Bach-Engler peroxide theory

In some cases the main portion of the final products is formed by decomposition of peroxides. This is the current aspect of the classic Bach-Engler peroxide theory with respect to the chain theory of oxidation processes. 

Hydrocarbons are oxidized without the introduction of a radical source but this oxidation occurs with autoacceleration. This autoacceleration was explained in the framework of the theory of degenerate-branched chain reactions by the formation of an intermediate product, initiator. It was proved in 1930-50 that these products are hydroperoxides (see above). The Bach-Engler peroxide theory was thus merged with Semenov s theory of degenerate branching. Soviet scientists made the decisive contribution to the development of this area. 

The peroxide theory of Bach [20] and Engler [23] fixed the phenomenon of peroxide formation as the primary product of hydrocarbon oxidation by dioxygen. However, the problem of the mechanism of peroxide formation remained unsolved. The new stage of successful study of organic compound oxidation began after the discovery of free radicals as active intermediates of many chemical processes. 

The years following Van t Hoff s publication [4] are known as a period of rapid progress in the study of multi-step chemical reactions. There appeared Ostwald s and Kistjakovskii s studies, Bach-Engler s peroxide theory, and Luther and Shilov s theory of conjugated reactions. The postulate claiming that "a reaction is not a single-act drama (Schonbein) had become a common belief. 

According to Bach and Engler s peroxide theory [43], the coupling in oxidation reactions is explained in terms of intermediate formation of a peroxide. If of two substances, A and B, only one (e.g.. A) reacts with molecular oxygen to give a peroxide (AOj) (substance A is then called an inductor ), then substance B ( acceptor ) may be oxidized by this peroxide ... 

A modification of Traube s theory was introduced simultaneously in 1897 by Bach 3 and by Engler and Wild,4 who laid emphasis on Traube s idea that the oxygen molecule combines as a whole, but extended its powers of combination to other substances than nascent hydrogen. In support of this, it was pointed out that sodium will burn on an aluminium plate to the peroxide, Na202, whilst rubidium is almost quantitatively converted into the peroxide, Rb02, in a similar manner.5... 

C. Engler and W. Wild supposed that in autoxidation reactions the oxygen molecule is not actually divided but is opened out into an active form —O—O—, which combines with the activator to form an unstable peroxide, e.g. with turpentine. F. Haber supposed that free radicals are formed. Modern research favours the Traube-Bach theory. ... 

In 1897 Engler and Bach [1] reported one of the earliest studies on thermo-oxidative degradation of materials. They developed a theory of oxidation leading to peroxides. 

Reversible, consecutive, and parallel reactions were described and examined by V.A. Kistiakovski in 1894. Three years later, A. N. Bach and G. Engler proposed the peroxide theoiy of oxidation and introduced the notion about a labile intermediate product, moloxide, in oxidation processes. N.A. Shilov studied the kinetics of various conjugated oxidation reactions and developed the theory of self-conjugated reactions. 

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