Hydroconversion of n-Alkanes and Decalin Over Bifunctional Pt/Mazzite Catalysts

Fajula, François; Boulet, Marc; Coq, Bernard; Rajaofanova, V.; Figuéras, F.; Courières, T. Des

doi:10.1016/s0167-2991(08)64429-8

Cited by 3 publications

(6 citation statements)

References 17 publications

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“…4) [20,63]. Corroborating results were reported by another research group [19,29], so that these results appear representative of the zeolite-based catalysts under discussion. Some of the corroborating data [19] are less useful for the present analysis, for the reported 2,3-DMB-to-2-MP yield ratios are well in excess of the thermodynamic equilibrium value (as calculated from data provided by Refs.…”

Section: Selectivity Differencessupporting

confidence: 60%

“…The predominant speculation regarding the higher DMB yield of the MAZ-type zeolites is that the yield is somehow intrinsically linked to the MAZ-type topology [19,20,29]. This can be investigated by analyzing the C 6 isomer composition of the adsorbed (zeolite) phase under typical n-C 6 hydroconversion conditions.…”

Section: Does Selectivity Relate To Pore Topology?mentioning

confidence: 99%

“…In the early 1990s, it was suggested that MAZ-type zeolites are inherently better suited than MOR-type zeolites for yielding high-octane pentane and hexane [18][19][20]. An equitable comparison between the performance of MAZand MOR-type zeolites turned out to be remarkably complicated, for the accessibility [21][22][23][24][25][26][27], density, and strength [7,28,29] of the Brønsted acid sites all appear critically dependent on the zeolite synthesis [23,[30][31][32][33][34] and modification [23,35,36] processes.…”

Section: Introductionmentioning

confidence: 99%

“…After nearly a decade of research, it was concluded that the improvement of MAZ-over MORtype zeolites was too small to merit commercialization of the former [29,37]. Probably as a result of the experimental complexity, the fundamental reasons for the manifestation [18,19] of significantly higher octane numbers obtained with MAZ-over MOR-type zeolites have never been elucidated.…”

Section: Introductionmentioning

confidence: 99%

“…Theoretically, if hexane is free to adsorb and desorb, it should simply hydroisomerize toward gas-phase thermodynamic equilibrium and there would be no significant differences between the selectivities of FAU-, MAZ-, and MOR-type zeolites. Surprisingly, the higher-branched hexane yield observed with the MAZ-type zeolites under discussion was reportedly obtained without any obvious impediment to hexane adsorption or desorption, using either light naphtha [18] or n-hexane [19,20] as feed. This raises the question if our previous analysis was somehow incomplete: Can the MAZ-type zeolite topology affect the hexane product slate in some other way, in the absence of a feed component with a higher boiling point?…”

Section: Introductionmentioning

confidence: 99%

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The selectivity of -hexane hydroconversion on MOR-, MAZ-, and FAU-type zeolites

Calero

Schenk

Dubbeldam

et al. 2004

Journal of Catalysis

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Analyses of a series of published n-hexane hydroisomerization product slates suggest that MAZ-type zeolites yield more dimethylbutane and less methylpentane than either FAU-or MOR-type zeolites. Molecular simulations do not corroborate the traditional view that these selectivity differences are specifically related to the MAZ-, FAU-, or MOR-type zeolite topology. A scrutiny of the literature indicates that reported variation in selectivity relates to a variation in the efficiency of the (de)hydrogenation function relative to the acid function. The FAU-type zeolite catalyst had the most efficient hydrogenation function. The efficiency of the hydrogenation function on the MAZ-type zeolite was low enough to significantly enhance the 2,3-dimethylbutane yield relative to the methylpentane yield, but not low enough to decrease the 2,2-dimethylbutane yield. The efficiency of the hydrogenation function on the MOR-type zeolite was low enough to do both. Only at a sufficiently high n-hexane hydroconversion does the catalyst with the most efficient hydrogenation function exhibit the highest dimethylbutane yield. This new perspective on the reported hexane hydroconversion selectivities suggests that a FAU-type zeolite catalyst with a highly efficient hydrogenation function is best suited for n-hexane hydroisomerization. The FAU topology has the highest porosity which should afford the highest activity without impairing selectivity.  2004 Elsevier Inc. All rights reserved.

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