Shape-Selective Zeolites for Tandem CO₂ Hydrogenation-Carbonylation Reactions

Area of Science:

• Chemical Engineering
• Catalysis
• Green Chemistry

Background:

• Carbon dioxide (CO2) valorization is key for carbon-circular chemistry.
• The reverse water-gas shift (RWGS) reaction, crucial for CO2 activation, is equilibrium-limited at moderate temperatures.
• Integrating RWGS with subsequent carbonylation reactions is challenging due to reaction incompatibilities.

Purpose of the Study:

• To develop a one-pot strategy that reconciles CO2 activation (RWGS) and carbonylation reactions.
• To overcome the equilibrium limitations of RWGS at moderate temperatures.
• To enable the synthesis of bulk and fine chemicals using CO2 as a C1 building block.

Main Methods:

• A compartmentalized approach using a zeolite framework (LTA) encapsulating platinum (Pt) nanoparticles.
• Selective generation of carbon monoxide (CO) via RWGS under mild conditions within the zeolite.
• Continuous consumption of CO in a one-pot carbonylation reaction, shifting the equilibrium.
• Utilizing the zeolite's molecular sieving effect to prevent undesired side reactions, such as olefin hydrogenation.

Main Results:

• Successful one-pot integration of RWGS and carbonylation reactions using CO2 and H2.
• Pt encapsulated in LTA zeolite selectively produced CO under mild conditions.
• Demonstrated Rh-catalyzed olefin hydroformylation with CO2/H2, yielding aldehydes with high yields and regioselectivities.
• Extended the methodology to various carbonylations for synthesizing bulk and fine chemicals.

Conclusions:

• Zeolite encapsulation provides a viable strategy to overcome incompatibilities between RWGS and carbonylation reactions.
• This approach effectively utilizes CO2 as a C1 feedstock for chemical synthesis.
• The developed methodology offers a promising pathway towards sustainable chemical production and carbon circularity.