Oxidation apparent termination rate constant

So, these reactions cannot lead to effective chain termination in oxidized alcohol. The decomposition of tetroxides depends on pH and apparently proceeds homolytically as well as heterolytically in an aqueous solution. The values of the rate constants (s 1) of tetroxide decomposition at room temperature in water at different pH values are given below [38,39],... 

Disproportionation of ester peroxyl radicals occurs very rapidly. Apparently, the ester group influences the rate constant of this reaction by increasing it. The rate constants of chain termination in oxidized esters are collected in Table 9.13. 

Cyclic chain termination with aromatic amines also occurs in the oxidation of tertiary aliphatic amines (see Table 16.1). To explain this fact, a mechanism of the conversion of the aminyl radical into AmH involving the (3-C—H bonds was suggested [30]. However, its realization is hampered because this reaction due to high triplet repulsion should have high activation energy and low rate constant. Since tertiary amines have low ionization potentials and readily participate in electron transfer reactions, the cyclic mechanism in systems of this type is realized apparently as a sequence of such reactions, similar to that occurring in the systems containing transition metal complexes (see below). 

Traylor and Russell (30) have shown recently that similar reactions for the cumyloxy radical are important in cumene oxidation at 60 °C., and Hendry (12) has provided some quantitative data. At low concentrations of hydrocarbon, Reaction 9 is favored over Reaction 7 (propagation by tert-BuO ), and significant numbers of methyl radicals are formed and converted to Me02 radicals. Chain termination thus shifts from the slow termination by 2 tert-Bu02 (Reaction 6) to Reaction 10, which has a rate constant several hundredfold larger (21). The apparent order of the oxidation in isobutane is then 3/2 a similar relation applies to gas-phase oxidations and is discussed there. 

Garton A, Carlsson DJ, Wiles DM. Polypropylene oxidation the apparent rate constant for per-oxy radical termination and the photoinitiation efficiency. Macromolecules 1979 12 1071-3. 

This classification of reactivity can be compared with the values of kp obtained from the apparent oxidizabilities and from the termination constants (Table I). For ethers, the order of reactivity above is the same as the order of kp. Similarly, the rates of oxidation of alkylbenzenes (11, 12) lead to the following classification. 

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