NOVEL CATALYST SYSTEMS FOR PHENOL SYNTHESIS BY VAPOR-PHASE OXIDATION OF BENZOIC-ACID

Nickel, iron, and cobalt oxides showed excellent catalytic activities for the vapor-phase oxidation of benzoic acid to phenol at the reactio n temperature of 400 degrees C. The combination of these metal oxides, catalyst preparation by precipitation followed by calcination at 800 degrees C, and addition of Na2O to the catalyst about 1% by weight enh anced the conversion of benzoic acid and the selectivity to phenol. Th e structure of precipitation catalyst, Fe/Ni atomic ratio on the catal yst surface and formation of sodium benzoate on the catalyst surface p lay important roles for the optimization of catalyst activity. The nov el catalyst systems could throw a new light on a one-step phenol synth esis from toluene. Appreciable one-pass phenol yield was obtained usin g a binary catalyst system consisting of V2O5-K2SO4-TiO2 and NiO-Fe2O3 -Na2O, in which V2O5-K2SO4/TiO2 worked as a catalyst for toluene oxida tion to benzoic acid and NiO-Fe2O3-Na2O functioned as a catalyst for b enzoic acid to phenol.