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

## TL;DR

This review discusses recent progress in producing propylene oxide using hydrogen and oxygen, focusing on catalyst development and reactor design to improve efficiency and safety.

## Contribution

The paper provides a comprehensive review of HOPO advancements across multiple scales, emphasizing catalyst and reactor innovations.

## Key findings

- Bimetallic nanoparticles and optimized support materials enhance catalyst stability and selectivity.
- Reactor engineering strategies improve process safety by managing reactant concentrations.
- Nanoscale and mesoscale studies offer insights for scaling up propylene epoxidation.

## Abstract

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.

This review highlights advancements in HOPO across nanoscale, mesoscale, and macroscale. It explores key aspects such as nanoparticle design, support materials, catalyst preparation methodologies, and reactor engineering. Additionally, the review highlights the impact of bimetallic nanoparticles, reaction mechanisms, and process optimizations that have contributed to improving catalyst stability, selectivity, and overall efficiency.