Pyridine hydrodenitrogenation: An equilibrium limitation on the formation of piperidine intermediate

Abstract

Abstract Equilibration between pyridine and piperidine, the first product formed in the overall series of hydrodenitrogenation (HDN) reactions of pyridine, can be a rate‐limiting factor under some conditions. Thus, on a commercial NiMo/Al 2 O 3 catalyst at 11 bars pressure, a maximum in the pyridine HDN rate occurs at about 400°C, caused by a thermodynamic limitation on the allowable concentration of piperidine. From studies with pyridine and with piperidine, NiMo/Al 2 O 3 appears to have greater hydrogenation‐dehydrogenation activity than CoMo/Al 2 O 3 but CoMo/Al 2 O 3 appears to have greater hydrogenolysis activity than NiMo/Al 2 O 3 , at least at about 300°C and below.