Self-inhibition for HDN of quinoline, indole and carbazole over Ni-Mo catalyst in the presence of 4, 6-DMDBT

The hydrodenitrogenation (HDN) experiments of quinoline, indole and carbazole, respectively, in the 4, 6-DMDBT toluene solution with w(S) of 849 μg/g were carried out under the conditions of 280°C, total pressure 2 MPa, V(H2)/V(Oil)=300 and the liquid hourly space velocity 5 h-1, to investigate self-inhibition for HDN of the three nitrogen-containing compounds over Ni-Mo catalyst in the presence of 4, 6-DMDBT. According to the rate of HDN, the pathways of reaction and the change of products, quinoline had no self-inhibition effect for HDN, even the N mass fraction was 455 μg/g in the presence of 4, 6-DMDBT. The conversion of quinoline was 97% and the rate of HDN was 10%, which was the lowest in the three-containing compounds. The product of part hydrogenation of quinoline, tetrahydroquionline, had self-inhibition effect for HDN. In the range of N mass fraction used in this experiment, indole and carbazole both had self-inhibition effect for HDN, which was mainly from their part hydrogenation products, indoline and tetrahydrocarbazole, also the product of N alkyl substitution of indole, N-ethyl-indole. The self-inhibition effect for HDN of carbazole was lower than that of indole.