Compressed carbon dioxide as a medium in catalytic hydrogenations: Engineering and chemistry

In the frame of designing eco-friendly chemical processes, solvents represent a crucial economic and environ-mental concern. Compressed carbon dioxide (CO2) is an alternative green solvent for many industrial applica-tions. Herein, we present the most relevant aspects of using compressed CO2 in metal-catalyzed hydrogenation reactions. In the first part, we discuss engineering fundamentals for the description of processes in supercritical fluids, gas-expanded liquids, continuous-flow applications and process design, including safety aspects and ex-amples of heterogeneous catalysis. In the second part, we focus on catalytic systems based on both metal complexes and nano-systems, emphasizing how the catalysts have been adapted to the specificity of CO2. For this purpose, significant aspects such as the catalyst design, the reaction conditions and the use of co-solvents are considered. The main goal of this review is to show the advantages of using this green solvent in catalytic hy-drogenations, including a critical analysis concerning its limitations.

Automated summary

This article discusses the importance and advantages of using compressed carbon dioxide (CO2) as a green solvent in designing eco-friendly chemical processes. It covers engineering fundamentals, catalyst design, and reaction conditions, emphasizing the specificity of CO2.