Catalytic Upgrading of Bio-Based Ketonic Acids to Pyrrolidones with Hydrogen Donor Sources

Comprehensive utilization of biomass resources is necessary for the sustainable production of value-added chemicals and biofuels. For hydrogenative conversion processes, the type of hydrogen donor source among the many catalytic parameters plays an important role in upgrading of bio-based ketonic acids (mainly including biomass-derived levulinic acid (LA) and its derivatives) to pyrrolidones. In this chapter, one-pot processes for the reductive amination of bio-based ketonic acids and their advantages are introduced based on the classification of hydrogen donor sources, and the involved mechanisms and reaction parameters (e.g., reaction time, temperature, pressure, and reactor type) are discussed. The functional requirements of the catalyst are highlighted, and the effect of catalyst composition and properties on its activity and reaction path is described in detail. An outlook on the development of promising reduction systems for biomass conversion is given.