Simple carbonaceous-material-loaded mesoporous SiO₂ composite catalyst for epoxide-CO₂ cycloaddition reaction

Area of Science:

• Materials Science
• Catalysis
• Green Chemistry

Background:

• Developing efficient catalysts for CO2 utilization is crucial for sustainable chemical synthesis.
• Heterogeneous catalysts offer advantages in separation and reusability compared to homogeneous systems.
• Metal- and solvent-free reaction conditions are desirable for environmental and economic reasons.

Purpose of the Study:

• To synthesize and characterize a novel composite catalyst, Ar-G-CM/SiO2, for CO2 cycloaddition reactions.
• To evaluate the catalytic performance of Ar-G-CM/SiO2 under metal- and solvent-free conditions.
• To assess the reusability and stability of the synthesized catalyst.

Main Methods:

• Hydrothermal synthesis using arginine, glucose, and tetraethylorthosilicate to create the Ar-G-CM/SiO2 composite.
• Utilizing mesoporous SiO2 as a support for the carbonaceous material, providing high surface area and hydrogen bond donor groups.
• Testing the catalyst in the cycloaddition reaction of propylene oxide with CO2 under varying temperatures and pressures.

Main Results:

• The Ar-G-CM/SiO2 catalyst demonstrated high yield (62%) and selectivity (99%) for propylene carbonate synthesis from propylene oxide and CO2 at 40°C and 2 MPa.
• The catalyst exhibited good performance (>90% yield and selectivity) for sterically hindered epoxides at 120°C.
• The catalyst was successfully reused for six cycles without significant loss of activity, attributed to restrained carbon deposition by the mesoporous structure.

Conclusions:

• The synthesized Ar-G-CM/SiO2 composite catalyst is highly effective for CO2 cycloaddition reactions.
• The catalyst operates efficiently under mild, metal-absent, and solvent-free conditions, aligning with green chemistry principles.
• The catalyst's reusability and structural stability make it a promising candidate for industrial applications in CO2 utilization.