Effect of Reaction Medium on V-Ti Oxide Catalyst Composition in 2-Methyl-5-Ethylpyridine Ammoxidation

Abstract

<p>A chemical composition of V-Ti oxide catalyst changes in accordance with the reaction medium composition in a process of 2-methyl-5-ethylpyrydine ammoxidation into nicotinonitrile in an integral reactor. The presence of alkylpyridine concentration gradient along the catalyst bed leads to the appearance of V<sub>2</sub>O<sub>5</sub> content gradient in the catalyst. V<sub>2</sub>O<sub>5</sub> concentration increases in the conditions of alkylpyridine completed conversion in consequence of oxidative decomposition of VO<sub>2</sub>-TiO<sub>2</sub> solid solution under the influence of N2O nitrogen oxide, which is formed upon the NH<sub>3</sub> oxidation. An increase of V<sub>2</sub>O<sub>5</sub> contents over 5 wt% causes rising of the share of the 2-methyl-5-ethylpyridine and nicotinonitrile destructive oxidation. An introduction of small amounts of alkylpyridine directly into the catalyst bed permits to create the definite alkylpyridine concentration gradient, which the optimal content of V<sub>2</sub>O<sub>5</sub> is corresponding to, for any given conditions of oxidative reaction. The catalysts containing 1-5 wt% of V<sub>2</sub>O<sub>5</sub> and solid solution of VO<sub>2</sub>-TiO<sub>2</sub> possess of the highest selectivity to nicotinonitrile.</p>