Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-I-11KINETICS STUDIES AND MECHANISM OF β-PICOLINE OXIDATIONTO NICOTINIC ACID OVER V 2 O 5 –TiO 2 CATALYSTE.V. Ovchinnikova, G.Ya. Popova, T.V. Andrushkevich, V.A. ChumachenkoBoreskov Institute of Catalysis SB RAS, pr. Akademika Lavrentieva, 5, Novosibirsk, 630090,Russia; e-mail: evo@catalysis.ru , phone: +7 383 3269412IntroductionThe gas-phase catalytic oxidation of β-picoline over oxide vanadia-titania catalysts allowsthe nicotinic acid (NA) production with the yield above 80% [1-3]. A previous study of thisreaction with β-picoline conversion 20-85% revealed a parallel-consecutive scheme of NAformation, via the intermediate pyridine-3-carbaldehyde (PA) and directly from β-picoline(βP) [4]. The prospect of industrial implementation of this method makes it necessary to studykinetics and to develop a kinetic model applicable to real-shaped pellets of the catalyst.Experimental procedureThe catalyst 20%V 2 O 5 –80%TiO 2 (wt.%) was prepared by spray drying of an aqueoussuspension of vanadyl oxalate and TiO 2 (anatase) followed by its shaping into rings 2 mm ID,4 mm OD and 5 mm length and calcining in air at 450 °C [1]. The BET specific area of thecatalyst was 25 m 2 /g.The kinetic studies were performed in a differential reactor in a flow-circulating setupwith chromatographic analysis of the reaction mixture components.Kinetic experiments were performed at ambient pressure and range temperature 250-300 °C over a wide range of reagent initial concentrations, %vol.: 0.5-2.5% of βP, 10-22% ofO 2 , 5-40% steam, and nitrogen – balance.In situ FTIR spectroscopy was used to study the mechanism of oxidation of βP and PAinto NA on a V 2 O 5 –TiO 2 catalyst.Results and discussionIn fig., the rate of βP consumption and the rates of product accumulation (a) andselectivities (b) are shown as a function of βP conversion in the temperature range 270-300 °C. The main product of the reaction in the whole investigated range of conversion is NA.Selectivity to it is 85-90 %, other products is 3-pyridine nitrile (PN) and carbon oxides (COx).The complementary support of a parallel-consecutive network for the NA formation is aFTIR in situ study of βP and PA oxidation. NA is formed through the same surface speciesfrom βP as well as from PA [5, 6].231