Epoxidation of olefin using Mn(III) tetraphenylporphyrin complex as catalyst

摘要

Mangances(III)tetraphenylporphyrin acetate(Mn(III)(TPP)Oac)has been synthesized and characterized by C_9 H,N analysis,IR and electronic spectra.The electrochemical studies of the complex show a single quasireversible electron transfer process at E_p~c=0.620 V.Polyisoprene and polychloroprene were epoxidized using Mn(TPP)Oac comples as catalyst and NaOCI or PhIO as oxygen donor.Both polyisoprene and polychloroprene were epoxidized completely within 7 h using NaOCI as oxygen donors and in 12 h using PhIO as the oxygen donor.The reaction was monitored by IR spectroscopy.The peak at 1020 cm~-1 due to -CH=CH- disappears completely and a peak has been observed at 970 cm~-1,characteristic of oxiranes,indicating the complete conversion of the polyene to polyepoxide-Cyclohexene and styrene were epoxidised using Mn(TPP)Oac complex as catalst and NaOCI and PhIO as oxygen donors.Epoxidation of styrene is complete in 30 min with 100% yield of styrene epoxide using PhIO,whereas it takes 1 h for the completion of the reaction using NaOCI and gives mixed products with 59.71% styrene epoxide,21.89% benzaldehyde and 18.40% phenylacetaldehyde.Epoxidation of cyclohexene is complete in 1 h using NaOCI with 33.57% cyclohexeneoxide,13.01% of cyclohex-2-ene-1-ol and 53.42% of cyclohex-2-ene-1-one,whereas the reaction was only 31.22% completed in 1h using PhIO with 22.06% yield of 2-cyclohexeneoxide,4.23% of cyclohex-2-ene-1-ol and 4.93% of cyclohex-2-one.The reaction was monitored by using gas chromatography.