Pd-loaded modulated MOF-808: a bifunctional solid-acid catalyst for one-pot oxidation-acetalization

Area of Science:

• Catalysis
• Materials Science
• Green Chemistry

Background:

• Growing demand for fine chemicals necessitates efficient and sustainable catalytic processes.
• Designing multifunctional solid catalysts for tandem reactions remains a significant challenge.
• Catalytic cascade reactions offer operational efficiency and high atom economy.

Purpose of the Study:

• To rationally design a bifunctional palladium/MOF-808 catalyst for one-pot tandem oxidation-acetalization.
• To tailor the acidic properties of MOF-808 through defect engineering for enhanced catalytic performance.
• To investigate the synergy between metallic and acidic sites in the bifunctional catalyst.

Main Methods:

• Synthesis of MOF-808 variants using different modulating agents for defect engineering.
• Structural characterization (XPS, TEM) to confirm MOF structure and Pd nanoparticle dispersion.
• Immobilization of palladium nanoparticles via double-solvent impregnation.
• Testing the bifunctional catalyst for benzyl alcohol oxidation and acetalization.

Main Results:

• Engineered MOF-808-H2O/HAc/HCl exhibited enhanced acidity while preserving the microporous framework.
• Optimal Pd/MOF-808-H2O/HAc/HCl achieved 99.9% benzyl alcohol conversion and 82.8% acetal selectivity.
• The catalyst outperformed traditional zeolite-supported Pd catalysts and demonstrated excellent stability over six cycles without leaching.

Conclusions:

• Rational design of bifunctional Pd/MOF-808 catalysts enables efficient tandem catalysis.
• Tailored moderate acidity of the MOF-808 support is crucial for directing selectivity in acetalization.
• The catalyst exhibits high stability and recyclability, highlighting its potential for sustainable fine chemical synthesis.