supports and other metals on the clay support gave inferior catalytic performances. V–O–Al and V–O–Si bridges in the catalyst may be responsible for the reaction. [Copyright &y& Elsevier]