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Houžvička, J.; Klik, R.; Kubelková, Ludmila; Ponec, V.

doi:10.1023/a:1018930320503

Cited by 19 publications

(16 citation statements)

References 10 publications

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“…Because all samples have similar total acid amounts, they also have similar initial C n . It is known that side reactions, such as bimolecular and secondary reactions, are more likely to occur at sites with higher acid densities or strong acids . Therefore, the high C n and low selectivity of isobutene( S i ) in the initial stage of the reaction are due to the simultaneous occurrence of unimolecular, bimolecular, and secondary reactions in the FER channels.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…It is known that side reactions, such as bimolecular and secondary reactions, are more likely to occur at sites with higher acid densities or strong acids. [28][29][30] Therefore, the high C n and low selectivity of isobutene(S i ) in the initial stage of the reaction are due to the simultaneous occurrence of unimolecular, bimolecular, and secondary reactions in the FER channels. However, the final C n decreases significantly with an increase in (NH 4 ) 2 SiF 6 concentration (Figure 7).…”

Section: Catalytic Properties and Analysis Of Effective Active Sitesmentioning

confidence: 99%

“…(NH 4 ) 2 SiF 6 treatment has a minor effect on the acid sites in the FER channels; thus, the high final S i of all samples is due to the effect of carbon deposition, which effectively suppresses the side reactions. [28][29][30] The decrease in S i and the increase in the selectivity of propene pentene(S p ) of FER-0.8 may be ascribed to the damage of the pore structure caused by excessive dealumination, which may affect its shape selectivity; the increase of proportion of L acid amount also leads to the aggravation of the cracking reaction.…”

Section: Catalytic Properties and Analysis Of Effective Active Sitesmentioning

confidence: 99%

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Distribution of Effective Ferrierite Active Sites for Skeletal Isomerization of n‐Butene to Isobutene

Liu

et al. 2019

ChemistrySelect

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In this study, the effective active sites of aged ferrierite(FER) were confirmed to be located in the 10‐membered ring (10‐MR) pore mouths by modification with ammonium hexafluorosilicate((NH4)2SiF6 )and long‐term experiments. Analysis of SiO2/Al2O3 ratios showed that aluminum atoms were selectively removed from the FER surface after the modification with (NH4)2SiF6. Comparison of the catalytic properties before and after modification showed that the catalytic activity of aged FER depended only on the amount of acid sites located in the 10‐MR pore mouths. Monitoring of the change in acid amount with reaction time and the difference between aged and deactivated FER showed that aged FER retained only weak acid sites, and its deactivation was caused by carbon deposition on the 10‐MR pore mouth acid sites. Therefore, the catalytic performance of FER can be improved by increasing the number of 10‐MR pore mouths.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Catalytic Properties and Analysis Of Effective Active Sitesmentioning

confidence: 99%

Section: Catalytic Properties and Analysis Of Effective Active Sitesmentioning

confidence: 99%

See 2 more Smart Citations

Distribution of Effective Ferrierite Active Sites for Skeletal Isomerization of n‐Butene to Isobutene

Liu

et al. 2019

ChemistrySelect

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“…Subsequently, the iso-butene is hydrogenated to iso-butane. The formation of <C3, C3, and C5 proceeds through dimerization of C4 followed by cracking (44). The dimerization of C4 also gives rise to oligomerization, resulting in coking of the catalysts and the observed initial deactivation.…”

Section: Hds Activity and Product Selectivitymentioning

confidence: 99%

Influence of Si/Al Ratio on Catalytic Performance of (Co)Mo/Saponite Catalysts

Leliveld

Ros

Dillen

et al. 1999

Journal of Catalysis

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The influence of the Si/Al ratio of the support of (Co)Mo/saponite catalysts on the performance in the hydrodesulfurisation of thiophene and hydrocracking of n-decane has been studied. The initial thiophene HDS activity of the sulfided Co catalysts increased with increasing support acidity, while with the CoMo catalysts the opposite effect was observed. The large drop in activity at lower Si/Al ratios is ascribed to the occurrence of two separate cobalt and molybdenum sulfide phases instead of the "Co-Mo-S" phase. In the hydrocracking of n-decane both the Co and the CoMo catalysts displayed an almost linear relationship between the first-order rate constant and the number of Brønsted acid sites. As with zeolite catalysts the Si/Al ratio was also found to affect the product selectivity. At low Si/Al ratios the relative amount of secondary cracking products increased due to a changing balance between the number of cracking and hydrogenation sites. Remarkably, it was found that in the presence of H 2 S between 423 and 573 K the n-decane conversion passes through a maximum. The observed relation between this "low-temperature" activity and the number of Brønsted acid sites seem to indicate the involvement of both H 2 S and the acid sites on the support.

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