Perspectives on catalyst development

Due in large part to the development of ruthenium catalysts, olefin metathesis reactions can now be carried out on a diverse array of functionalized electron-rich and electron-poor olefins. As we have described, mechanistic analysis was instrumental in the design of more highly active second generation catalysts with expanded substrate scope, which was achieved by proper differentiation of the two L-type ligands within the (L)2(X)2Ru=CHR framework. Further investigations have revealed that these new catalysts display several unexpected features, and mechanistic analysis continues to be an invaluable tool for understanding reactivity patterns and for the development of new catalyst systems. 

The biggest challenge that remains in the field is control over the stereoselective formation of cis or trans olefins. Further experimental and theoretical mechanistic studies are needed to identify the stereodetermining steps of the reaction, and to discern the structures of important intermediates, such as the olefin complex B and 

Transition Metal-Carbene Complexes in Olefin Metathesis 

This model is generally presented in inorganic textbooks. For a particularly good discussion, see Spessard, G.O., Miessler, G.L., Organometallic Chemistry, Prentice-Hall, Englewood Cliffs, NJ, 1997, chapter 10. 

Metal-Ligand Multiple Bonds, Wiley, New York, 1988, pp. 11-14, 304—307. Churchill, M.R., Youngs, W.J., Inorg. Chem., 1979, 18, 2454-2458. 

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The chapters in Characterization and Catalyst Development An Interactive Approach, assembled from both academic and industrial contributors, give a unique perspective on catalyst development Some chapters thoroughly characterize the catalyst prior to plant evaluation, whereas others utilize characterization to explain performance variances. Some new types of catalysts incorporated into this volume include the preparation of novel catalyst supports based on alumina and hydrous titanates. Attrition-resistant catalysts and ultrafine ceramics were prepared by modified spray-drying methods. New catalyst compositions based on vanadium-containing anionic clays were proposed for oxidation. A recently commercialized catalyst based on magnesium spinel was proposed for use in the abatement of sulfur oxide pollutants in fluid... 

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