Synthesis Of 3,8-Substituted Protoporphyrin Derivates And Study Their Application Of The Cyclohexane Oxidation

One of important application of porphyrin derivatives are used as biomimetic catalyst in oxidation, and the catalytic activity and selectivity still need to be improved. Protoprophyrin derivatives are synthesized from heme, because of their closer relationship to monooxygenase P-450, theoretically, metallo-protoporphyrin derivatives have higher catalytic activities and selectivity. Study the biomimetic catalytic activity of the metallo-protoporphyrin derivatives should be helpful to develop and design the new and effective catalysts for oxidation. Therefore, the development of their new synthesis process has always been the focus of academies and enterprises. In the paper, we designed and synthesized a series of metallo-protoporphyrin derivatives which were used as catalyst base on heme.Protoporphyrin dimethyl ester was prepared from hemin by a two-steps reaction including demetalation, esterification reaction.3,8-diethyl deuteroporphyrin dimethyl ester was systhesized by reduction base on protoporphyrin dimethyl ester; Hematoporphyrin was prepared from hemin by a two step reaction including demetalation, HBr addition reactions; "One pot" method is used for preparing hematoporphyrin diether derivatives from hemin under ultrasound irradiation by HBr addition, substituion reactions; Iso-hematoporphyrin was systhsized by oxidation of borohydride (B2H6-THF) reaction. The optimum processee were obtained by optimized the experimental conditions, and the structures of productions were confirmed by ultraviolet sprectrum, nuclear magnetism and mass spectrum.The corresponding metalloporphyrin were systhesized by reaction with different metal salt. The catalytic activity of the metallo-porphyrins was studied in the oxidation of cyclohexane with air. The results indicated that both the stable and catalytic activity have been improved,compared with simple tetraphenyl-prophyrin. Cobalt 3,8-diethyl deuteroporphyrin dimethyl ester exhibited the highest catalytic activity in the reactions, and the conversion of cyclohexane decreased to 16.9% in 4.0 h. The catalytic mechanism of this reaction was preliminary studied by UV-vis spectrum.