J. Technology and Education, Vol.13, No.2, pp.47-52, 2006
General Paper
Radical-chain auto-oxidation of cyclohexene initiated by superoxide ion
coordinating to Cr(III)porphyrin
Yoshihiro TSUDA*1, Sanae TAKIMOTO2 and Kohshin TAKAHASHI3
1Department of Chemistry and Biochemistry, Numazu National College of Technology
(3600 Ooka, Numazu 410-8501, Japan)
2Department of Chemistry and Biology Engineering, Fukui National College of Technology
(Geshi, Sabae 916-8507, Japan)
3Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
(Kakumamachi, Kanazawa 920-1192, Japan)
(Received August 28, 2006; Accepted October 16, 2006)
Abstract
Air oxidation of cyclohexene to cyclohexene oxide, 2-cyclohexene-1-one and 2-cyclohexene-1-ol proceeded using 5,10,15,20-tetraphenylporphyrinatochromium(III)chloride (Cr(III)(tpp)Cl) as a metalloporphyrin and insoluble zinc powder as a reductant. The role of Cr(tpp)Cl was investigated by adding 1-methyl- imidazole (1-MeIm) and 3,5-di-tert-butyl-p-hydroxyl-toluene (BHT) to this system. In this oxidation mechanism, a superoxide ion coordinating to Cr(III)(tpp)Cl was first produced via the reduction process of the Cr(III) porphyrin-O2 coordination compound to Cr(II)porphyrin-O2 compound by zinc powder, and second, the superoxide ion coordinating to Cr(III)(tpp)Cl abstracted hydrogen from one of two allyl positions of cyclohexene, initiating radical-chain auto-oxidation.
Key words: Cr porphyrin, radical-chain auto-oxidation, activated superoxide ion
