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 reaction 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 enhanced the conversion of benzoic acid and the selectivity to phenol. The structure of precipitation catalyst, Fe/Ni atomic ratio on the catalyst surface and formation of sodium benzoate on the catalyst surface play important roles for the optimization of catalyst activity. The novel catalyst systems could throw a new light on a one-step phenol synthesis from toluene. Appreciable one-pass phenol yield was obtained using a binary catalyst system consisting of V2O5-K2SO4-TiO2 and NiO-Fe2O3-Na2O, in which V2O5-K2SO4/TiO2 worked as a catalyst for toluene oxidation to benzoic acid and NiO-Fe2O3-Na2O functioned as a catalyst for benzoic acid to phenol.