Study On The Electron Spin Resonance Of Porphyrin-Like Compounds And Their Activities On Liquid-Phase Oxidation Of Phenol

The preparation method of o-diphenol by liquid-phase oxidation of phenol with molecular oxygen at mild condition (30~60癈) was investigated in this dissertation, in which a series of porphyrin-like compounds were employed as catalysts. The Electron Spin Resonance (ESR) measurements have been performed on the catalysts.The effects of reactive conditions, such as amount of catalysts, reactive temperature, reactive time and reactant concentration, on the yields of o-diphenol were investigated. Experimental results demonstrate each factor has a different effect on the yields. And the optimal parameters for this reaction (M=lmol/l, R=0.6%, Tr=45癈) were obtained. On account of the cost-efficient, M=lmol/l, R=0.4% and Tr=45癈 were selected to investigate the activities of various catalysts. The activities of these catalysts are tetra-(o-nitrophenyl) metal porphyrins > tetra-(p-nitrophenyl) metal porphyrins > tetra-(o-chlorophenyl) metal porphyrins > tetra-(p-chlorophenyl) metal porphyrins > tetracarboxylic metal phthalocyanines > metal phthalocyanines. To the catalysts which have the same substituents and different metal ions, their activities are Co > Zn > Fe > Cu. Tetra-(o-nitrophenyl) cobalt porphyrins is the most active one among them, by which the yield of o-diphenol is 18.53%.The ESR spectrums for Fe, Co, Cu metal porphyrin complexes were measured at room temperature and 77K respectivly. Principal values of g tensor and hyperfine tensor A were determined from the spectrums. The number of unpaired electrons and the electronic structure of the metal ionswere obtained based on g and A.