Hydrogenation

Advances reported in the period of 1996–2021 in the field of heterogeneous catalytic hydrogenations have been reviewed. Due to their usefulness and importance these methods remain in the forefront of research in overlapping areas such as synthetic, process, industrial, medicinal, and green chemistry. Hydrogenation on solid catalysts is a fundamental tool in developing environmentally benign processes and contributes to the sustainable synthetic endeavor. In this chapter the hydrogenation of functional groups is discussed first including all major substrates, such as CC multiple bonds, CO bonds, CN multiple bonds. Then the special cases of chemo- and regioselective hydrogenations are described followed by the complete hydrogenation of substrates possessing multiple hydrogenation sensitive groups. Finally, emerging areas of microwave and ultrasound-assisted hydrogenations conclude the work. The important area of enantioselective heterogeneous catalytic hydrogenation is only mentioned here, and is covered in detail in a separate chapter under Asymmetric synthesis by solid catalysts.