Effect of vanadia on the performance of NiO in vapor-phase oxidative decarboxylation of benzoic acid to phenol

A series of vanadia-loaded NiO catalysts was tested for the vapor-phase oxidative decarboxylation of benzoic acid to phenol at 673 K. NiO catalyzed the selective formation of phenol at low conversions of benzoic acid. However, the phenol yield declined with time on stream. Introduction of vanadium oxide to the catalyst resulted in pronounced improvements in the phenol yield and its stability, whereas V ₂O ₅ alone predominantly catalyzed the combustion of benzoic acid to carbon oxides. Under identical testing conditions, the highest selectivity to phenol (46.9%) was obtained with a 0.49 wt% V ₂O ₅ sample, while the highest phenol yield of 7.6% was obtained on a 3.7 wt% V ₂O ₅ sample.