Formation of active state in vanadium–titanium oxide system regarding to reaction of oxidation of β-picoline to nicotinic acid

Binary vanadia–titania catalysts comprising 5–75 wt.% of V₂O₅ and 95–25 wt.% of TiO₂, pretreated at the temperature ranging between 300 and 700°C, were studied as heterogeneous catalysts for oxidation of β-picoline at 250°C, and inlet concentrations of the following components (vol.%): 1% of 3-picoline, 20% of oxygen, 30% of steam. Nicotinic acid, 3-pyridinecarbaldehyde and CO₂ were the reaction products. The most active state for oxidation of 3-picoline into nicotinic acid was shown to result from formation of coherent interface between V₂O₅ and TiO₂ (anatase) crystallites. This state was generated at the temperature particular for each composition and persists below the temperature of the anatase to rutile transition.