Tungsten and rhenium as hydrogenation agents in the hydrodenitrogenation of pyridine using stacked bed catalyst systems

This study analyses the hydrodenitrogenation (HDN) of pyridine using a stacked bed catalyst system, composed of a first hydrogenating bed of Re/γ-Al₂O₃ or W/γ-Al₂O₃, over a second bed of Ni-Re/γ-Al₂O₃ (HDN bed). Using potentiometric methods, it can be seen that the Re/γ-Al₂O₃ shows higher acidic strength than the W/γ-Al₂O₃. The results show that higher activity levels are obtained working with stacked bed systems compared to the separate catalysts. These results suggest that the incorporation of the catalyst Re/γ-Al₂O₃ or W/γ-Al₂O₃ beds would favour the formation of hydrogenated intermediary products, facilitating the removal of N-containing molecules via HDN on the Ni-Re/γ-Al₂O₃ catalyst.