Porphyrin-kaolinite as efficient catalyst for oxidation reactions

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Biomimetic catalysts offer sustainable alternatives for chemical synthesis.
• Iron porphyrins are versatile catalysts for oxidation reactions.
• Kaolinite clay provides a robust and accessible support material.

Purpose of the Study:

• To prepare and characterize a novel biomimetic catalyst using functionalized kaolinite clay and iron porphyrin.
• To evaluate the catalytic activity of the new material in various oxidation reactions.
• To explore the potential of this catalyst for selective organic transformations.

Main Methods:

• Functionalization of kaolinite clay with amino groups via DMSO and ethanolamine.
• Immobilization of [meso-tetrakis(pentafluorophenyl)porphinato]iron(III) (Fe(TPFPP)) onto the modified clay.
• Characterization using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and UV-vis spectroscopy.
• Catalytic testing in cyclooctene epoxidation, cyclohexane ketonization, and cyclohexanone Baeyer-Villiger oxidation.

Main Results:

• A layered material with a basal spacing of 10.73 Å was successfully synthesized.
• FTIR confirmed the presence of secondary amine groups, indicating successful clay functionalization.
• UV-vis spectroscopy showed a red shift in the Soret band, suggesting Fe(III)P to Fe(II)P reduction.
• The catalyst achieved 100% epoxide yield in cyclooctene epoxidation.
• Cyclohexane ketonization yielded cyclohexanone as the major product.
• Baeyer-Villiger oxidation of cyclohexanone resulted in 85% conversion to ε-caprolactone with total selectivity.

Conclusions:

• The functionalized kaolinite clay serves as an effective support for iron porphyrin catalysts.
• The novel biomimetic catalyst demonstrates high efficiency and selectivity in oxidation reactions.
• This material presents a promising platform for green chemistry applications in selective oxidation processes.