Attempts to rationalize the distribution of hydrocracked products. III. mechanistic aspects of isomerization and hydrocracking of branched alkanes on ideal bifunctional large-pore zeolite catalysts

Martens, Johan A.; Tielen, Mia; Jacobs, Peter A.

doi:10.1016/0920-5861(87)80008-1

Cited by 53 publications

(45 citation statements)

References 6 publications

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“…On the basis of the hydrocracking mechanism (39,44,45) (Figs. 3-5), it is possible to link the individual components of the primary C 10 hydrocracking product slate (Table 2 …”

Section: Resultsmentioning

confidence: 99%

“…It has been shown that n-C 7 and n-C 10 share essentially the same hydroconversion mechanism (37,39,44,45,46). The only difference between n-C 7 and n-C 10 is that the latter can hydroisomerize into a tribranched "iii-C 10 " isomer with both geminal and quasi-vicinal methyl groups (i.e., with methyl groups on α,α,γ positions) (39, 44-48) before hydrocracking, whereas the former is too short to form the equivalent iii-C 7 hydrocracking precursor.…”

Section: Resultsmentioning

confidence: 99%

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Differences between MFI- and MEL-Type Zeolites in Paraffin Hydrocracking

Maesen¹,

Schenk

Vlugt

et al. 2001

Journal of Catalysis

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A critical evaluation of published paraffin hydroconversion data shows that MEL-type zeolites preferentially hydrocrack paraffins where two methyl groups are separated by a methylene group, whereas MFI-type zeolites prefer paraffins with geminal methyl groups (preferably at the central carbon atom). Due to this difference in hydrocracking pathway, MEL-type zeolites will hydroisomerize a higher percentage of the feed than MFI-type zeolites at low temperature, while the reverse is true at high temperature. The free energies of adsorption calculated by means of configurational bias Monte Carlo (CBMC) molecular simulations are used to explain these differences in selectivity. They show that the MEL-and MFI-type zeolites favor the formation and hydrocracking of the dimethyl paraffins that have a shape commensurate with that of their pores. They indicate that the higher paraffin hydroisomerization selectivity of the MEL-type zeolites can also be explained by their higher selectivity for adsorbing linear rather than branched paraffins at high paraffin loading. At low paraffin loading this difference in adsorption selectivity disappears. Both temperature and loading effects could resolve a disparity in the literature between n-decane and n-heptane hydroisomerization selectivity data.

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“…On the basis of the hydrocracking mechanism (39,44,45) (Figs. 3-5), it is possible to link the individual components of the primary C 10 hydrocracking product slate (Table 2 …”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Differences between MFI- and MEL-Type Zeolites in Paraffin Hydrocracking

Maesen¹,

Schenk

Vlugt

et al. 2001

Journal of Catalysis

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“…For instance the complete integration of the isomerization and the separation sections in a single (in situ adsorption or the use of membranes for in situ separation) reactor [64] and the co-processing of C 5-6 hydrocarbons with C 7 (the latter challenge, based on the great activity difference between C 5-6 and C 7 hydrocarbons is well illustrated in Fig. 4 favored reaction [67,68]. Isomerization of light naphtha, especially C 5 's, will probably be reduced in the near future because of the blending of bio-ethanol with gasoline.…”

Section: -6 Paraffins Hydro-isomerizationmentioning

confidence: 99%

Impact of Zeolites on the Petroleum and Petrochemical Industry

2009

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The general features of zeolites that led to their widespread use in oil refining and petrochemistry are highlighted as well as the details of their impact on selected processes. The analysis of the catalyst market and the position of zeolites therein is a good indication of their strategic importance. Zeolites have brought many disruptive changes to these fields (e.g. FCC). They impacted also these industries in an equally important way, although more subtle, by incremental improvement of processes. The new and vast challenges facing oil refining and petrochemistry as well as the managed transition to sustainable environmental benign transport fuel industries and chemical industries will require creative science and technologies. Zeolites offer the basis of many of these technological solutions provided efficient and balanced cooperations between industry and academia are further developed.

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“…It is well known that in the isomerization of linear alkanes the fraction of multibranched isomers in the equilibrium decreases with increasing temperature [52]. It can be seen in Fig.…”

Section: Influence Of Acid Site Density (Si/al Ratio) and Crystallitementioning

confidence: 83%

Comparison of Large Pore Zeolites for n‐Octane Hydroisomerization: Activity, Selectivity and Kinetic Features

Chica¹,

Corma²

2007

Chemie Ingenieur Technik

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Dedicated to Professor Dr.-Ing. J. Weitkamp on the occasion of his 65th birthdayThe hydroisomerization of n-octane has been catalyzed by different zeolitic structures with large pore size (12 MR). It has been seen that channel topology, chemical composition, crystal size, and adsorption properties are of paramount importance for improving the isomerization activity and selectivity. Nanocrystalline beta zeolite (30 nm) with large pore size (0.66 × 0.67 and 0.56 × 0.56 nm), and high aluminum content (Si/Al = 16), was the best catalyst to produce multibranched isomers. Cracking reactions also occur together with isomerization and the product distribution will depend on the rate constant and relative activation energies of isomerization, desorption, and cracking. Furthermore, a complete kinetic study of n-octane isomerization has been carried out with beta zeolite, and kinetic rate constants, heats of adsorption, and activation energies have been determined for each individual isomerization step. The rate of isomerization of n-octane to monobranched products was found to be faster than the rate of cracking of dibranched products and the rate of isomerization of mono-to dibranched products. It should be possible to obtain high yields of dibranched alkanes by distillation and recycling units, or by using membrane reactors.

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Attempts to rationalize the distribution of hydrocracked products. III. mechanistic aspects of isomerization and hydrocracking of branched alkanes on ideal bifunctional large-pore zeolite catalysts

Cited by 53 publications

References 6 publications

Differences between MFI- and MEL-Type Zeolites in Paraffin Hydrocracking

Differences between MFI- and MEL-Type Zeolites in Paraffin Hydrocracking

Impact of Zeolites on the Petroleum and Petrochemical Industry

Comparison of Large Pore Zeolites for n‐Octane Hydroisomerization: Activity, Selectivity and Kinetic Features

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