Study On The Catalytic Activity Of Metal Tetra(4-hydroxy Phenyl)Porphyrin Immobilized On Graphene Oxide For Ethylbenzene Oxidation

Metalloporphyrin,being an important member of the biomimetic catalysts,posesses the catalytic ability for hydrocarbon oxidation with high efficiency and selectivity under mild reaction condition.However,the easy self-oxidation resulted in dimerization of metalloporphyrins in the catalytic process of oxidation reaction,and affected the catalytic activity.The further separation of them from the reaction mixtures come to be difficulty,and reuse of them changed to be impossible.The shortcomings can be improved by immobilization.Therefore,how to immobilize metalloporphyrin become the hot topics.This research work is about how to support metal tetrakis(4-hydroxy phenyl)porphyrin(M THPP)on graphene oxide(GO)via π-π interacting and double-hydrogen bonding between M THPP and GO,forming heterogeneous solid catalysts(M THPP/GO).The effect of graphene-oxide-immobilization on the catalytic performance of metal tetrakis(4-hydroxyphenyl)porphyrin(M THPP)for oxidation of ethylbenzene,especially the catalytic performance and stability of catalyts reused were investigated.The main contents of this research are as follows:1.Briefly summarizing the research progress about metalloporphyrin,graphene oxide and catalytic oxidation of ethylbenzene;2.synthesis of graphene oxide(GO),tetrakis(4-hydroxyphenyl)porphyrin(THPP),metal tetra(4-hydroxy phenyl)porphyrin(M THPP),and graphene oxide immobilized metal tetra(4-hydroxy phenyl)porphyrin(M THPP/GO)based on the literatures are researched and discussed.;3.Ultraviolet-visible spectroscopy(UV-Vis),Fourier transform infrared spectrum(FT-IR),X-ray photoelectron spectroscopy(XPS),specific area testing method(BET),thermogravimetric analysis(TG)and scanning electron microscope(SEM)and other technical methods were used for characterizing the catalysts.The structure,thermal stability and surface morphology,and the catalytic activities of supported metalloporphyrins were discussed and made conclusion via comparing their experimental data with those of the corresponding metalloporphyrins and grapheme oxide.4.The catalytic performances of the GO-immobilized catalysts for oxidation of ethylbenzene were explored under changing reaction temperature,pressure and catalyst amount,and their reusabilities were also studied under the optimal conditions.The immobilized metalloporphyrin catalyst shown better catalytic performance than the corresponding metalloporphyrin,the conversion rate of the Mn THPP/GO,Co THPP/GO and Fe THPP/GO was increased by 21.1%,6.4%and 5.9%respectively.The supported catalysts still remained good catalytic performance in five recycles,while the unimmobilzied metalloporphyrin could only be one-used off.5.After studing on the related experimental data combinded with related literautres,the mechanism of ethylbenzene oxidation over the metal tetra(4-hydroxy phenyl)porphyrins was infered as a free radical processs.