Paradigm Shift in Mechanistic Understanding and Catalyst Design for Heterogeneous Ethylene Methoxycarbonylation

Area of Science:

• Heterogeneous catalysis
• Organometallic chemistry
• Materials science

Background:

• Homogeneous catalysis principles are often applied to heterogeneous systems, but differences in electronic environments can cause reactivity divergence.
• Transferring homogeneous paradigms to electron-deficient supported metal centers may lead to suboptimal catalyst design.

Purpose of the Study:

• To report a reversed strategy using an oxide-supported, electron-deficient ruthenium center for ethylene methoxycarbonylation.
• To replace conventional organometallic complexes in this reaction.

Main Methods:

• Utilized an oxide-supported, electron-deficient ruthenium (Ru) center.
• Incorporated a built-in moderately basic site to facilitate a distinct proton transfer pathway.
• Evaluated catalyst activity and stability for ethylene methoxycarbonylation.

Main Results:

• The RuO_x/TiO₂ catalyst exhibited over 80 times higher activity than Ru nanocatalysts.
• Achieved 6 times higher activity compared to platinum (Pt) single-atom catalysts.
• Demonstrated exceptional stability over 180 hours with a turnover number exceeding 200,000, surpassing existing heterogeneous catalysts.

Conclusions:

• The developed catalyst offers a novel approach by reversing homogeneous catalysis paradigms.
• The electron-deficient Ru center and integrated basic site enable efficient ethylene methoxycarbonylation without strong external acids.
• This catalyst system presents a highly active, stable, and promising alternative to conventional methods.