Photocatalytic Activity Of The Supported Metal Alkylthio Porphyrazines And Assemblies

Porphyrins are compounds with a macrocyclic structure and a delocalizable?-electron system.Their structures are similar to those of cytochrome P450 enzymes.They can mimic biological enzymes to activate reactive oxygen species produced by molecular oxygen under mild conditions,so it can be used in various types of oxidation reactions,This type of biomimetic catalytic system has the advantage of environmental friendly.Sulfur-containing azaporphyrins are porphyrin derivatives obtained by the peripheral introduction of the electron-rich sulfur substituents,They have strong absorption in the visible light region,and can effectively activate molecular oxygen to generate reactive oxygen species under the irradiation of visible light,and are applied to the oxidation of organics.This paper mainly studies the photocatalytic activity of supported metal alkylthio porphyrazine and alkylthio porphyrazine self-assembly.The main work of this thesis is as follows:1.ZnO/CoPz?hmdtn?₄ was obtained by loading cobalt tetra?2-hydroxymethyl-1,4-dithiin?porphyrazine?CoPz?hmdtn?₄?onto ZnO,and the photocatalytic activity of ZnO/CoPz?hmdtn?₄was studied by photodegradation of RhB as the model.The effects of the catalyst loading and illumination wavelength on this reaction was investigated.The experimental results show that the catalytic activity of ZnO/CoPz?hmdtn?₄ is much higher than pure ZnO,and there is a synergistic effect between CoPz?hmdtn?₄ and ZnO.Quenching experiments and electron paramagnetic resonance?ESR?tests show that the main reactive species in the photocatalytic process of the supported catalyst are hole?h⁺?,hydroxyl radical?·OH?,singlet oxygen?¹O₂?and super oxygen anion?O₂^-·?;while the main active species of the carrier ZnO are hole?h⁺?and hydroxyl radical?·OH?.2.Supported Mg-Al LDOs/CoPz?hmdtn?₄ was prepared by impregnation method using porous Mg-Al LDOs as carrier.The photocatalytic oxidation of benzylamine to imine by Mg-Al LDOs/CoPz?hmdtn?₄ was studied.Reaction conditions such as solvent,loading,illumination wavelength and intensity were optimized.The experimental results show that the best conversion of benzylamine reaches 84.9%with 5wt.%catalyst under visible light???420nm?,and the selectivity of N-benzylidenebenzylamine is 92.9%.Quenching experiments and ESR techniques show that the main reactive oxygen species in this photocatalytic process is ¹O₂;and POD-DPD technology and GC-MS analysis show that the photocatalytic reaction intermediates are hydrogen peroxide and NH-imine.3.Symmetrical zinc porphyrin?ZnPz?SHe-Im?₈?containing eight imidazole groups in the periphery is self-assembled with palladium chloride?PdCl₂?at a molar ratio of 1:4 in water.Transmission electron microscope?TEM?and scanning electron microscopy?SEM?tests showed that the self-assembled morphology was a porous chain structure in which the large and small spheres were cross-linked.This material was used for the selective oxidation of benzyl alcohol.Reaction conditions such as light intensity,oxygen pressure,reaction temperature and substrate concentration were carefully optimized.The highest bezoic acid selectivity?88.8%?was obtained when the molar ratio of substrate to catalyst at 50:1.