Catalytic Oxidation Of Phenolic Compounds And The Performance Of Para-iodine Reaction

An efficient method for aerobic oxidation of 2,3,6-trimethylphenol to trimethyl-1,4-benzoquinone catalyzed by copper(II)nitrate is developed in water under halogen ions-free conditions.The conversion of 2,3,6-thrimethylphenol was almost complete,and the yield of three methyl-1,4-quinone was in mild condition to about 94%.The unsubstituted phenol and the phenol having an electron withdrawing group did not react.For phenols having an electron donating group such as an alkyl group,the product is an alkyl-substituted 4,4'-benzoquinone and dialkylphenol 4,4'-dihydroxybiphenyl compound for monoalkylphenol.The reactivity of the various alkylphenols with copper(II)nitrate can be shown in the following order: monoalkylphenol <di-alkylphenol<tris-methylphenol.Based on this result,the mechanism of free radical pathway is proposed.This study provides a safe system for the high activity and selective oxidation of2,3,6-trimethylphenol to trimethyl-1,4-benzoquinone by catalytic methods.Under the mild conditions,the use of I2 as an iodine reagent,molecular oxygen as an oxidant to water as a solvent to achieve the copper(II)catalyzed by a variety of phenols oxygen and oxygen efficient catalytic method.This study provides a method of iodizing green with aromatic iodine atoms.In summary,a simple,green and effective method for the iodination of aromatic phenols with water as solvent,oxygen as oxidant and elemental iodine as iodine has been developed.Copper(II)nitrate exhibits a very high catalytic activity and the direct iodination of various phenols to iodine phenol for the use of dioxins in water.A wide range of phenol derivatives has been tested that contain electron donating or electron withdrawing groups,indicating that this is suitable for the synthesis of p-iodophenol.