Hydrocarbons from synthesis gas: selectivity changes induced by the zeolite matrix on the metallic function in Rh/Y catalysts
✍ Scribed by G.J. Siri; A. Guerrero-Ruiz; I. Rodriguez-Ramos; P. Terreros; J.L.G. Fierro
- Book ID
- 103963397
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 816 KB
- Volume
- 107
- Category
- Article
- ISSN
- 0926-860X
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✦ Synopsis
RhNaY and RhHY zeollites have been prepared either by ion exchange with RhCls or by Rhe (CO 112 sublimation under vacuum. Except in the latter case, very small rhodium aggregates were obtained within the supercages of faujasitic zeolite. Photoelectron spectra and IR of chemisorbed carbon monoxide revealed that the interaction of these clusters with the zeolite matrix differs substantially, depending on the acidity of the zeolite. These clusters become aggregated during reduction or on-stream mainly at the outer zeolite surface irrespective of the degree of protonation of the zeolite. The RhNaY' catalyst proved to be interesting for the conversion of CO/H, mixtures to low carbon number alkenes and alkanes with a propensity to form butenes/butanes. However, the parent RhHY' homologue produced a higher proportion of saturated and branched hydrocarbons, mainly the C, fraction. These important differences in product distribution in the RhHY' zeolite have been associated with the presence of cationic rhodium species as revealed by X-ray photoelectron spectroscopy and carbon monoxide chemisorption.