Hydrodenitrogenation of Acridine on MoO₃-Al₂O₃ Catalyst

Abstract

The hydrodenitrogenation of acridine on a pre-reduced MoO^3-Al2O^2- catalyst, as an appropriate, model reaction of residual oil, was studied to obtain mechanistic information. The study was carried out in a flow microreactor using xylene solutions containing 0.1-1.0 wt% acridine at temperatures of 200-350° C, total pressures of 25-145 atm, WHSV 10, and hydrogen flow rate of 30 //hr.
Acridine was easily hydrogenated to 9, 10-dihydroacridine even below 200° C. Dihydroacridine was also hydrogenated succesively to 1, 2, 3, 4, 4a, 9, 9a, 10-octahydroacridines and perhydroacridines, which was denitrogenated to dicyclohexylmethane (DCM) above 300° C (Fig.2). The activation energy for the formation of DCM was found to be 32. ° kcal/mol. The rate equation was expressed as
where, r is the rate of formation of DCM, and CpA and PH₂ are the partial pressures of perhydroacridines and hydrogen, respectively. k, KPA and KH₂ are constants. On the basis of the kinetics, it was found that the hydrogenation of acridine to perhydroacridines is in equilibrium at higher temperatures and the rate-determining step is the reaction of perhydroacridines with hydrogen molecule (Fig.9).