Conversion of Syngas into Formic Acid

Reaction and separation system for CO2 hydrogenation to formic acid catalyzed by iridium immobilized on solid phosphines under base-free condition

Hydrogenation of carbon dioxide (CO₂) to produce formic acid (HCOOH) in base-free condition can avoid waste producing and simplify product separation process. However, it remains a big challenge because of the unfavorable energy in both thermodynamics and dynamics. Herein, we report the selective and efficient hydrogenation of CO₂ to HCOOH under neutral conditions with imidazolium chloride ionic liquid as the solvent, catalyzed by a heterogeneous Ir/PPh₃ compound. The heterogeneous catalyst is more effective than the homogeneous one because it is inert in catalyzing the decomposition of product. A turnover number (TON) of 12700 can be achieved, and HCOOH with a purity of 99.5% can be isolated by distillation because of the non-volatility of the solvent. Both the catalyst and imidazolium chloride can be recycled at least 5 times with stable reactivity.

Challenges in the Greener Production of Formates/Formic Acid, Methanol, and DME by Heterogeneously Catalyzed CO2 Hydrogenation Processes

The recent advances in the development of heterogeneous catalysts and processes for the direct hydrogenation of CO₂ to formate/formic acid, methanol, and dimethyl ether are thoroughly reviewed, with special emphasis on thermodynamics and catalyst design considerations. After introducing the main motivation for the development of such processes, we first summarize the most important aspects of CO₂ capture and green routes to produce H₂. Once the scene in terms of feedstocks is introduced, we carefully summarize the state of the art in the development of heterogeneous catalysts for these important hydrogenation reactions. Finally, in an attempt to give an order of magnitude regarding CO₂ valorization, we critically assess economical aspects of the production of methanol and DME and outline future research and development directions.

Recent developments in the catalytic hydrogenation of CO2 to formic acid/formate using heterogeneous catalysts

This review highlights the recent trends in the heterogeneous hydrogenation of CO₂ to formic acid/formate.

Hydrogen energy future with formic acid: a renewable chemical hydrogen storage system

Formic acid, the simplest carboxylic acid, could serve as one of the better fuels for portable devices, vehicles and other energy-related applications in the future.