Selective epoxidation of olefins over Co(II)-Schiff base immobilised on KIT-6

Authors:  P. Visuvamithiran, M. Palanichamy, K. Shanthi, V. Murugesan

Abstract:
Co-Salen complex immobilised on amine functionalised mesoporous KIT-6 (Co-S-KIT-6) was prepared by post synthetic method. The synthesised materials were characterized by techniques such as small angle XRD, FT-IR, DRSUV–vis, thermal analysis, N2 sorption, ESR, SEM and TEM. The small angle XRD patterns, N₂ sorption studies and TEM images clearly revealed immoblisation of Co-Salen complex inside the pores of KIT-6. Further, decrease in the surface area, pore volume and pore diameter compared to parent KIT-6 also confirmed the immobilisation of Co-Salen complex inside the mesopores. The catalytic activity of Co-S-KIT-6 was tested in the liquid phase epoxidation of olefins using H₂O₂ as the oxidant. The influence of reaction parameters such as catalyst amount, reaction temperature, solvent and reaction time on the catalytic activity of Co-S-KIT-6 was also studied. The solvent polarity played a key role in the conversion and selectivity. Polar aprotic solvent such as acetonitrile exhibited high conversion with high selectivity of the product. Further, it was demonstrated that Co-S-KIT-6 can be recycled upto five cycles without loss of its catalytic activity. In addition, the catalyst was found to be highly active, stable and selective.

Keywords:
KIT-6
Co-Schiff base
Solvent polarity
Epoxidation
Olefins
H₂O₂

Published in: Applied catalysis A: General  (Volumes 462–463, Pages 1-310, 10 July 2013)

Publisher: Elsevier      

ISSN Information: 0926-860X

Selective epoxidation of olefins over Co(II)-Schiff base immobilised on KIT-6

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