This study focuses on mechanism and kinetics in catalytic hydrodenitrogenation(HDN) of quinoline under hydrothermal conditions (300, 350 and 400°C), in which 30% Ni-Ru/γ-Al2O3 serves as catalyst and formic acid(FA) is used for in-situ H2 generation. The major products were 1,2,3,4 tetrahydroquinoline, dehydroquinoline, aniline, methyl aniline, 2-hexene, toluene. The quinoline conversion rate followed first-order kinetics, and the activation energy was 41.72 kJ/mol. A kinetic model based on the reaction network of hydrodenitrogenation of quinoline clearly captures all of the trends in the data and fits the temporal variation of all major products. Results reveal that 1,2,3,4-tetrahydroquinoline→dehydroquinoline→2-hexene is the main quinoline HDN route. Reaction rate analysis illustrates deamination is the main denitrogenation pathway. Sensitivity analysis demonstrated that the production of aniline derivatives inhibits yield of quinoline derivatives. TEM characterization indicates that nickel and ruthenium metal are uniformly distributed on the supporter, which was confirmed by XRD and XPS characterization as well.

This article focuses on the catalytic hydrodenitrogenation (HDN) mechanism of indole under hydrothermal conditions. Both gaseous hydrogen and liquid hydrogen donor formic acid (FA) can improve indole conversion and total yield of denitrogenated products. Ru/C showed the highest activity among the catalysts for indole conversion in all temperature conditions with the existence of H2 and 91.17 % indole was converted at 400 °C and 60 min. Based on reaction kinetic experiments, a kinetic model was developed to describe the hydrothermal HDN reaction of indole over the home-made Ni80Ru20/γ-Al2O3 catalyst, which clearly captured all data trends and fitted the temporal variation of all major liquid products. High activation energy for formation of O-containing substance o-cresol from both mathematical fitting and density functional theory (DFT) calculation indicated a rare occurrence of reaction between pyrrole ring-opening product methyl aniline and H2O, consistent with experimental observation that only a trace of o-cresol was detected.