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ERIC Number: EJ1014525
Record Type: Journal
Publication Date: 2013-May
Pages: 7
Abstractor: As Provided
Reference Count: 31
ISBN: N/A
ISSN: ISSN-0021-9584
Heterogeneous Catalysis: The Horiuti-Polanyi Mechanism and Alkene Hydrogenation
Mattson, Bruce; Foster, Wendy; Greimann, Jaclyn; Hoette, Trisha; Le, Nhu; Mirich, Anne; Wankum, Shanna; Cabri, Ann; Reichenbacher, Claire; Schwanke, Erika
Journal of Chemical Education, v90 n5 p613-619 May 2013
The hydrogenation of alkenes by heterogeneous catalysts has been studied for 80 years. The foundational mechanism was proposed by Horiuti and Polanyi in 1934 and consists of three steps: (i) alkene adsorption on the surface of the hydrogenated metal catalyst, (ii) hydrogen migration to the beta-carbon of the alkene with formation of a delta-bond between the metal and alpha-C, and finally (iii) reductive elimination of the free alkane. Hundreds of papers have appeared on the topic, along with a number of variations on the Horiuti-Polanyi mechanism. The second step is highly reversible, leading to extensive deuterium-hydrogen exchange when D[subscript 2](g) is used. This paper describes the investigation of gas-phase reactions between deuterium and 1-butene using a supported palladium catalyst under ambient laboratory conditions and how the results are consistent with the Horiuti-Polanyi mechanism. An Excel spreadsheet for modeling the extent and distribution of deuteration within butane-d[subscript x] is described. Interested readers could develop a laboratory or research experience based on results presented here. The results are also suitable for inclusion in an upper-division chemistry course in which organometallic chemistry or reaction mechanisms involving heterogeneous catalysts are discussed. The catalyst tubes are inexpensive and easy to construct. Analysis of the butane produced by [superscript1]H NMR and GC-MS leads to numerous conclusions in support of the Horiuti-Polanyi mechanism. (Contains 9 figures.)
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A