CONTROL OF DEALKYLATION VS RING HYDROGENATION BY USE OF AMMONIA

Hydrotreating studies with propylbenzene as a model compound on a comm ercial NiMo/Al2O3 catalyst at 300-360 degrees C and 6.9 MPa showed tha t selectivity to ring hydrogenation vs dealkylation was increased by a ddition of ammonia at partial pressures up to 49 kPa, although overall activity decreased. Both reactions followed first-order kinetics. Sel ectivity was markedly increased at the lowest temperatures but again w as accompanied by the lowest overall activity. The poisoning effect of ammonia here is much greater than that previously observed an hydrode sulfurization of thiophene or hydrodeoxygenation of dibenzofuran under identical reaction conditions.