Studies On Synchronously Synthsizing And Immobilizing Porphyrins On Cps Microspheres And Catalytic Character Of Immobilized Metalloporphyrins

As metalloporphyrin compounds simulate cytochrome P-450, the hydrocarbons catalytic oxidation can be achieved efficient and high selectivity under mild conditions, avoid the faults in the process of hydrocarbon selective oxidation.In this paper, succeeding in realizing synchronistic synthesis and immobilization of porphyrins on crosslinked microspheres CPS via the Adler reaction. Then the metalloporphyrin was produced reacted with metal ion. The polymer-supported catalyst was used in the catalytic oxidation of cyclohexane with molecular oxygen as oxidant, and some valuable research results for the field of heterogeneous biomimetic catalyst were found.Firstly, by using Kornblum oxidation method, the chloromethyl groups of chloromethylated crosslinked polystyrene (CMCPS) microspheres were oxidized with dimethyl sulfoxide (DMSO) as oxidant, and transformed to aldehyde (AL) groups, resulting in modified microspheres ALCPS. The effects of main factors such as reaction temperature, the amount of catalyst and the feed ratio on the modification reaction were investigated emphatically. The modified reaction need join the amount of KI treat as the catalyst and NaHCO₃ as earthbind acid agents, elevated temperature is helpful in the reaction, 1g chloric methylation crosslinked polystyrene microspheres (CMCPS, chlorinity 14%), with 20ml DMSO added 2.5g catalyst KI and 2g earthbind acid agents NaHCO₃ reaction 6 hours under 110℃, the aldehyde group-Function-alization Modif- ication conversion rate can amount to 88%.Synchronistic synthesis and immobilization of porphyrins on CPS microspheres were realized successfully by using benzaldehyde (or substituted benzaldehyde), pyrrole and the microspheres ALCPS as the co-reactants and via the Adler reaction between solid-liquid phases, obtaining three kinds of functional microspheres, on which phenyl porphyrin (PP), p-chlophenyl porphyrin (CPP) and p-nitrophenyl porphyrin (NPP) were immobilized(PP-CPS, CPP-CPS, NPP-CPS), respectively. The effect of the polarity and swellability of solvent and the acidity of the catalysts and the structure of benzaldehyde on the reaction were studied . The experimental results show that, as the temperature is 110℃, use the mixed solvent which has the stronger polarity and swellability (VDMSO:VXylene=1:1) and catalyst with a pKa value in the region of 3.0-3.9 is used, the porphyrin microspheres with a higher immobilization amount of 16.75g/100g will be obtained. In comparison, the synthesis of CPP-CPS using chlorobenzaldehyde is carried out most easily, while the synthetic NPP-CPS using nitrobenzaldehyde most difficult.Via the coordination reaction between the functional microspheres and metal ion(Co²⁺,Mn²⁺,Fe³⁺), nine polymer-supported metalloporphyrins were prepared. The metal ion content of solid catalyst was determined by the atomic absorption spectrometry. This paper mainly focuses on the catalytic activities of the four solid catalysts(CoCPP-CPS, CoNPP-CPS, MnNPP-CPS, MnCPP-CPS) in the catalytic oxidation reaction of cyclohexane by dioxygen, and the main factors on the catalytic activity were studied. The experimental results show that the metalloporphyrin catalyst can effectively activate dioxygen, has excellent catalytic activity and fine selectivity. The percent conversion of cyclohexane at ordinary pressure of oxygen and 40℃in 7h can get up to 45.16%. As the biomimetic catalyst, excess addition will inhibit the catalyst activity; the smaller the immobilization density on the surface of microspheres, the higher the catalyst activity is; and the catalyst has a good reuse performance. In comparison, the catalytic activity of MnNPP-CPS is the highest.