Comparative studies on oxidation of lignin model compounds with hydrogen peroxide using Mn(IV)-Me3TACN and Mn(IV)-Me4DTNE as catalyst

摘要: Abstract Comparative studies are conducted on the kinetics and reaction mechanism for oxidation of lignin model compounds, 1-(3,4-dimethoxyphenyl)ethanol ( 1 ), 1-(3,4-dimethoxyphenyl)-1-propene 2 ) E -1,2-diphenylethene 3 with hydrogen peroxide at temperatures below 80 °C using [LMn(IV)(μ-O) Mn(IV)L](PF 6 C - [L′Mn(IV)(μ-O) Mn(IV)](ClO 4 as catalyst. The disappearance rate in first phase -catalyzed increases up to temperature range 50–60 °C then decreases increasing temperature. cause slow down is not known. Based kinetic data products identified, found be more effective catalyst than , but less . In oxidation, oxidized corresponding α-carbonyl derivative while readily undergoes epoxidation conjugated double bond produce epoxides 5 anti-Markovnikov nucleophilic addition hydroxide hydroperoxide anions produced α,β-diol 7 benzaldehyde 8 which non-catalytic reactions determining steps. compound also aliphatic producing epoxide 9 However, none detected mixture. addition, susceptible expoxidation On basis reactions, catalytic cycles – postulated.