@article{alves_capanema_chen_gratzl_2003, title={Comparative studies on oxidation of lignin model compounds with hydrogen peroxide using Mn(IV)-Me(3)TACN and Mn(IV)-Me4DTNE as catalyst}, volume={206}, ISSN={["1381-1169"]}, DOI={10.1016/S1381-1169(03)00448-5}, abstractNote={Comparative studies are conducted on the kinetics and reaction mechanism for the oxidation of lignin model compounds, 1-(3,4-dimethoxyphenyl)ethanol (1), 1-(3,4-dimethoxyphenyl)-1-propene (2) and E-1,2-diphenylethene (3) with hydrogen peroxide at reaction temperatures below 80 °C using [LMn(IV)(μ-O)3Mn(IV)L](PF6)2 (C-1) and [L′Mn(IV)(μ-O)3Mn(IV)](ClO4)2 (C-2) as catalyst. The disappearance rate of 1 and 2 in the first phase of C-1-catalyzed oxidation increases up to the temperature range of 50–60 °C then decreases with increasing reaction temperature. The cause for the slow down of the disappearance rate is not known. Based on the kinetic data and reaction products identified, C-1 is found to be more effective as catalyst in the oxidation of 1 and 2 than C-2, but less effective in the oxidation of 3. In the C-1- and C-2-catalyzed oxidation, 1 is oxidized to the corresponding α-carbonyl derivative 4, while 2 readily undergoes epoxidation of the conjugated double bond to produce the corresponding epoxides 5 and 6. The anti-Markovnikov nucleophilic addition of hydroxide and hydroperoxide anions on 5 and 6 then produced α,β-diol 7 and benzaldehyde derivative 8, which are non-catalytic reactions and rate determining steps. The compound 3 also undergoes epoxidation of conjugated aliphatic double bond producing the corresponding epoxide 9. However, none of the corresponding α,β-diol and benzaldehyde derivative is detected in the reaction mixture. In addition, 2 is more susceptible to expoxidation than 3. On the basis of the kinetics and reaction mechanism of the reactions, the catalytic cycles of the C-1- and C-2-catalyzed oxidation of 1–3 are postulated.}, number={1-2}, journal={JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL}, author={Alves, V and Capanema, E and Chen, CL and Gratzl, J}, year={2003}, month={Oct}, pages={37–51} }