Hydrogenation is a key reaction in chemistry, from the hydrorefining of heavy oil and the production of petrochemicals, to the preparation of deuterium and tritium labelled compounds for the pharmaceutical industry. The scale of these reactions varies from thousands of tonnes of product down to a few milligrams, and this area of catalysis has a value of over £544M. In many ways hydrogenation, even selective hydrogenation, is seen as a mature area of catalysis. However even today we find ourselves unable to specify, design, and construct hydrogenation catalysts to order. For some systems this has not been, and is not, a problem. The catalysts developed are both highly selective and active. However as the need for more complex hydrogenations increases, e.g. selective hydrogenation of a specified functional group in the presence of other reactive functional groups, our inability to produce the desired catalyst due to a lack of fundamental understanding, is revealed. Even in such a widely researched area many of the mechanisms are still unknown or poorly understood. Our interest here lies in using isotopically labelled species (2H, 13C, 14C, 15N 18O) to determine the reaction mechanism and hence to understand the fundamental aspects of the hydrogenation process. Some recent publications in the area are reported below.
Supported Metal Catalysts; Preparation, Characterisation and Function. Part V. Activities and Selectivities of Platinum Catalysts in the Reactions of Cyclopropane, Ethene, 1,3-Butadiene, and 2-Butyne with Dihydrogen. J. Catal., 162, 10 - 20 (1996). (with G.Webb, P.B.Wells, R.Whyman, G.D.McLellan, D.A.Whan, S.Mather, S. Simpson, L.Conyers, and M.B.T.Keegan).
Cycloalkene Hydrogenation over Palladium Catalysts. Applied Catal.A, 187, 161 - 168 (1999). (with G.J.Kelly, S.R.Watson, and R.Gulickx).
Effect of Toluene-d8 on the Hydrogenation of 1,3-Hexadiene over a Palladium/silica Catalyst - Promoter and Poison. Langmuir, 16, 6519 - 6526 (2000). (with D.Lennon, S.Munro and P.Colman)
Control of Activity and Selectivity in Alkyne Hydrogenation: Effect of Competitive Reactions. Appl. Catalysis A, 237, 201 - 209 (2002). (C.A. Hamilton, G.J. Kelly, R.R. Spence, and D. de Bruin)
Para-substituted Aniline Hydrogenation over Rhodium Catalysts: Metal Crystallite Size and Catalyst Pore Size Effects. "Catalysis of Organic Reactions", (John Sowa Jr, ed.), Marcel Dekker, New York, (2005). (with K.J. Hindle and G. Webb).
C-5 Alkene Hydrogenation: Effect of Competitive Reactions on Activity and Selectivity. Catalysis Today, 116, 22 – 29, (2006). (with A.S. Canning, A. Monaghan, and T. Wright)
We also collaborate with Prof. Ha-Jo Freund freund@FHI-Berlin.mpg.de and Prof. Robert Schlögl acsek@fhi-berlin.mpg.de at the Fritz-Haber-Institut in Berlin www.fhi-berlin.mpg.de/cp/cp.html on examining the fundamentals of the active site for selective hydrogenation.
Through this collaboration we have been able, for the first time, define the site and hydrogen requirements for selective hydrogenation of alkynes.
Structure-Reactivity Relationships on Supported Metal Model Catalysts: Adsorption and Reaction of Ethene and Hydrogen on Pd/Al2O3/NiAl(110). J.Catal., 200, 330 - 339, (2001). (with Sh. Shaikhutdinov, M. Heemeier, M. Bäumer, T. Lear, D. Lennon, R.J. Oldman, and H.-J. Freund)
Hydrogenation on Metal Surfaces: Why are Nanoparticles more Active than Single Crystals ? Angewandte Chemie, 42, 5240 - 5243 (2003). (with A.M. Doyle, Sh.K. Shaikhutdinov, and H.-J. Freund)
Alkyne Hydrogenation over Pd Catalysts: A New Paradigm. J. Catal., 242, 26 - 37, (2006). (with D. Teschner; E.Vass; M. Hävecker; S. Zafeiratos; P. Schnörch; H. Sauer; A. Knop-Gericke; M. Chamam; A. Wootsch; A.S. Canning; J.J. Gamman; J. McGregor; L.F. Gladden; R. Schlögl)