Study On Catalytic Synthesis Of Phenol By Chloroperoxidase

Chloroperoxidase (CPO) because of its unique structure and activity center with a wide variety of catalytic activity, in recent years gained more and more widely used in organic synthesis. CPO crystal structure shows that the cytochrome P-450, horseradish peroxidase heme protein typically is different, CPO activity center "buried" in the molecule inside, direct access to difficult substrates heme CPO edge, you need to through a hydrophobic channel, but there is an opening in the top of hemoglobin connected with this channel, so that the substrate can be close CPO catalytic intermediate compound I of Fe4+=O+. Therefore CPO suitable substrate catalysis often some small organic molecules, be limited, CPO research in polymer synthesis is currently the only story. This article is part of the series of laboratory studies CPO enzymatic synthesis of polymers, based on enzyme-catalyzed polymerization of aniline on the polymeric phenol further research for the short comings of traditional chemical synthesis methods, the establishment of a mild, environmentally friendly green synthetic routes; systematically investigated the effect of the type and position of substituents, such as spatial effects and electronic effects on product synthesis, structure and try to resolve the polymerization reaction mechanism based on speculation-effect relationship. The main results obtained are as follows:Substituent effects of the type and location:This selection of phenyl phenol, methyl phenol,4-ethyl phenol, p-hydroxy cinnamic acid, isopropyl phenol and o-cresol and other substrates to study six object to Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR) and thermal gravimetric analysis, electrochemical analysis for the characterization means to yield a polymer, the degree of polymerization and thermal stability evaluation study substituent the impact of the polymerization reaction. The results showed that:In the vicinity of the para-substituted substituted with advantage away; while the alkyl-substituted group in the class electron substituted aryl group is more favorable compared to polymerization, and thermal stability is relatively increased, but with substituted groups increases, It does not help to improve the steric hindrance of polymer yield.2) On the template directed polymerization of small molecule synthesis and doping: a substrate of p-phenylphenol was added template ethylene benzene sulfonate, is added to the six different proportion to the reaction system, but found that the template effectively destroyed hydrogen product, and a polymerization degree such that the thermal stability of the product has not been satisfactory improvement; reaction system doped with small molecules such as elemental iodine, potassium perchlorate, perchloric acid, sodium iodide and potassium iodide after only phenylphenol cuprous iodide doped with small molecules has improved the electrochemical activity of the system, the resulting polymer was detected by cyclic voltammetry, redox potential irreversible.3) Effect of the addition of ionic liquids:introducing imidazoles and quaternary ammonium salts of the ionic liquid solvent to improve the yield, the greater the cationic group wherein the ionic liquid, the shorter the more hydrophobic beneficial enzyme-catalyzed polymerization conduct; ionic liquid dosage also affected, showing a "bell" type rule.4) Mechanism speculated:Chloroperoxidase catalyzed synthesis of poly phenol radical reaction to the course, the first generation of free radicals by the CPO H2O2catalytic oxidation, polymerization reactions between free radicals and the formation of a dimer with each other, and then again, and dimers another free-radical monomers to form a dimer by free radical and a radical transfer, through a free radical initiator so that free radicals and free radical coupling to form a three-part polymer to pass. This indicates that the polymerization reaction was actually performed in the body, and therefore are not subject to restrictions on the channel substrate CPO size of the substrate and the product produced by the.