Abstract: Catalysis and substituent effects of monomanganese-porphyrins and monoiron-porphyrins with different substituents on the phenyl rings for α-pinene oxidation with air were studied. The results showed that the product mixture was composed of components resulting from the oxidation of C=Cbond and allylic secondary and primary C-H bonds in α-pinene. No oxidation products of allylic tertiary C-H bond were detected. the main component of the product mixture was α-pinene oxide. The yields of various oxidation products increased linearly with the increase of the reaction time when α-pinene oxidation was catalyzed by the experimental mentallo-porphyrins. With increasing the electron-donating abilities of the substituents on the meso sites of phenyl rings of monomanganese-porphyrins and monoiron-porphyrins, their catalytic activities was weakened and the conversions of α-pinene decreased. There were linear relationships between the reaction kinetic constant k and the substituent constant σ of the two kinds of metallo-porphyrins, and the Hammett equations: lnk=1.2168σ-7.9968 for monomanganese-porphyrins and lnk=0.6251σ-8.2426 for monoiron-porphyrins. The linear coefficients were 0.950 7 and 0.971 5, respectively.

Key words: α-Pinene, Metallo-porphyrins, Catalysis, Oxidation, Substituent effect