Interaction of kinetics and internal diffusion in complex catalytic three-phase reactions: Activity and selectivity in citral hydrogenation

Aumo, Jeannette; Wärnå, Johan; Salmi, Tapio; Murzin, Dmitry Yu.

doi:10.1016/j.ces.2005.07.036

Cited by 25 publications

(20 citation statements)

References 8 publications

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“…[1][2][3][4][5][6][7] They are often carried out in semibatch autoclaves under elevated pressure with powdered catalysts. The efficiency of these processes is strongly dependent not only on the catalysts' intrinsic activity and selectivity but also on the interaction of mass/heat transfer with the chemical kinetics.…”

Section: Introductionmentioning

confidence: 99%

Three-Phase Catalytic Hydrogenation of a Functionalized Alkyne: Mass Transfer and Kinetic Studies with in Situ Hydrogen Monitoring

Bruehwiler¹,

Semagina²,

Grasemann³

et al. 2008

Ind. Eng. Chem. Res.

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Systematic studies of mass transfer interactions with intrinsic reaction kinetics were performed for the threephase selective hydrogenation of 2-methyl-3-butyn-2-ol (MBY) to 2-methyl-3-buten-2-ol (MBE) over a modified Pd/CaCO 3 catalyst under solvent free conditions. Hydrogen concentration in the liquid phase (C H2,b ) was monitored in situ during the catalytic reaction by means of the "Fugatron" analyzer. Reactions were carried out in an autoclave at different stirring rates at two concentrations of hydrogen (5 and 13 mol · m -3 ). For stirring speeds higher than 1500 rpm no influence of gas-liquid mass transfer was observed. Hydrogen liquid-solid (L-S) mass transfer was found to be negligible, whereas the MBY mass L-S transfer becomes important at high MBY conversions at high hydrogen concentration. Low stirrer speed caused the reaction rate and MBE selectivity to decrease. No internal mass transfer limitations were observed, and conditions for the kinetic regime were found. The kinetics modeled followed the Langmuir-Hinshelwood mechanism and was consistent with the experimental data.

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Section: Introductionmentioning

confidence: 99%

Three-Phase Catalytic Hydrogenation of a Functionalized Alkyne: Mass Transfer and Kinetic Studies with in Situ Hydrogen Monitoring

Bruehwiler¹,

Semagina²,

Grasemann³

et al. 2008

Ind. Eng. Chem. Res.

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“…[1][2][3][4] Several systematic studies on citral selective hydrogenation have been reported. These studies covered almost all important aspects such as active metals including mono-catalysts 2,[5][6][7][8][9][10][11] and the roles of catalyst supports. [12][13][14][15] Specifically, Yilmaz et al 12 reported the highest selectivity (90%) to citronellal so far, at complete conversion of citral over Pd/natural zeolite, which was explained by the active metal properties and the absence of significant internal diffusion limitations.…”

Section: Introductionmentioning

confidence: 99%

Selective Hydrogenation of Citral over a Carbon-titania Composite Supported Palladium Catalyst

Zhu

et al. 2011

Chin. J. Chem.

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A novel carbon-titania composite material, C/TiO 2 , has been prepared by growing carbon nanofibers (CNFs) on TiO 2 surface via methane decomposition using Ni-Cu as a catalyst. The C/TiO 2 was used for preparing supported palladium catalyst, Pd/C/TiO 2 . The support and Pd/C/TiO 2 catalyst were characterized by BET, SEM, XRD and TG-DTG. Its catalytic performance was evaluated in selective hydrogenation of citral to citronellal, and compared with that of activated carbon supported Pd catalyst. It was found that the Pd/C/TiO 2 catalyst contains 97% of mesopores. And it exhibited 88% of selectivity to citronellal at citral conversion of 90% in citral hydrogenation, which was much higher than that of activated carbon supported Pd catalyst. This result may be attributed to elimination of internal diffusion limitations, which were significant in activated carbon supported Pd catalyst, due to its microporous structure.

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“…The diffusion fl ux of reactants could be expressed as Equation (7), then derivative of Equation (7) and we had Equation (8). (7) (8)…”

Section: Diffusion-reaction Model Descriptionmentioning

confidence: 99%

“…Through the reaction-diffusion model, one can get the information about temperature and concentration gradients and judge if there is a dead zone in the catalyst particle. Scholars put great effort to the study of reaction-diffusion process and developed many different models based on different assumptions [5][6][7][8][9] . Although the two-dimensional mathematical model can describe both the axial and radial diffusion-reaction process of cylinder catalyst…”

Section: Introductionmentioning

confidence: 99%

One-dimensional isothermal multicomponent diffusion-reaction model and its application to methanol synthesis over commercial Cu-based catalyst

Lei

Zhang

et al. 2015

Polish Journal of Chemical Technology

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The present work was a study on global reaction rate of methanol synthesis. We measured experimentally the global reaction rate in the internal recycle gradientless reactor over catalyst SC309. The diffusion-reaction model of methanol synthesis was suggested. For model we chose the hydrogenation of CO and CO 2 as key reaction. CO and CO 2 were key components in our model. The internal diffusion effectiveness factors of CO and CO 2 in the catalyst were calculated by the numerical integration. A comparison with the experiment showed that all the absolute values of the relative error were less than 10%. The simulation results showed that decreasing reaction temperature and catalyst diameter were conducive to reduce the infl uence of the internal diffusion on the methanol synthesis.

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Interaction of kinetics and internal diffusion in complex catalytic three-phase reactions: Activity and selectivity in citral hydrogenation

Cited by 25 publications

References 8 publications

Three-Phase Catalytic Hydrogenation of a Functionalized Alkyne: Mass Transfer and Kinetic Studies with in Situ Hydrogen Monitoring

Three-Phase Catalytic Hydrogenation of a Functionalized Alkyne: Mass Transfer and Kinetic Studies with in Situ Hydrogen Monitoring

Selective Hydrogenation of Citral over a Carbon-titania Composite Supported Palladium Catalyst

One-dimensional isothermal multicomponent diffusion-reaction model and its application to methanol synthesis over commercial Cu-based catalyst

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