Ring opening of decalin over zeolitesI. Activity and selectivity of proton-form zeolites

Kubička, David; Kumar, Narendra; Mäki‐Arvela, Päivi; Karinen, Reetta; Niemi, V.; Salmi, Tapio; Murzin, Dmitry Yu.

doi:10.1016/j.jcat.2003.10.027

Cited by 136 publications

(104 citation statements)

References 38 publications

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“…19,20 When the reaction was performed at lower temperatures (498 to 600 K), higher pressures and with some hydrogen present, it was reported that isomerization products were primary and ring opening products were secondary in the reaction scheme. 14,20 However, it was observed in the present work that various products representative of different possible reactions do show at very low reaction times and conversions, thus giving support to the view that reactions such as cracking, ring opening, ring contraction, isomerization and hydrogen transfer, are present initially in a significant proportion. Moreover, some of the reactions can be assigned a secondary role too.…”

Section: Resultssupporting

confidence: 80%

“…An example of the product distributions obtained with the different catalysts at 723 K is shown in Table 2. These products are consistent with the proposed mechanisms for decalin reaction on acidic catalysts 14,17,19,20 and could be arbitrarily grouped as representative of the main reactions.…”

Section: Resultssupporting

confidence: 76%

“…All these variations can be explained based on a relatively more important occurrence of cracking of side chains, ring opening and alkylation reactions, and support the view that they are favored against hydrogen transfer reactions when temperature is increased. 22 Then, with basis in these results and previous reports, 14,17,[19][20][21] it is possible to postulate a new set of overall reaction paths, which is shown in Figure 7. As shown by the yield curves in Figure 4, direct and subsequent hydrogen transfer would constitute an important set of reactions from the beginning of the reaction system.…”

Section: Resultsmentioning

confidence: 56%

“…In effect, it can be seen that the concentration profiles for cis-decalin decrease strongly and steadily as a function of reaction time, while those of trans-decalin show either a slightly increasing profile at the lowest reaction temperature of 673 K, or a slow decrease at 723 K. These different behaviors between the cis-and the trans-isomers were also observed by other authors. For example, Lai and Song 13 and Kubicka et al, 14 who studied the conversion of decalin over different zeolites at lower temperatures, from 473 to 573 K, reported similar results on pure Y zeolite. A study performed by Mostad et al 15 with a wider temperature range (603 to 733 K) over various zeolites, showed that if the reactant was cis-, trans-or a mixture of both isomers over Y zeolite at 603 or 665 K, the only product was trans-decalin and concluded that cis-decalin stereoisomerizes into trans-decalin; at 733 K they found that cis-decalin appeared in the products from trans-decalin conversion, but, more interestingly, they determined that the rate of cis-to trans-isomerization was about 6 to 10 times faster than the trans-to cis-isomerization.…”

Section: Resultsmentioning

confidence: 69%

“…23 In coincidence, aromatic selectivities of 35% 19 and initial molar selectivities of 0.791 20 were reported among products in the conversion of decalin over zeolitic catalysts at high reaction temperatures from 723 to 823 K. Other authors found very low yields, possibly due to the low reaction temperatures, below 623 K, or to the co-feeding of hydrogen in the reaction medium that might saturate intermediate olefins. 14,17 Hydrogen transfer was suggested a major reaction at temperatures higher than 623 K, leading to up to 40% of aromatics in the conversion of decalin over acidic catalysts loaded with metals such as Pt or Ir. 24 The impact of hydrogen transfer on aromatic yields was underlined by Sousa-Aguiar et al, 18 who associated the low concentration of olefins in the reaction medium to their consumption through these reactions, where naphthenes may play a donor role and convert themselves into aromatics.…”

Section: Resultsmentioning

confidence: 99%

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Yield of aromatics from naphthenics upon catalytic cracking

