Naphthalene oxidation by peracetic acid catalysed by Mn(III) porphine‐like complexes: nature of intermediates and pathways of their formation

Manganese tetraazaporphines as effective catalysts for the nuclear oxidation of aromatics by peracetic acid

“…The dependence of h in MD on catalyst concentration (Table 1; Figure 2, curve 2) agrees with the hypothesis on the participation of Mn 5+ -oxene in quinone formation at stage ( 6), which we have proposed earlier 6 in competitive naphthalene and olefin oxidation catalysed by 6. 6 Indeed, according to Scheme 1, as the catalyst content was increased, the contribution of stage (7) to the overall transformations of intermediate 7 diminishes because of an increase in the stationary concentration of Mn-oxene, which in turn leads to a decrease in the h in MD value. At high catalyst contents (> 0.02 mol% for 3; Figure 2, curve 1) the promotion of reaction (4) with catalyst concentration may be lowered by a competitive reaction of catalyst degradation with the Mn peroxo complex (8).…”

“…It seems that the reaction of the molecular complex PMn(AcOOH)(L) with the second AcOOH molecule followed by the formation of a Mn peroxo complex is catalysed by PMnX. The dependence of h in MD on catalyst concentration (Table 1; Figure 2, curve 2) agrees with the hypothesis on the participation of Mn 5+ -oxene in quinone formation at stage ( 6), which we have proposed earlier 6 in competitive naphthalene and olefin oxidation catalysed by 6. 6 Indeed, according to Scheme 1, as the catalyst content was increased, the contribution of stage (7) to the overall transformations of intermediate 7 diminishes because of an increase in the stationary concentration of Mn-oxene, which in turn leads to a decrease in the h in MD value.…”

“…§ As shown in Figures 2 and 3 and in Table 1, the quinone yield strongly depends on the concentrations of both the catalyst and AcOOH even at full substrate conversion. ¶ The growth of menadione yield with increasing the [AcOOH]:[2-methylnaphthalene] ratio up to 5:1 (higher than it is necessary for ‡ The indirect proof of the structure of intermediate 8 as reported earlier; 3,6 additional data for the affirmation of the structure of 8 will be published later. § The rate of the reaction catalysed by 3 is too high to be measured by common methods.…”

“…In our studies of naphthalene oxidation catalysed by 6 3,6 and of olefin epoxidation catalysed by 1-5, [7][8][9] we have supposed that two types of highly reactive oxygen-containing complex are generated by the interaction of PMnX with AcOOH: the Mn V -oxene [PMn 5+ (O)(L)] and Mn-peroxo [PMn(O 2 )(L)] complexes. The latter is thought to play a key role in the oxidation of naphthalene to quinone via the formation of intermediate 7, which in turn produces intermediate 8 by the interaction with PMn 5+ (O)(L).…”

Biomimetic Homogeneous Oxidation Catalyzed by Metalloporphyrins with Green Oxidants

“…An enormous range of oxidants have been used as oxygen atom transfer reagents to the metalloporphyrins in the oxidations. These include iodosylbenzenes, peroxyacids, hypochlorite, hydroperoxides, N-oxides, hydrogen peroxide, monoperoxyphthalate and potassium monopersulfate et al [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] However, the selective oxidation by green oxidants such as molecular oxygen or hydrogen peroxide is more attractive because of its cost-effectiveness and environmentally-friendly nature of the oxidant. [38][39][40][41][42] The chapter will try to cover the biomimetic homogeneous oxidation of organic compounds catalyzed by metalloporphyrins with green oxidants based on our group's research works, in which the oxidized substrates include alkanes, olefins, alcohols, aldehydes, sulfides etc.…”