Bifunctional Mechanism of Pyridine Hydrodenitrogenation

Article abstract of DOI:10.1006/jcat.1995.1252

The role of Mo coordinatively unsaturated sites (CUS) and Broensted acidic sites in the hydrodenitrogenation of pyridine was investigated in an atmospheric-pressure microreactor.The test catalysts consisted of nonsulfided Mo oxide supported on Al2O3, SiO2, and silica-aluminas, containing different concentrations of Mo CUS and Broensted acidic sites.The kinetic study revealed that Mo loading and support composition affect the specific activity of Mo and selectivity of the catalysts.For the range of conditions used in this study (360-420 deg C, 1 atm H2, 0.2 molpercent pyridine concentration, differential conversion), the most abundant reaction intermediate was trans-2-pentene, and the rate-limiting step was the hydrogenation of the ring.Thus, the overall activity was correlated with the concentration of Mo CUS, which are the hydrogenation sites.The yield of denitrogenated product was also correlated with concentration of CUS.The Broensted acidic sites determined the selectivity towards the observed cracking, isomerization, and alkylation products.