Influence of the Addition of a Second Metal on the Catalytic Performance of Pt-Beta Agglomerated Catalyst in the Hydrois
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Influence of the Addition of a Second Metal on the Catalytic Performance of Pt-Beta Agglomerated Catalyst in the Hydroisomerization of n-Octane Marı´a Jesu´s Ramos Æ Vicente Jime´nez Æ Antonia Fu´nez Æ Amaya Romero Æ Paula Sa´nchez Æ Jose´ Luis Valverde
Received: 17 December 2007 / Accepted: 7 July 2008 / Published online: 23 July 2008 Ó Springer Science+Business Media, LLC 2008
Abstract In this work, the hydroisomerization of n-octane on mono and bimetallic beta agglomerated zeolite based catalysts was investigated. As the metal function, platinum and combinations with nickel and tin were studied. Test reactions were carried out at 10 bar and 290– 410 °C. The bimetallic catalyst with the lowest amount of Ni yielded the greatest multibranched selectivity. Keywords
Zeolite Binder Bimetallic
1 Introduction The current environmental requirements are giving rise to a general reduction in both Reid vapour pressure and aromatics, alkenes, sulphur and Methyl tert-butyl ether (MTBE) contents, which will have a negative impact on the octane number of the gasoline pool [1]. Isomerization of long-chain n-alkanes appears to be an interesting alternative since provides branched molecules which possess higher octane number than linear ones. Isomerization of alkanes is carried out over bifunctional catalysts consisting of an acid function, provided by solid acids; i.e., zeolites, and a metallic function (noble metals). Isomerization takes place in the acid sites of the bifunctional catalyst whereas the metal provides hydrogenationdehydrogenation capability. Both acid and metal site
M. J. Ramos (&) V. Jime´nez A. Fu´nez A. Romero P. Sa´nchez J. L. Valverde Departamento de Ingenierı´a Quı´mica, Facultad de Ciencias Quı´micas, Universidad de Castilla-La Mancha, Avd. Camilo Jose´ Cela s/n, 13071 Ciudad Real, Spain e-mail: [email protected]
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density are important and their proper balance is critical in determining the activity of the catalyst [2]. As the hydrogenating-dehydrogenating function, several metals have been tested including Pt, Pd, Rh, Ir, Ru, Re and Ni [3]. In an extensive study, Guisnet [4] reported the benefits that platinum produces in zeolites. With high values of the metal/acid balance, the platinum acid zeolites are very stable, because the metal avoids deactivation by coke. Additionally, it has been proved that catalytic performance of a metal catalyst may be improved by the addition of a second metal. Geetha Bhavani et al. [5] reported the formation of bimetallic Ni–Pt particles on zeolites beta and mordenite. The best metal–acid balance between bimetallic particles and acid sites of the support allowed an enhanced activity, isomerization selectivity and sustainability of the catalysts for ethylbenzene hydroisomerization. Jorda˜o et al. [6] observed how the catalytic activity and stability of the Ni/ HUSY catalyst were much lower than the monometallic Pt/ USY. The presence of small platinum amounts in the bimetallic catalysts improved both properties and produced more active catalysts i
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