4. Conclusions

This chapter reviewed the use of various catalysts including metal complexes, supported metals and metal nanoparticles, colloidal nanoparticles for selective hydrogenation of polyunsaturated olefins, mostly dienes and trienes. Selective hydrogenation of polyenes has been considered as an important process in many chemical and pharmaceutical industries. By controlling chemical environments around active catalytic sites using organic ligands, inorganic dopants, ionic liquids, dendrimers, secondary metals, etc., the catalytic activity and selectivity of various catalysts for partial hydrogenation of polyenes could be improved. Especially, nanocatalyzed selective hydrogenation represents a rapidly growing field, but there is still much work to be done to generate industrially viable nanocatalysts that can be operated under many catalytic cycles with acceptable integrity. In addition, more in-depth understanding of critical structure–function relationships should be obtained for the development of optimized nanocatalysts with high chemoselectivity and stereoselectivity.
