The Disproportionation Reaction And Kinetics Of Superoxide Anion In Different Solvents

Free radical(FR) is a kind intermediate of molecule, atomic group or anion with non-paired electrons. The superoxide anion (O₂) is the first product emerging in oxygen metabolism inside an organism, and it is also the precursor of all oxygen-containing free radicals. Under physiological conditions, the perfect and complicated enzymatic and non-enzymatic anti-oxidative protection systems in the organism enable the generation and disproportionation of O₂ inside the cell to be always balanced very well in organisms. The superoxide anion of physiological quantity has special physiological functions. But under some pathologic conditions, excessive generation or decreasing of disproportional ability of superoxide will occur, and the increase of superoxide concentration and oxidative damage will be taken place, which induces various diseases. Therefore, the study of the generation, examination and the disproportionation reaction kinetics of superoxide anion has an important significance for understanding the level control of O₂ inside organisms and the research on medicines for diseases correlated with oxidative damage.There are many approaches for the generation of superoxide anion, the more liable ones of which are xanthine-XOD, Pyrogallol autoxidation, adrenalin autoxidation method etc, and its examination methods include spectrometry, Electron Spin Resonance (ESR) or electrochemical method. Some of these methods require special instruments and highly expensive reagents; some will generate many intermediate products wich will interfere the measurements severely.In this thesis, we dissolved pure KO₂ in organic solvents such as DMSO, ionic liquids and acetonitrile, with 18-crown-6 as the complex solubilizer. As a result, the generated superoide anion was more pure, its state of stability could last for a longer period and UV spectrophotometric measure was more convenient and accurate. This stable superoide anion system was utilized to test the stability of O₂ in three different solvents mentioned above and determine the SOD-like activity of superoxide dismutase mimics (MSOD). The main research contents are listed as the following:1. N-methylimidazole, n-BuBr and NH₄BF₄ were used for the synthesis of the ionic liquid ([bmim]BF₄) for the solvent of superoxide. This kind of solvent has lower steam...