OP-II-3

OP-II-8MATHEMATICAL MODELING OF β-PICOLINE OXIDATION TONICOTINIC ACID IN MULTITUBULAR REACTOR: EFFECT OF THERESIDUAL GAS RECYCLEOvchinnikova E.V. 1 , Vernikovskaya N.V. 1,2 , Andrushkevich T.V. 1 ,Chumachenko V.A. 11 Boreskov Institute of Catalysis SB RAS, address: pr. Akademika Lavrentieva, 5,Novosibirsk, 630090, Russia; e-mail: evo@catalysis.ru, ph.: +7 383 32694122 Novosibirsk State University, Pirogova St., 2, Novosibirsk, 630090, RussiaNicotinic acid (NA) forms directly fromβ-picoline (βР), as well as through intermediate70formation of pyridine-3-carbaldehyde [1]. When65conversion of βР (X) grows, selectivity to NA (S NA )60X,%drastically decreases due to the parallel route of0 20 40 60 80 100oxidation of NA to COx (Fig.1).Fig.1. S NA vs. Х in multitubular reactorOur former kinetic studies of βР oxidation overV 2 O 5 –TiO 2 catalyst [2] revealed the key influence of components О 2 /βР ratio on theactivity, selectivity and stability of the catalyst [1, 3]. This fact can be satisfactorilydescribed in terms of kinetic model [1]. On the grounds of dependence of NAaccumulation rate and of selectivity S NA and S COx on the ratio of the initial concentrationsО 2 /βР, we have shown that the reaction of βP90selective oxidation should be performed at801О 2 /βР=11÷20 (Fig.2). Within this interval, the rate of6NA production increases, while above 20 the yield of24complete oxidation products СOх increases, and28 10 12 14 16 18 20 22 24 26 28 30below 11 the catalyst reduction followed by itsInitial concentration O 2 /βPinactivation takes place [1, 3].Fig. 2. S NA (1) and S CO2 (2) vs.O 2 /βP atX≈60%. Lines – prediction, points –The use of recycling is widely known. Byexperiment.means of recycling the unreacted raw materialscould be returned into the process. For consecutive schemes, where the targetproduct is liable to further oxidation, the recycle after separation of such a productallows to increase its yield, due to prevention of the oxidation [4]. The possibility ofrecycle in the process of NA synthesis was briefly mentioned in [5]. The yield of NAmay be increased by 5-6% due to recycling, as mentioned in [6], where it wassupposed that the yield of NA increases only due to the drop in the “fresh” βР feed toSelectivity NA,%Selectivity, %8075112