Iron Tetrasulfophthalocyanine Immobilized onto Amine Modified Mesostructured Cellular Foam as a Heterogeneous Catalyst in the Oxidation of Cyclohexene

Metallophthalocyanines (MPcs) is one of the most prominent catalysts that have been dominantly used in oxidation reactions. [1] The immobilization of MPcs onto porous supports has been extensively carried out by various methods to achieve stable and reusable catalysts [1]. Mesostructured cellular foam (MCF) is a type of mesoporous silica; possess uniform spherical cells and windows with ultra-large 3D pore sizes, which make it a promising candidate to be used as support for the immobilization of macrocyclic complexes such as MPcs [2]. This type of support circumvents the diffusion limitation issue of substrates, which is crucial in the liquid-phase heterogeneous catalytic reactions [3]. In this work, MCF is functionalized with amine groups (NH2-MCF) and then used as support for the immobilization of iron tetrasulfophthalocyanine (FePcS) through electrostatic interaction between charged sulfonated and amine groups in aqueous media. The absorption of FePcS on NH2-MCF and its kinetics were examined by UV-Vis spectroscopy. Moreover, the physicochemical properties of the prepared material were characterized by low angle PXRD, N2 adsorption-desorption, FESEM, FT-IR, and UV-DRS. The catalytic performance of the supported catalyst (FePcS@NH2-MCF) was investigated in the oxidation of cyclohexene using molecular oxygen and iso-butyraldehyde as sacrificial co-reductant. Under the optimized conditions, cyclohexene was oxidized into cyclohexene oxide and cyclohexenone with high conversion (92%) and selectivity (80%) towards the epoxide product. Scheme 1. A) Electrostatic immobilization of FePcS into the inner walls of amino functionalized MCF and B) Cyclohexene oxidation reaction with molecular oxygen and FePcS@NH2-MCF.

Keywords:

Mesostructured Cellular Foam , Iron Tetrasulfophthalocyanine , Immobilization , Oxidation Reaction