Advances in the Hydroperoxidation of Propylene to Propylene Oxide (HOPO): from Nanoscale to Mesoscale and Macroscale

Hydroperoxidation of propylene to propylene oxide (HOPO) using H₂ and O₂ offers several advantages over commercial methods such as the chlorohydrin process and the hydroperoxide process. This review presents a comprehensive exploration of the advancements in the HOPO, with a focus on catalyst development and reactor engineering. Various catalyst synthesis strategies, including the modulation of gold nanoparticle (AuNP) size, role, and types of support, and the potential of bimetallic nanoparticles are discussed. The catalytic properties of nickel and the reaction mechanism involved in the epoxidation are also presented. These strategies offer promising pathways to enhance catalyst stability, selectivity, and overall performance. Additionally, this article highlights the critical role of reactor engineering, showcasing the significance of different reactor configurations and feed concentrations enabling higher reactant concentrations that avert explosions. The review identifies key challenges and opportunities across different scales-nanoscale, mesoscale, and macroscale - with the aim to provide valuable insights and guidance for future advancements in the field of propylene epoxidation.