Participation of acidic sites on catalyst in hydrodenitrogenation of quinoline

Quinoline, tetra- and deca-hydroquinolines, o-propylaniline, and 2-methylcyclohexylamine were allowed to react under hydrogen over the catalysts containing nickel with different acidic properties to elucidate the role of acidic sites in hydrodenitrogenation of quinoline. The acidic properties were measured by temperature-programmed desorption of ammonia. The step in which the acidic sites participate is the cleavage of the C–N bond connecting NH2 group to cyclohexyl ring. This step is the final step in hydrodenitrogenation of quinoline to form hydrocarbons and ammonia. A combination of metallic components which promote hydrogenation and dehydrogenation with acidic sites which cleave the C–N bond is important for a highly active catalyst for hydrodenitrogenation.