The role of deposits in butene isomerisation

Houžvička, J.; Hansildaar, S.; Nienhuis, J.G.; Ponec, V.

doi:10.1016/s0926-860x(98)00235-x

Cited by 29 publications

(27 citation statements)

References 14 publications

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“…Once the deposits were totally converted to unreactive species, the intrinsic high selectivity of the H-FER was recovered. Note that the current proposal on the role of aromatics formation differs significantly from that of the role of coke reported in other studies (4,(10)(11)(12)(13)(14), in which coke was suggested to hinder oligomers formation by restricting pore dimension or blocking unselective acid sites. On the contrary, our experimental findings strongly support the model recently reported by de Jong et al (8).…”

Section: Relation Between the Carbonaceous Deposits And The Catalyticcontrasting

confidence: 95%

“…The selectivity to isobutene increased over a period of more than 100 min, whereas the signal associated with the polyenic species essentially reached a steady level in less than 20 min. Therefore, it is tempting to conclude that such rapidly formed deposits could be involved in the unselective cracking reactions (8,10,35).…”

Section: Relation Between the Carbonaceous Deposits And The Catalyticmentioning

confidence: 99%

“…Guisnet et al suggested that the isobutene yield was related to the formation of aromatic (5) or tert-butyl (9) carbocations, which catalyzed butene isomerization via a pseudomonomolecular mechanism. However, other authors proposed that the main role of these deposits was to deactivate nonselective sites and/or to increase steric constraint within the microporous solid (4,(10)(11)(12)(13)(14). De Jong et al recently proposed yet another model, in which reactive aliphatic carbonaceous deposits initially yield by-products before being converted to more inert aromatics (8).…”

Section: Introductionmentioning

confidence: 99%

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In Situ IR Study of the Nature and Mobility of Sorbed Species on H-FER during But-1-ene Isomerization

Meunier

Domokos

Seshan

et al. 2002

Journal of Catalysis

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The sorption and reaction of but-1-ene over a ferrierite sample was studied by in situ IR spectroscopy to relate the selectivity to isobutene and the sorbed species. The spectra highlighted the presence of various unsaturated species including polyenes, which were readily formed upon contacting H-FER with but-1-ene while a poor selectivity to isobutene was observed. Aromatic compounds were concluded to be subsequently formed via dehydrogenation/cyclization of the polyenic deposits while the isobutene selectivity increased via suppression of by-products. These data support earlier assumptions that the initial high yield of by-products was produced by the reaction of butenes with reactive deposits, which were gradually converted into more inert aromatic deposits. Upon purging the catalyst with an inert, branched C 8 hydrocarbons and aromatic molecules such as xylenes desorbed. The rates of desorption showed an initially linear variation with the square root of time and were fitted to a monodimensional Fickian model. Because the slowly diffusing species were rather abundant during the course of the reaction, it is proposed that the skeletal isomerization was effectively limited to the acid sites close the pore mouth of H-FER crystallites. c 2002 Elsevier Science (USA)

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Section: Relation Between the Carbonaceous Deposits And The Catalyticcontrasting

confidence: 95%

Section: Relation Between the Carbonaceous Deposits And The Catalyticmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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In Situ IR Study of the Nature and Mobility of Sorbed Species on H-FER during But-1-ene Isomerization

Meunier

Domokos

Seshan

et al. 2002

Journal of Catalysis

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“…Na-[Fe]ZSM5 was prepared using methods previously described [27]. [Fe]ZSM5 was treated in flowing dry air (0.4 cm 3 /(g s)) at 723 K for 15 h to remove organic templates used in its synthesis.…”

Section: Catalyst Synthesis and Characterizationmentioning

confidence: 99%

Catalytic dehydrogenation of alkanes on Pt/Na-[Fe]ZSM5 and staged O2 introduction for selective H2 removal

Waku

Biscardi

Iglesia

2004

Journal of Catalysis

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“…Isomerization of n-butene takes place on acidic catalysts. Zeolite catalysts with 10 memberred rings (E.g., H-ZSM-5 and H-Ferrierite) have been shown to have high selectivity toward isobutene (Byggninsbacka et al, 1997, Seo et al, 1996, Houzvicka et al, 1999. Their catalytic behaviors are highly dependent on the pore topology, acid strength, acid density and the location of the acid sites.…”

Section: Introductionmentioning

confidence: 99%

HZSM-5 and H-Ferrierite Acidity Modification by Silylation and Their Activities in n-Butene Isomerisation

Kılıç¹

2010

International Journal of Chemical Reactor Engineering

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H-ZSM5 and H-Ferrierite acidities were modified by chemical liquid deposition using tetraethylorthosilicate (TEOS), silicontetratchloride (SiCl 4 ) and triaminopropyltriethoxysilane (3-APTES). All depositions were carried out at room temperature for deposition times of 0.5 and 1 h. Reaction tests were performed in a tubular quartz fixed bed reactor at 375• C for weight hour space velocities of 22 h-1. Surface area and pore volume of the catalysts were decreased upon modifications. The least modification of acidity was achieved by TEOS. However, SiCl 4 and 3-APTES deposition modification strongly decreased the number of Bronsted and Lewis acid sites. As the effect of the modification increased, total acidity of the SiCl 4 modified catalyst decreased. The catalysts were tested in isomerization of n-butene. Modification decreased the activity of the catalysts, but improvement in selectivity was observed with TEOS deposition. TEOS deposition increased the selectivity of the catalysts; for synthesized H-ZSM5 from 57.95 to 63.74 percent, for commercial H-ZSM5-C from 26.78 to 32.52 percent, and for H-FER from 63.06 to 81.23 percent. However, modification with SiCl 4 and 3-APTES decreased both conversion and selectivity of the parent catalysts.

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The role of deposits in butene isomerisation

Cited by 29 publications

References 14 publications

In Situ IR Study of the Nature and Mobility of Sorbed Species on H-FER during But-1-ene Isomerization

In Situ IR Study of the Nature and Mobility of Sorbed Species on H-FER during But-1-ene Isomerization

Catalytic dehydrogenation of alkanes on Pt/Na-[Fe]ZSM5 and staged O2 introduction for selective H2 removal

HZSM-5 and H-Ferrierite Acidity Modification by Silylation and Their Activities in n-Butene Isomerisation

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