Study On Catalytic Performance Of Metal Tetrakis(p-Sulphophenyl)Porphyrins Supported On Chitosan By Salt Linkage

Metalloporphyrins acted as efficiently biomimetic catalysts, have been widely used for various hydrocarbon oxidation. Metalloporphyrins display a good performance in the process of oxidation. Homogeneous oxidation of ethylbenzene over metalloporphyrin with O2can produce acetophenone and phenethanol in good yields, which are an important industrial raw materials. However, the metalloporphyrins are easily exhausted one-off by oxidants and can not be recycled for next catalytic oxidation. Therefore, a hot topic, at present, is focused on seeking a robust support of metalloporphyrins for preparing a efficiently heterogeneous catalyst material, which would be employed for oxidation of ethylbenzene to the corresponding ketone and alcohol. Based on the above idea, metal tetrakis(p-sulphophenyl)metalloporphyrins were immobilized on chitosan by salt linkage as a biomimetic catalyst for oxygen oxidation of ethylbenzene in heterogenous system, which was free of any solvents and additives.The contents of this thesis are as follows:1. It is briefly reviewed that the synthesis or preparation development of porphyrins, metalloporphyrins and the immobilized metalloporphyrins, as well as the latest advancement of research on catalytic oxidation of ethylbenzene, via investigating related literatures.2. According to the literatures, metal tetrakis(p-sulphophenyl) porphyrins [Me TPPSO3H] and chitosan-immobilized metalloporphyrin catalyst materials (Me TPPSO3-H3+N-CTS) were synthesized and prepared. In addition, the methods of operating ethylbenzene oxidation, of analyzing products and of evaluating catalytic activity for the catalysts are described in details.3. The structure of the biomimetic catalyst materials were characterized using a variety of spectroscopy technique, such as UV-Vis and FT-IR spectra, thermogravimetric analysis(TG), X-ray diffraction(XRD) patterns and transmission electron microscope (TEM).4. The biomimetic catalyst materials were used for oxygen oxidation of ethylbenzene, The effects of various parametors, reaction temperature, reaction pressure, amount of catalyst and reaction time on the oxidation are discussed. In an optimum reaction conditions, the catalytic performance of three chitosan-supported catalyst materials are compared to one another. At the same time, the catalytic efficiecy of the supported catalysts reused for the oxidation are compared with those of the corresponding unsupported metalloporphyrins.5. The experimental results show that the catalytic performance and efficiency of the supported catalyst materials are better than those of the corresponding metalloporphyrins under optimum oxidation conditions. Only a small amount of the supported catalyst could be reused5times, to give33.0%of ethylbenzene conversion,82.7%of selectivity and27.3%of yields (alcohol and ketone).6. After investigating literatures and analyzing experimental results, a catalysis mechanism of ethylbezene oxidation over Me TPPSO3-H3+N-CTS is deduced to possibly being a free radical reaction.