The observation of equilibria present in stepwise gas phase hydrogenation reactions
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- 作者：Andrew McFarlane ; Liam McMillan ; Ian Silverwood ; Neil G. Hamilton ; David Siegel ; Stewart F. Parker ; David T. Lundie ; David Lennon
- 关键词：Pentene hydrogenation ; Pentadiene hydrogenation ; Infrared spectroscopy ; Palladium/alumina catalyst
- 刊名：Catalysis Today
- 出版年：2010
- 出版时间：15 October 2010
- 年：2010
- 卷：155
- 期：3-4
- 页码：206-213
- 全文大小：295 K
文摘
The hydrogenation of a number of C5 olefins (pent-1-ene, trans-pent-2-ene, cis-pent-2-ene, trans-1,3-pentadiene and a technical mixture of 1,3-pentadiene) over a 1 % Pd/Al2O3 catalyst has been studied using in situ infrared spectroscopic methods to observe the changes in the gas phase molecules during the course of the reaction. Whereas trans-pent-2-ene is directly hydrogenated to pentane, the reaction profile for cis-pent-2-ene indicates a consecutive process involving the formation of gaseous trans-pent-2-ene as a reaction intermediate. Extending these studies to trans-1,3-pentadiene shows the terminal double bond to be hydrogenated first to produce trans-pent-2-ene in the gas phase, which is then subsequently hydrogenated to the alkane. A reaction scheme is proposed that defines how the molecules are partitioned between the gaseous and adsorbed phases. This scheme makes use of a previously postulated two-site adsorption model. Analysis of a technical grade of 1,3-pentadiene indicates the trans-monoene to play a significant role in the stepwise hydrogenation process.