Design And Synthesis Of Metal Porphyrin Compounds Derived From Hemin For Catalytic Oxidation Of Hydrocarbons

Oxidation of hydrocarbons with air or dioxygen is an extremely important reaction in chemical industry. A wide variety of catalysts have been used during the oxidation process, especially, the biomimic catalysts have attracted more attention due to the advantages of the high-efficiency, green, energy saving. Metalloporphyrins, as models and mimics of enzymes like catalase, paroxidases, cytochrome P450, are widely and intensely investigated in the area of biomimic catalysis. Furthermore, hemin is firstly isolated from natural porphyrin and applied to various fields, such as organic synthesis, catalysis, material, biomedicine. etc. it’s very significant to study the oxidation of hydrocarbons catalyzed by hemin derivatives.In this thesis, deuteroporphyrin was firstly synthesized by two-step procedure including the devinylation of hemin and the demetalation of deuterohemin. The devinylation mechanism in molten resorcinol has been investigated by capturing the intermediate molecular weight. During the demetalation process, The influences of ratios of hydrochloric acid to (CH3CO)2O, bath temperature and reaction time on the reactions were also investigated, on the base of which the mechanism of demetalation and the effect of ultrasound irradiation on metal-ligand cleavage have been discussed in detail.A series of porphyrins derived from deuteroporphyrin, bearing with different type of substituents, was prepared by modification of the double propionate side chains. Those cobalt complexes have been investigated to clear the relationship between the catalytic activity and the structure of metalloporphyrin in the oxidation of toluene. The-SS-and-NH2groups have the unpaired electrons that are prone to bind the cobalt ion of porphyrin core by forming the intermolecular interaction in the reaction, and are benefit for promoting the electron delivery and improving the stability of intermediate species. In addition, the UV-vis spectroscopy has been used to study the oxidative degradation of porphyrin.Secondly, deuteroporphyrin-niacin dyads with different chain lengths have been synthesized by reaction of deuteroporphyrin with diol, niacin. In order to elaborate the intramolecular coordination, the spectra of single manganese porphyrin complexes in CH2Cl2solution were measured and compared to that of the addition of axial ligands (pyridine and methyl nicotinate). Among all the synthetic dyads, the Mn-DPDN and Mn-DAPPN bearing the short chains did not show intramolecular coordination of the terminal base on the metal ion. Other three compounds of the niacin moiety indirectly bonded to the propionate side chains of manganese porphyrin through the diols linkage exhibited optical spectra characteristic of five or six-coordinate manganese complexes. In oxidation of olefin, the six-coordinate Mn-DPEDN shows the better catalytic activity than five-coordinate Mn-DPBDN and Mn-DPDN.The (3-mono/dibrominated deuteroporphyrin dimethyl esters have been synthesized and investigated by comparison with tetraphenylporphyrin in oxidation of alkenes. It was found that the natural Mn-DPDME (Mn-DPPH) which has no substituents in the meso-sites but does have the methyl and propionate groups in the β-sites exhibited the higher activity than Mn-DPBR (Mn-TPP), however, the later showed the superior stability analyzed by TG-DTA. Among these catalysts, Mn-DPDME shows the best activity and100%selectivity of epoxide. In order to confirm the reactive intermediates indirectly, we have applied the mass spectrometer and UV-vis absorption spectroanalysis to the inference of the oxidized intermediates of Mn-DPDME in benzonitrile by the action of O2and styrene. Furthermore, we also studied the spectral properties of the four β-substituted deuteroporphyrin dimethyl esters with-NO2,-Br,-COCH3,-C2H5groups. The relationship between substituents and metalloporphyrin activity has been confirmed in oxidation of cyclohexene, and their stability have been compared by the method of high-energy collision-induced dissociation of tandem mass spectrometry, demonstrating the electron-withdrawing group can able to improve the stability of the metalloporphyrin.Once more, selective oxidation of cyclohexane, cyclohexene and alcohols was carried out for the first time in homogeneous system by using manganese porphyrin as an efficient catalyst. The reaction conditions and catalytic oxidation mechanism have been investigated. Taking M-PDTEP as an example, the best results were obtained27%cyclohexane conversion and89%selectivity in the presence of catalyst0.02mmol, temperature140℃, pressure0.7MPa, reaction time4.5h. Meantimes, under optimal reaction conditions of100℃,0.8Mpa,7h,7.6×10-4mmol Sn-DPDME and10mL cyclohexene, the obtained cyclohexene conversion and total selectivity of the corresponding products were84%and94%, respectively. The oxidation of alcohols to carbonyl compounds using dioxygen catalyzed by M(DPDME) in acetonitrile as the reaction solvent and isobutylaldehyde as cocatalyst has been investigated, and the mechanism for the aerobic oxidation of alcohols has been proposed and discussedFinaly, three kinds of supported catalysts, Mn(III)DPCl-CTS, SiO2&NH2&Mn/Sn-DP, Fe3O4&SiO2&NH2&Mn/Sn-DP, were prepared by convalent binding of metallo-deutero-porphyrin ring to CTS, SiO2and Fe3O4, respectively. Their structures and properties were investigated by UV-vis、FTIR、TG-DTA、TEM (SEM) and XRD. Under an optimum temperature of140℃and a pressure of0.7MPa, Mn(III)DPCl-CTS catalyzed the oxidation of the cyclohexane by air to give cyclohexanol and cyclohexanone with a modest yield of17%and selectivity of89%, and the supported catalysts kept its activity after consecutively reused five times. Other two supported catalysts were also found to be efficient catalysts for oxidation of alkenes in the presence of dioxygen, and the reactions proceeded well within1.5h at50℃in CH3CN solution to give more than98%conversion and92%selectivity.