Synchronously Synthesizing And Immobilizing Porphyrins On Crosslinked Polystyrene Microspheres And Preliminary Study On Catalytic Activity Of Supported Metalloporphyrins

Metalloporphyrins biomimetic catalyst has been used to oxidate hydrocarbons with molecular oxygen; this is one of the most important domains of catalysis chemistry and organic chemistry at present. Especially, the heterogeneous catalyst is being paid more attention to. A new and convenient preparation method of Metalloporphyrins solid catalyzer has been designed in this paper, succeeding in realizing Synchronistic synthesis and immobilization of phenyl porpherin on crosslinked polystyrene microspheres (CPS). The Crosslinked polystyrene microspheres Immobilizing Phenyl porphyrin was prepared and then reacted with cobalt, producing Cobalt porphyrin catalyzer. The heterogeneous catalyst was used in the catalytic oxidation of ethyl benzene with molecular oxygen under ordinary pressure as oxidant, and some valuable research results were found.Firstly, the chloromethylation reaction of crosslinking polystyrene microspheres was performed at room temperature by using self-made chloromethylation reagent, 1,4-bis(chloromethoxy)butane. Then negative oxyanions coming from hydroxy benzaldehyde in water phase were transferred into organic phase by phase transfer catalyst (quaternary ammonium salt), and these Negative oxyanions were allowed to react with benzyl chloride groups of crosslinked chloromethylated polystyrene microspheres (CMCPS) which had been swelled in the organic phase, resulting in functional crosslinked polystyrene microspheres(HBA-CPS). The effects of various factors such as variety and amount of catalyst, solvent variety, the ratio of the organic phase to water phase, and reaction temperature on the phase transfer catalysis in the three phase-system of liquid- liquid-solid, and the reaction mechanism were investigated in detail. The experimental results show that the polarity of the organic solvent and its swelling property towards CMCPS microspheres are advantageous to the substitution reaction. The phase transfer catalyst with symmertry hydrocarbon chains on the quaternary ammonium ion and with stronger lipotropy has a better effect on the phase transfer catalysis. The ratio of the organic phase to water phase has also a significant influence on the result of phase transfer catalysis to a certain extent.By using 4-hydroxybenzaldehyde HBA-bound crosslinked polystyrene mocrospheres(CPS), pyrrole and benzaldehyde(4-chlorobenzaldehyde and 4-nitrobenzaldehyde substituted benzaldehydes) in a solution as co-reactants and through the Adler's reaction between solid-liquid phases, it was successfully realized to simultaneously synthesize and immobilize phenyl porphyrin PP (4-chlorophenyl porphyrin CPP, 4-nitrophenyl porphyrin NPP) on CPS mocrospheres, resulting in phenyl porphyrin-supported microspheres PP-CPS, CPP-CPS and NPP-CPS. In this investigation, the effects of the main factors on the process of synchronistic synthesis and immobilization of phenyl porpherin were studied. The experimental results show that the acidity of the catalysts, the polarity of the solvents and substituent on phenyl porphyrins affect the synchronistic synthesis and immobilization of porpherin greatly. As the catalyst with a pKa value in the region of 2.8-3.4 is used, the microspheres PP-CPS with a higher immobilization amount of porphyrin will be obtained. When the solvent with higher polarity is used, the obtained microspheres PP-CPS have a higher immobilization amount of porphyrin.The coordination reaction between the microspheres PP-CPS (CPP-CPS, NPP-CPS) and cobalt salt was also conducted, and the functional microspheres CoP-CPS, CoP-CPS and CoNPP-CPS were obtained. The catalytic activity of them for the oxidation of ethyl benzene by dioxygen was examined. The experimental results show that the solid catalysts can make dioxygen to be activated effectively, and obviously catalyze the transform of ethyl benzene into acetophenone. The catalyst behaves fine catalysis activity and selectivity, the yield of acetophenone at ordinary pressure of oxygen and 95℃in 12h can get up to 15%, and the content of another product,α-methyl benzoic alcohol, is very small. In comparison, the catalytic activity of CoNPP-CPS is the highest.