Pujro¹,

Falco²,

Pedrosa³

et al. 2012

J. Braz. Chem. Soc.

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Cis-e trans decalina foram submetidas à reação com catalisadores de craqueamento, para estudar a formação de aromáticos numa fração particular de produtos líquidos do processo de craqueamento catalítico fluido (FCC). Um reator batelada em leito fluidizado, CREC, foi usado a 673 e 723 K com tempos de contato entre 3 e 15 s. Cis-decalina foi muito mais reativa. Apesar de diferenças induzidas e medidas na acessibilidade dos catalisadores, seus perfis de atividade foram similares, sugerindo que restrições difusionais não prevalecem. Os produtos foram hidrocarbonetos C 1 -C 12 , enquanto o coque foi muito baixo. Reações de isomerização, craqueamento, transferência de hidrogênio, abertura/contração de anel e alquilação ocorreram, e produtos das várias reações foram observados em tempos de reação muito baixos. Naftênicos bicíclicos C 10 e aromáticos alquilsubstituídos C 7 -C 11 ou nafteno-aromáticos foram os produtos mais importantes. Um mecanismo de reação com três rotas iniciais (isomerização, abertura de anel e reações de transferência de hidrogênio) foi proposto.Cis-and trans-decalin were reacted over cracking catalysts to study the formation of aromatics in a particular fraction of the liquid products obtained in the fluid catalytic cracking process (FCC). A batch, fluidized bed CREC riser simulator reactor was used at 673 and 723 K and contact times varied from 3 to 15 s. Cis-decalin was much more reactive. Despite differences induced and measured in their accessibility indices, the catalysts led to similar activity profiles, suggesting that diffusion restrictions do not prevail. Products were C 1 -C 12 hydrocarbons while coke was very low. Isomerization, cracking, hydrogen transfer, ring opening, ring contraction and alkylation reactions occurred and products from the various reactions were observed at very short reaction times. Bicyclic C 10 naphthenics and alkyl-substituted C 7 -C 11 aromatics or naphtheno-aromatics were the most important products. A reaction mechanism with three initial routes (isomerization, ring opening and direct hydrogen transfer reactions) was proposed.

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Section: Resultssupporting

confidence: 80%

Section: Resultssupporting

confidence: 76%

Section: Resultsmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Yield of aromatics from naphthenics upon catalytic cracking

Pujro¹,

Falco²,

Pedrosa³

et al. 2012

J. Braz. Chem. Soc.

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Ring Opening of Aromatics

Weitkamp

2008

Handbook of Heterogeneous Catalysis

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The sections in this article are Introduction Fundamentals of Hydrodecyclization of Cycloalkanes Hydrogenolysis on Metals Hydrocracking on Bifunctional Catalysts Cracking and Activation of Hydrogen on Monofunctional Acidic Catalysts Ring Opening of Aromatics in Diesel and Jet Fuels Bifunctional Catalysts Metal Catalysts Acid Catalysts Ring Opening of Aromatics in Gasoline Without Degradation of the Carbon Number Ring Opening of Aromatics in Pyrolysis Gasoline Followed by Hydrocracking into a Synthetic Steam‐Cracker Feed Hydrodecyclization and Hydrocracking of Cycloalkanes on Acid Zeolites Direct Ring Opening of Aromatics on Bifunctional Zeolites Conclusions Acknowledgments

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Kinetic modeling of catalytic conversion of methylcyclohexane over USY zeolites: Adsorption and reaction phenomena

Al-Sabawi¹,

Lasa²

2009

AIChE Journal

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Catalytic conversion of cycloparaffins is a complex process involving competing reaction steps. To understand this process, FCC experiments using methylcyclohexane (MCH) on USY zeolite catalysts were carried out in the mini-fluidized CREC riser simulator. Runs were developed under relevant FCC process conditions in terms of partial pressures of MCH, temperatures (450-550 C), contact times (3-7 s), catalyst-oil mass ratios (5), and using fluidized catalysts. MCH overall conversions ranged between 4 to 16 wt %, with slightly higher conversions obtained using the larger zeolite crystallites. Moreover, it was found that MCH undergoes ring opening, protolytic cracking, isomerization, hydrogen transfer and transalkylation. A heterogeneous kinetic model for MCH conversion including thermal effects, adsorption and intrinsic catalytic reaction phenomena was established. Adsorption and kinetic parameters were determined, including the heat of adsorption (À40 kJ/mol), as well as thermal and primary catalytic intrinsic activation energies, which were in the range of 43-69 kJ/mol, and 50-74 kJ/mol, respectively. V

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Ring opening of decalin over zeolitesI. Activity and selectivity of proton-form zeolites

Cited by 136 publications

References 38 publications

Yield of aromatics from naphthenics upon catalytic cracking

Yield of aromatics from naphthenics upon catalytic cracking

Ring Opening of Aromatics

Kinetic modeling of catalytic conversion of methylcyclohexane over USY zeolites: Adsorption and reaction phenomena

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