Abstract
In recent years, much interest has been shown to hybrid materials based on clays. These materials are produced by different reactions and can give a rise to intercalation compounds with different applications, depending on the type of interaction between inorganic matrix and the intercalated species. Some molecules such as dyes, pharmaceuticals, polymers and complexes have been incorporated into inorganic matrices for applications in areas such as catalysis, luminescence, drug delivery systems, adsorption and photocatalysis. In particular, transition metal complexes have recognized technological importance for application as catalysts to of hydrocarbon oxidations. However, the complexes in homogeneous medium due to their nature have low yields and selectivity. Thus, an alternative for applications requiring high temperature during the process, high conversion and selectivity is based on the use of complex immobilized into inorganic matrices. In these, use is made of "heterogeneity", the process of immobilization the homogeneous complexes (with high catalytic activity) in inorganic matrices such as kaolinite, able to modify the kinetics and mechanism of oxidation reactions. Nevertheless, the application of complex in heterogeneous medium is even further limited by the low diffusion of substrates and products in these solid matrices. Factors such as heat resistance, mechanical and chemical stability of these can lead to obtain a range of applications much more flexible. For this purpose, hybrid materials have been explored and among them stands out the kaolinite-based materials due to high thermal stability of hybrids obtained. In this project, we proposes the use such a host matrix for the immobilization of complexes of transition metals (Co 2+, Mn 2+ and Ni 2+), and the guest ligand pyridine 2,6-dicarboxylic acid (dipicolinic acid). Two strategies will be used for the incorporation of the complexes in the interlayer spaces of the matrix: i) functionalization of the matrix with the pyridine dicarboxylic ligand followed by complexation with transition metals, ii) exfoliation of the matrix functionalized in ultrasonic bath in water medium followed by complexation with transition metals. Hybrids will be characterized structural and morfologically and through various spectroscopic techniques (electronic and nuclear magnetic resonance). These solids will be applied as catalysts in hydrocarbon oxidation reactions: cis-cyclooctene (evaluation activity), and cyclohexane (selectivity) but also to reaction of Baeyer-Villiger oxidation of cyclohexanone to µ-caprolactone.
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