Hydrodenitrogenation of 2-methylpyridine and its intermediates 2-methylpiperidine and tetrahydro-methylpyridine over sulfided NiMo/γ-Al2O3

Wang, Huamin; Liang, Changhai; Prins, R.

doi:10.1016/j.jcat.2007.08.005

Cited by 12 publications

(9 citation statements)

References 33 publications

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“…H 2 S greatly enhanced the yield of C6 products and slightly reduced the 2-methylpyridine yield. The results are in agreement with those of Wang et al [26].…”

Section: Hdn Of 2-methylpiperidinesupporting

confidence: 94%

“…Breaking of the two C-N bonds occurs by addition of H 2 S to pentylimine, NH 3 elimination, and hydrogenation, as indicated in Scheme 2 and described for 2-methylpiperidine [26]. In the HDN of 2-methylpiperidine more 2-hexylamine than 1-hexylamine was produced, because the addition of H 2 S to the imine 2,3,4,5-tetrahydro-6-methylpyridine is sterically hindered and the addition of H 2 S to 2,3,4,5-tetrahydro-2-methylpyridine is not hindered [13,26]. For the same reason more 2-pentylamine than 1-pentylamine was observed in the HDN of 2-methylpyrrolidine.…”

Section: Discussionmentioning

confidence: 99%

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On the Formation of Pentylpiperidine in the Hydrodenitrogenation of Pyridine

Wang

Prins

2008

Catal Lett

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The hydrodenitrogenation of 2-methylpiperidine and 2-methylpyrrolidine was studied over sulfided NiMo/c-Al 2 O 3 in the presence of dialkylamines, alkylamines, and alkenes to determine why N-pentylpiperidine is formed in the hydrodenitrogenation of pyridine. N-alkylated 2-methylpiperidine and 2-methylpyrrolidine were only formed as primary products by reaction with alkylamines and not by reaction with 2-methylpiperidine and 2-methylpyrrolidine, or by reaction with an alkene. This indicates that, in the hydrodenitrogenation of pyridine, N-pentylpiperidine is formed by the reaction of the secondary intermediate pentylamine with the primary intermediate piperidine, and not by reaction of two primary piperidine intermediates or by reaction of pentene, one of the final products, with piperidine.

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“…H 2 S greatly enhanced the yield of C6 products and slightly reduced the 2-methylpyridine yield. The results are in agreement with those of Wang et al [26].…”

Section: Hdn Of 2-methylpiperidinesupporting

confidence: 94%

Section: Discussionmentioning

confidence: 99%

On the Formation of Pentylpiperidine in the Hydrodenitrogenation of Pyridine

Wang

Prins

2008

Catal Lett

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“…Zhao et al − found that over a sulfided NiMo/γ-Al 2 O 3 catalyst, C−N bond cleavage of an alkylamine occurred exclusively by nucleophilic substitution by H 2 S to form an alkanethiol. This substitution does not occur by a classic S N 2 substitution, but by a sequence of reactions in which the amine first dehydrogenates to an intermediate imine. , Recently, Wang et al studied the HDN of 2-methylpyridine and its intermediates, 2-methylpiperidine as well as tetrahydromethylpyridine, over a sulfided NiMo/γ-Al 2 O 3 catalyst. They considered the denitrogenation of 2-methylpiperidine to take place via substitution of 2-methylpiperidine to aminohexanethiols through imine intermediates.…”

Section: Discussionmentioning

confidence: 99%

Promoting Effect of TiO₂on the Hydrodenitrogenation Performance of Nickel Phosphide

