Catalysts for Alkylbenzene and Alkylpyridine Ammoxidation

Abstract

<p>An increase of effectivity of binary and ternary vanadium containing oxide catalysts can be achieved by a regulation of chemical and phase catalyst composition during their preparation. Activity and selectivity of V-Ti catalysts depend on the ratio of V<sub>2</sub>O<sub>5</sub> to VO<sub>2</sub> in the succession of substitutional solid solutions VO<sub>2</sub>- TiO<sub>2</sub>, as well as on the crystal modification of TiO<sub>2</sub>. It was investigated the influence of vanadium oxides over the rate of the polymorfous conversion from anatase to rutile and the kind of TiO<sub>2</sub> crystal modification over V<sub>2</sub>O<sub>5</sub> reduction degree during the thermal treatment of V-Ti catalysts. The synthesized catalysts offered producing nicotinonitrile from 3-methylpyridine with 93-95% mol. yield. Modifying of V-Ti catalysts by SnO<sub>2</sub> increased their activity. The reason is V=O bond weakening under the influence of SnO<sub>2</sub>. That was verified by increasing of V<sub>2</sub>O<sub>5</sub> dissociation rate almost by an order in comparison with V-Ti catalysts. SnO<sub>2</sub> in the ternary catalysts exists as individual phase and acts as a donor of oxygen for the lower vanadium oxides. It provides the high stability of V-Ti-Sn catalysts and possibility of obtaining isonicotinonitrile with 95-97% mol. yield from 4-methylpyridine. The investigation of the mutual influence of starting components in the ternary V-Ti-Zr catalysts showed that ZrO<sub>2</sub> prevented the polymorphous transformation from anatase into rutile. In its turn, anatase stabilized baddeleyite, which has a higher catalytic activity than ruffite. Taking into account the mutual influence of the components, it was able to prepare the selective V-Ti-Zr catalyst. It offered obtaining nicotininitrile from 3-methylpyridine with 92-96% mol. yield. </p>

Oxidative Ammonolysis of 4-Methylpyridine on Oxide Vanadium-Titanium-Zirconium Catalyst Modified by Tin and Tungsten Oxides

“…Vanadium-zirconium oxide catalysts showed high selectivity in the process of oxidative ammonolysis of 3-picoline [12,13]. We have previously shown that the oxide vanadium-titanium-zirconium catalyst exhibits high activity and selectivity in the oxidative ammonolysis of 4-methylpyridine, making it possible to obtain 4-cyanopyridine with a yield of 90-95% at a temperature of 260-270 °C and minimum consumption of ammonia [13].…”