Effectof Reaction Medium on V-Ti Oxide Catalyst Composition in
V.M. Pochtennaya and D. Kh.Sembaev
Institute of Chemical Sciences of Ministry of Education and Science of the Republic of Kazakhstan,
106 Ualikhanov Str., 480100, Almaty, Kazakhstan
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 V2O5 content gradient in the catalyst. V2O5 concentration increases in the conditions of alkylpyridine completed conversion in consequence of oxidative decomposition of VO2-TiO2 solid solution under the influence of N2O nitrogen oxide, which is formed upon the NH3 oxidation. An increase of V2O5 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 V2O5 is corresponding to, for any given conditions of oxidative reaction. The catalysts containing 1-5 wt% of V2O5 and solid solution of VO2-TiO2 possess of the highest selectivity to nicotinonitrile.