Introducing a Second Liquid Phase in the Carbon Dioxide Hydrogenation to Formic Acid: Impact on Catalytic Conversion in Ru-Catalyzed Systems

High Resolution Image Download MS PowerPoint Slide The synthesis of formic acid (FA) from CO 2 and hydrogen is a renewable pathway as an alternative to fossil-based indirect carbonylation of water and offers the possibility of reducing the carbon footprint of the chemical industry. However, scaling up homogeneously catalyzed CO 2 -based FA production requires effective catalyst separation, necessitating advanced methodologies to address the challenges specific to homogeneous catalysis. Liquid/liquid multiphase catalysis is a promising solution, but its complete impact remains elusive. In this study, the influence of a second liquid phase on catalytic conversion was explored using a specially designed miniplant in combination with a model reaction system. A cis -[Ru(1,1-bis(diphenylphosphino)methane) 2 Cl 2 ] catalyst, methyl isobutyl carbinol solvent, and triethylamine as a thermodynamically compensating agent were employed. The investigation of factors influencing FA conversion in a monophasic system was conducted by varying parameters, such as temperature, pressure, gas substrate ratios, and liquid phase composition. Based on this, a study of the main variables of the biphasic system formed by introducing an aqueous phase was carried out. It was found that the introduction of water as a second phase mitigated the catalytic inhibition of FA formation observed in the monophasic system, suggesting a role in restoring the activity of the catalyst species. Therefore, for this reaction, the advantages of the separation process in biphasic reactions using water are further clarified.