Preparation of Pt/γ-Al2O3Pellets with Internal Step-Distribution of Catalyst: Experiments and Theory

Papageorgiou, Panayiotis; Price, Douglas M.; Gavriilidis, Asterios; Varma, Arvind

doi:10.1006/jcat.1996.0045

Cited by 48 publications

(26 citation statements)

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“…A similar mechanism was previously proposed to explain egg-yolk Pt distributions in the preparation of Pt/Al 2 O 3 pellets. [27] The processes taking place inside an Al 2 O 3 extrudate after impregnation with CoCA-pH1 solutions are schematically depicted in Figure 4 a. A simplified model, explained in the Experimental Section, was used to estimate the distribution of citrate and [CoA C H T U N G T R E N N U N G (H 2 O) 6 ] 2 + inside Al 2 O 3 extrudates after impregnation.…”

Section: Resultsmentioning

confidence: 99%

Monitoring Transport Phenomena of Paramagnetic Metal‐Ion Complexes Inside Catalyst Bodies with Magnetic Resonance Imaging

Bergwerff

Lysova

Espinosa-Alonso

et al. 2008

Chemistry A European J

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An indirect magnetic resonance imaging (MRI) method has been developed to determine in a noninvasive manner the distribution of paramagnetic Co2+ complexes inside Co/Al2O3 catalyst extrudates after impregnation with Co2+/citrate solutions of different pH and citrate concentrations. UV/Vis/NIR microspectroscopic measurements were carried out simultaneously to obtain complementary information on the nature of the Co2+ complexes. In this way, it could be confirmed that the actual distribution of Co2+ inside the extrudates could be derived from the MRI images. By combining these space‐ and time‐resolved techniques, information was obtained on both the strength and the mode of interaction between [Co(H2O)6]2+ and different Co2+ citrate complexes with the Al2O3 support. Complexation of Co2+ by citrate was found to lead to a stronger interaction of Co with the support surface and formation of an eggshell distribution of Co2+ complexes after impregnation. By addition of free citrate and by changing the pH of the impregnation solution, it was possible to obtain the rather uncommon egg‐yolk and egg‐white distributions of Co2+ inside the extrudates after impregnation. In other words, by carefully altering the chemical composition and pH of the impregnation solution, the macrodistribution of Co2+ complexes inside catalyst extrudates could be fine‐tuned from eggshell over egg white and egg yolk to uniform.

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Section: Resultsmentioning

confidence: 99%

Monitoring Transport Phenomena of Paramagnetic Metal‐Ion Complexes Inside Catalyst Bodies with Magnetic Resonance Imaging

Bergwerff

Lysova

Espinosa-Alonso

et al. 2008

Chemistry A European J

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“…To apply this approach to a specific system, the model requires inputs of several transport and deposition parameters, such as the effective diffusion coefficient, the equilibrium adsorption constant, the intrinsic permeability and the crystallization rate coefficient. These parameters are based on the state of the support or can be obtained from separate experiments (Papageorgiou et al, 1996).…”

Section: Modelmentioning

confidence: 99%

“…Therefore, the connection between impregnation and drying is not clear, and the impact of impregnation on drying has not been fully understood. Moreover, a lot of previous work has concentrated on obtaining better agreement between the computational results and experimental data for some specific systems (Aksoylu et al, 1999;Galarraga et al, 2001;Melo et al, 1980b;Papageorgiou et al, 1996;Sceiza et al, 1986). An analysis of parametric influences on impregnation and drying of supported catalysts has not been developed systematically.…”

Section: Introductionmentioning

confidence: 97%

A parametric investigation of impregnation and drying of supported catalysts

Khinast

Glasser

2008

Chemical Engineering Science

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“…By addition of citric acid to the impregnation solution the catalyst dispersion can be controlled. [19] We found in addition, that the calcination temperature can be reduced markedly from ca. 350°C to 175°C.…”

Section: Membrane Activationmentioning

confidence: 65%

Catalytic Polymer Membranes for high Temperature Hydrogenation of viscous Liquids

Fritsch

Bengtson

2006

Adv Eng Mater

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Polymeric membranes with high oil fluxes were developed and catalytically activated by a new route of direct calcination of polymeric membranes charged by Pd or Pt catalyst precursors. High concentrations of citric acid mixed with the precursors afforded a decrease of the calcination temperature to 175°C. Membrane reactor tests in the flow through contactor mode displayed high reactivities for sunflower oil hydrogenation. Pt showed a similar activity to Pd catalysts as measured by iodine value and generated about 13% less trans‐isomers but 5% more stearic acid at an iodine value of 90. By means of alumina supported catalysts tests of methyl oleate (cis‐C18:1) and methyl elaidate (trans‐C18:1) hydrogenation exhibited a different pathway of reaction by either isomerization followed by reduction (Pd) or primarily direct reduction to methyl stearate (Pt).

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Preparation of Pt/γ-Al2O3Pellets with Internal Step-Distribution of Catalyst: Experiments and Theory

Cited by 48 publications

References 0 publications

Monitoring Transport Phenomena of Paramagnetic Metal‐Ion Complexes Inside Catalyst Bodies with Magnetic Resonance Imaging

Monitoring Transport Phenomena of Paramagnetic Metal‐Ion Complexes Inside Catalyst Bodies with Magnetic Resonance Imaging

A parametric investigation of impregnation and drying of supported catalysts

Catalytic Polymer Membranes for high Temperature Hydrogenation of viscous Liquids

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