Preparation, characterization and investigation of the catalytic activity of a silica-based heterogeneous catalyst functionalized with cobalt(II) phthalocyanine in benzyl alcohol oxidation

In this thesis, a heterogeneous catalyst was developed for the selective oxidation of benzylic alcohols to aldehydes. For this purpose, C2-symmetric diol substituted cobalt(II) phthalocyanine was covalently bonded to the mesoporous MCM-41 silica surface to synthesize MCM-41-CoPc-Ph(p) catalyst. The structure and surface properties of the catalyst were characterized in detail by FT-IR, XRD, UV-Vis, SEM-EDS, TEM, TGA and N₂ adsorption-desorption analyses. In order to evaluate the catalytic performance, the oxidation of benzyl alcohol was selected as a model reaction and the effects of parameters such as temperature, solvent, oxidant type, reaction time, substrate and oxidant ratios on conversion and selectivity were investigated. In the best conditions, the catalyst showed conversion rates up to 82.8% with 100% benzaldehyde selectivity. In experiments with various benzylic alcohol derivatives, the catalyst exhibited high efficiency and selectivity over a wide range of substrates. The reusability of the catalyst was investigated and it was found that it maintained its high activity without structural or morphological deterioration for at least three cycles. The results obtained in this study indicate that the MCM-41-CoPc-Ph(p) catalyst is an effective and sustainable alternative catalyst for benzylic alcohol oxidation. The developed catalyst has significant potential in industrial and academic terms by providing a reusable, environmentally friendly and highly selective system in accordance with the principles of green chemistry.