Wang

et al. 2008

J. Phys. Chem. C

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TiO 2 -containing bulk Ni 2 P catalysts (Ti x -Ni 2 P) were prepared by coprecipitation and in situ H 2 temperatureprogrammed reduction (TPR), and characterized by XRD, CO chemisorption, TEM, XPS, TPR, and NH 3 -TPD. Their hydrodenitrogenation performances were studied by using quinoline and decahydroquinoline (DHQ) as the model molecules. Both the hydrogenation and C-N bond cleavage activities of Ni 2 P were improved by the introduction of TiO 2 . The TiO 2 species were mainly located separately on the surface of the catalysts and had strong interactions with surface Ni and P species. The reducibility of the precursors as well as the surface electronic properties of Ni 2 P catalysts were affected by the addition of TiO 2 . Ti x -Ni 2 P showed higher CO uptake but less acid sites than Ni 2 P. The promoting effect of TiO 2 was discussed by considering the electronic interactions between surface Ti and Ni 2 P species and changes in the adsorption geometries of quinoline, DHQ, as well as the partially hydrogenated intermediates over Ti x -Ni 2 P.

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“…Duan and Savage observed this side reaction between piperidine and pentylamine at a low temperature via the amine disproportionation reaction. 9 Wang and Prins 13 suggested that besides disproportionation of two piperidine molecules, the reaction between piperidine and pentene from pentylamine cannot be overlooked and the pentylamine concentration was vanishingly low since the reaction was too fast. Pentylamine was not detected in our experiment as well.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Catalytic Hydrodenitrogenation of Pyridine under Hydrothermal Conditions: A Comprehensive Study

Liu

Duan

et al. 2020

ACS Sustainable Chem. Eng.

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This article focuses on the kinetic modeling and catalytic performance of hydrodenitrogenation of pyridine under hydrothermal conditions. Piperidine derivatives are the major nitrogen-containing intermediates, including 1-piperidinecarboxaldehyde, 1-piperidineethanol, and alkyl piperidines. Catalysts overall improved the formation of N-free products including 1-pentanol and 2-methyl-1-pentanol. Commercial Pd/C provided the highest pyridine conversion rate at 350 °C, while the homemade Ni–Ru bimetallic catalyst provided a prominent denitrogenation activity at 400 °C, leading to the highest 1-pentanol yield as a major denitrogenated product. Conversion of pyridine over the Ni50Ru50/C catalyst led to formation of three major alkyl piperidines (1-ethyl piperidine, 1-methyl piperidine, and 1-pentyl piperidine). These alkyl piperidine intermediates could further be converted into amino and N-free compounds. A kinetic model was developed to mathematically describe the hydrothermal HDN reaction of pyridine over the Ni50Ru50/C catalyst, which clearly captured all data trends and fitted the temporal variation of all major products. Sensitivity analysis suggested that dehydrogenation from piperidine to pyridine has a strong impact on the whole reaction pathways.

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Hydrodenitrogenation of 2-methylpyridine and its intermediates 2-methylpiperidine and tetrahydro-methylpyridine over sulfided NiMo/γ-Al2O3

Cited by 12 publications

References 33 publications

On the Formation of Pentylpiperidine in the Hydrodenitrogenation of Pyridine

On the Formation of Pentylpiperidine in the Hydrodenitrogenation of Pyridine

Promoting Effect of TiO₂on the Hydrodenitrogenation Performance of Nickel Phosphide

Catalytic Hydrodenitrogenation of Pyridine under Hydrothermal Conditions: A Comprehensive Study

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Hydrodenitrogenation of 2-methylpyridine and its intermediates 2-methylpiperidine and tetrahydro-methylpyridine over sulfided NiMo/γ-Al2O3

Cited by 12 publications

References 33 publications

On the Formation of Pentylpiperidine in the Hydrodenitrogenation of Pyridine

On the Formation of Pentylpiperidine in the Hydrodenitrogenation of Pyridine

Promoting Effect of TiO2on the Hydrodenitrogenation Performance of Nickel Phosphide

Catalytic Hydrodenitrogenation of Pyridine under Hydrothermal Conditions: A Comprehensive Study

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Promoting Effect of TiO₂on the Hydrodenitrogenation Performance of Nickel Phosphide