Nitrogen bases resistant to hydrodenitrogenation: evidence against using quinoline as a model compound

Jokuty, Paula L.; Gray, Murray R.

doi:10.1021/ie00006a004

Cited by 13 publications

(16 citation statements)

References 7 publications

(9 reference statements)

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“…Moreover, in the latter study, the concentration of reactants was significantly lower. No results are available to compare other reactants with the low reactivity of diBzQ observed by Jokuty and Gray (28). Figure 12 further shows that at the short contact time, the reactivity of MeBzQ was the lowest.…”

Section: Hydrodenitrogenation Of Petroleummentioning

confidence: 93%

“…The studies of Jokuty and Gray (27,28) represent another example of the diversity of N-compounds. These authors separated the basic and nonbasic fractions from the hydrotreated gas oil derived from Athabasca bitumen by delayed coking.…”

Section: E Furimsky and F E Massothmentioning

confidence: 99%

“…7 confirmed that the HYD of the N-ring occurred before that of the aromatic ring. Jokuty and Gray (28) reported that the HDN of the N-ring -substituted diBzQ required the gradual HYD of aromatic rings followed by cracking until the substituted PYs were the last N-containing intermediates before the final HDN could be achieved. However, it was still too fast to be measured.…”

Section: Iii113 Acridinesmentioning

confidence: 99%

“…The study published by Jokuty and Gray (28) emphasized the importance of the number of aromatic rings fused with the N-ring of Q on the overall HDN. …”

Section: Iii113 Acridinesmentioning

confidence: 99%

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Hydrodenitrogenation of Petroleum

Furimsky¹,

2005

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A high level of hydrodenitrogenation (HDN) is required to achieve a desirable conversion of other hydroprocessing reactions. This results from a strong adsorption of nitrogen-containing compounds on catalytic sites that slows down the hydrogen activation process and hinders the adsorption of other reactants. Studies on model compounds and real feeds indicate that less than 50 ppm of nitrogen in the feed can poison catalytic sites. Kinetic studies determined adsorption constants of various nitrogen-containing compounds and concluded that at least four different catalytic sites are required to interpret experimental observations in contrast with a dual site site ffi concept, which only considered two sites. The advancements in experimental techniques allowed identification of products formed during very early stages of hydrodenitrogenation. These results confirmed that the removal of the amino group from saturated amines, as the last step in hydrodenitrogenation, is governed by the type of carbon to which the amino group is attached rather than the number of hydrogen atoms attached to carbon in a and b position to nitrogen Performance of conventional Co(Ni)Mo(W)/Al 2 O 3 catalysts during hydrodenitrogenation was enhanced by combination with various additives and by replacing the traditionally used g-Al 2 O 3 support with novel supports. Catalytic functionalities could be modified by using different precursors of active metals and varying conditions during preparation. Progress has been made in the development of catalysts possessing a high selectivity for hydrodenitrogenation. In this case, the nonconventional catalysts based on the carbides and nitrides of transition metals exhibited high activity and selectivity. Noble metal sulfides alone or supported on different supports were active for HDN as well. Feedstocks used for catalyst evaluation included model compounds and mixtures of model compounds as well as real feeds. The challenges in the development of catalysts for hydrodenitrogenation of heavy feeds containing asphaltenes and metals have been identified.In general, compared to Q, conversions were little affected by a methyl (Me) on the aromatic ring, while being lower for Me on the N-ring, except for 2-MeQ. It is evident that Me substitution in the 2-position had little effect on HDN over the NiMoP/Al 2 O 3 catalyst, whereas it actually enhanced the HDN rate over the CoMo/Al 2 O 3 catalyst. For both catalysts the HDN rate was suppressed in 6-MeQ and particularly in 3-MeQ and 4-MeQ. The distribution of N-containing intermediates was influenced by the ring substitution and the type of catalyst. This suggests that several factors influence the overall HDN mechanism of Qs. This should be kept in mind while analyzing differences in the networks proposed by different authors.The preceding discussion on the HDN of Q mostly referred to conventional catalysts. A number of studies on the HDN of Q were conducted over unconventional catalysts. For example, 3-and 4-MeQs were more reactive than Q over the unsupported Zr,...

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Section: Hydrodenitrogenation Of Petroleummentioning

confidence: 93%

Section: E Furimsky and F E Massothmentioning

confidence: 99%

Section: Iii113 Acridinesmentioning

confidence: 99%

“…The study published by Jokuty and Gray (28) emphasized the importance of the number of aromatic rings fused with the N-ring of Q on the overall HDN. …”

Section: Iii113 Acridinesmentioning

confidence: 99%

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Hydrodenitrogenation of Petroleum

Furimsky¹,

2005

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“…The numbers next to the arrows are pseudorate constants at 375"C, 6.9 MPa in units of mol/g cata1yst.s x lo5. (b) reaction pathways for catalytic hydrogenation of pyridine benzologs (after Jokuty and Gray, 1992). THBQ = tetrahydro benzoquinoline; OHBQ = octahydro benzoquinoline; THBQ = tetrahydro benzoquinoline; OHBQ = octahydro benzoquinoline; THQ = tetrahydroquinoline.…”

Section: Model Compoundsmentioning

confidence: 99%

Through a glass, darkly: Kinetics and reactors for complex mixtures syncrude innovation award lecture

Gray

1997

Can J Chem Eng

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The concepts of chemical reaction engineering are powerful, because the most basic design equations are applicable to a wide range of physical phenomena. For example, the applicability of the ideal continuous-flow stirred tank reactor goes far beyond chemical reactors to include biological, medical and environmental processes. The difficulty in analyzing these processes is not in formulating an appropriate reactor equation, but in modeling the chemical kinetics. The challenge is to define kinetic rate equations that allow for the mixtures of reactants and mixtures of catalysts, especially given incomplete information. Examples drawn from biology and medicine illustrate reaction kinetics that are complex due to the nature of the catalyst.In contrast, processes for upgrading of bitumen to more valuable products exhibit ill-defined reaction chemistry and mixtures of thousands of reactants and products. The need to define kinetics for such mixtures has given rise to several distinct approaches, including empirical rate equations, simplification to model reactions, lumped kinetics and Monte Carlo simulation. A summary of these methods shows that the key element for successful kinetic modeling is creative definition of a model, followed by vigorous testing of the model to determine its ability to predict performance. chemical and chemical processes illustrate that the practice of kinetics inevitably involves dealing with complex mixtures, complex catalysts, or both simultaneously. The art in the practice of chemical kinetics lies in balancing the need for fundamental understanding of the variables that influence the reactions, on the one hand, with the need to get the job done to support the overall work of development of chemical processes. Objective of chemical reaction engineeringChemical kinetics is only one component of the larger field of chemical reaction engineering, which seeks to design reactors for safe and efficient manufacture of products of desired purity. Large-scale manufacturing favors continuous or semi-continuous operation over batch processes; therefore, the core intellectual discipline of chemical reaction engineering is the analysis of chemical reactions in open systems, where mass enters and leaves the reactor vessel simultaneous to the chemical transformation. This discipline is unique to the education and practice of chemical engineers, who can also use this approach to make a unique contribution wherever reactions occur in open systems, ranging from medicine and biology to the environment.

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