気相不均一系におけるピリジンの直接アミノ化触媒

抄録

Catalysts consisting of three different metaloxides were effective in activating the direct amination reaction of pyridine by ammonia in the heterogeneous vapor-phase. The cobalt oxide catalyst supported by silica magnesia exhibited the greatest activity for amination. 2-Aminopyridine and hydrogen were formed as the main products of the desired reaction. On the other hand, pyridine-N-oxide, water, and carbon dioxide, which were obtained simultaneously, were found to be the by-products. From a catalyst containing 10 wt% of cobalt, and supported by 80 wt% silica gel-containing silica magnesia, 2-aminopyridine was obtained initially at a yield of ∼11% at 450°, and formed at a yield of 5.5% at 50 hours after the beginning of the reaction. However, the yield of 2-aminopyridine decreased if the reaction temperature rose above 500° due to the decomposition of 2-aminopyridine. Finally, the direct catalytic amination reaction of α-picoline, β-picoline, and γ-picoline by ammonia confirmed the formation of the respective aminopicolines.