Synthesis And Catalytic Oxidation Activities Of Polymeric Quasi-porphyrin-Crown Ether Binuclear Complexes

The development of efficient catalysts for the selective oxidation of hydrocarbons in the presence of molecular oxygen under mild condition has remained to be a difficult challenge to the catalytic science.In this thesis, much attention has been paid to synthesis and catalytic oxidation properties of a new type of polymeric center-quasi-porphyrin-crown ether binuclear complex in which porphyrin or Salen Schiff base and crown ethers are combined in one polymer. As our respect, the function of complexes will be influenced when the crown ether is introduced into the polymer framework around the center of catalytic activity of complex, and the catalytic activities of polymeric complex will be improved by control circumstance-polymer surroundings for mimicking the structure and properties of enzyme. Meanwhile, the synthesis and catalytic activity of the polymer-bound tyrosine Schiff base complex was studied. It was revealed that crown ether can improve the catalytic activities of the catalyst and the heterogenization of homogeneous catalysts is a good way to render them practicable and improve stability, selectivity because of polymer environment. They can also be recovered and reused.1. Researches on the all kinds of complex catalyst metalloporphyrin catalytic system polymeric Salen Schiff-base and porphyrin complex, center-quasi-porphyrin complex modified by crown ether have been reviewed. The finding of efficient catalysis, especially metalloporphyrin and metal salen Schiff-base, for the oxidation of hydrocarbon is a topic of current research and receive much attention. In order to overcome some of the disadvantages of homogeneous catalysts, such as product contamination and difficult catalyst recovery, there are many important strategies to circumvent these problems: one is binding the metal complex to a polymer support or dispersing it in the pores of a suitable inorganic polymer support, another is polymerization of functional complex monomer. Recently, Schiff base and porphyrin containing a crown ether moiety have attracted special attention in the oxygen carriers and the study of oxygenation mechanism of biological systems and make greatprogress. Therefore, it is promising to realize heterogenization of metal complex and increase the catalytic activity and selectivity of the catalyst by condensation polymerization of center-quasi-porphyrin (porohyrin or salen Schiff base complex) with functional crown ether.2. The mononuclear and heterobinuclear polymeric complex based on porphyrin and crown ether has been successfully prepared by method of interfacial polymerization without presence of phase transfer catalyst owing to phase transfer property of crown ether. The films of the polymeric porphyrin and its complexes have two-dimensional structure and good thermal stability. According to the effect of temperature, additives and the amount of the catalyst used on the catalytic activity and the change product selectivity, especially the cyclohexene hydroperoxide acting as intermediate, the aerobic oxidation of cyclohexene happens on the allylic carbon in accordance with Haber-Weiss radical mechanism catalyzed by polymeric porphyrin-crown ether complex. Compare to mononuclear polymeric porphyrin complex without complexing the sodium cation in the crown ether cavity of the polymer, the polymeric porphyrin-crown ether heterobinuclear complex exhibit more excellent catalytic actitity, which suggested that introducing the sodium cation into the crown ether around the catalytic center of metalloporphyrin can improve the catalytic activity of the catalyst.3. The heterobinuclear polymer complex based on Salen Schiff-base complex (2OHCoSaleten, 2OHCoSalphen or 2OHCuSalphen) and crown ether has been successfully prepared by method of interfacial polymerization without presence of phase transfer catalyst, and the complex reaction of sodium cation complex in the cavity of crown ether occurred at the same time. The catalytic behavior of the polymeric Schiff-base-crown ether (Co-Na) heterobinuclear complex in aerobic oxidat...