Selectivity in sorption and hydrogenation of methyl oleate and elaidate on MFI zeolites

Selective catalytic removal of trans-monounsaturated fatty acid methyl esters: nano-sized Pt clusters embedded within Na–ZSM-5 zeolite crystals preferentially catalyze the hydrogenation of methyl elaidate ( trans isomer) from its equimolar mixture with methyl oleate ( cis isomer). [Display omitted]...

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Veröffentlicht in:Journal of catalysis Jg. 270; H. 1; S. 172 - 184
Hauptverfasser: Philippaerts, An, Paulussen, Sabine, Turner, Stuart, Lebedev, Oleg I., Van Tendeloo, Gustaaf, Poelman, Hilde, Bulut, Metin, De Clippel, Filip, Smeets, Pieter, Sels, Bert, Jacobs, Pierre
Format: Journal Article
Sprache:Englisch
Veröffentlicht: Amsterdam Elsevier Inc 22.03.2010
Elsevier
Schlagworte:
Catalysis
Chemistry
Exact sciences and technology
General and physical chemistry
Ion-exchange
Methyl elaidate
Methyl oleate
Oleochemistry
Pt clusters
Pt/ZSM-5 zeolites
Removal trans fatty acid methyl esters
Selective hydrogenation
Selective sorption
Surface physical chemistry
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
Vegetable oil conversion
Zeolites: preparations and properties
Pt/ZSM-5 zeolites
Pt clusters
Removal trans fatty acid methyl esters
Selective sorption
Selective hydrogenation
Oleochemistry
Methyl oleate
Vegetable oil conversion
Methyl elaidate
Particle size
Hydrogen
Fatty ester
Activation
Vegetable oil
X ray
Selectivity
Hydrogenation
Isomer
Chemical reduction
Tomography
Photoelectron spectrometry
Ion exchange
Low temperature
Chemisorption
Scanning electron microscopy
Catalyst selectivity
Fatty acids
Conversion
X ray diffraction
High pressure
Sorption
Heterogeneous catalysis
Impregnation
Transmission electron microscopy
Adsorption
Preparation
Distribution
Catalyst
Electrons
ISSN:0021-9517, 1090-2694
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Zusammenfassung:Selective catalytic removal of trans-monounsaturated fatty acid methyl esters: nano-sized Pt clusters embedded within Na–ZSM-5 zeolite crystals preferentially catalyze the hydrogenation of methyl elaidate ( trans isomer) from its equimolar mixture with methyl oleate ( cis isomer). [Display omitted] Different zeolites were tested for selective removal of methyl elaidate ( trans isomer) from an equimolar mixture with methyl oleate ( cis isomer). Sorption experiments of the geometric isomers show that only ZSM-5 samples with reduced Al content in the framework are able to discriminate among the bent cis and the linear trans fatty acid methyl esters. Hydrogenation experiments of equimolar methyl oleate and elaidate mixtures at low temperature (65 °C) and high hydrogen pressure (6.0 MPa), using Pt catalysts, confirm this result. Only with a Pt/Na–ZSM-5 catalyst outspoken selectivity for the hydrogenation of the trans isomer is obtained. In order to prepare a selective Pt/ZSM-5 catalyst, the influence of Pt addition (impregnation, ion-exchange and competitive ion-exchange) and Pt activation (different calcination and reduction temperatures) on the Pt-distribution and Pt particle size was investigated using SEM, bright-field and HR TEM, EDX, electron tomography, CO-chemisorption, XPS, XRD, and UV–vis measurements. The best result in terms of hydrogenation activity and selectivity is obtained with a Pt/ZSM-5 catalyst, which is prepared via competitive ion-exchange, followed by slow calcination up to 350 °C under high O 2 flow and a reduction up to 500 °C under H 2. This preparation method leads to a Pt/ZSM-5 catalyst with the best Pt distribution and the smallest Pt clusters occluded in the zeolite structure. Finally, the influence of zeolite crystal size, morphology, and elemental composition of ZSM-5 on hydrogenation activity and selectivity was investigated in detail.
ISSN:0021-9517
1090-2694
DOI:10.1016/j.jcat.2009.12.022