Selective Mono-Hydrogenation of Polyunsaturated Hydrocarbons: Traditional and Nanoscale Catalysis

Selective hydrogenation of olefins is an important process in both chemical and pharmaceutical industries. This chapter reviews intriguing catalytic studies accomplished by employing a variety of catalysts such as metal complexes, supported materials, supported metal complexes, and nanosized materials for polyene hydrogenation. In addition, new research area involving unsupported colloidal nanoparticle catalysts, which exhibit an excellent activity and selectivity toward the polyene hydrogenation is introduced. The high activity of colloidal metal nanoparticle catalysts often allows the reactions to be completed under mild conditions, at atmospheric pressure, and room temperature. These colloidal nanoparticle catalysts also offer an advantage of facile separation and multiple recycling without significant losses in activity and selectivity. This chapter provides important fundamental understandings on the influence of chemical environments (solvents, ligands, dop-ants, etc.) and compositions (metal complex, metals, alloys, etc.) toward the catalytic activity and selectivity of various catalysts in homogeneous, heterogeneous, and semi-heterogeneous conditions. The systematic evaluation discussed in this chapter would pave a way to further develop chemo-, regio-, and stereo-selective catalysts for polyene hydrogenation.