Redistribution mechanism

An even closer parallel is found in the work of Kreilick (33, 34), who prepared the ketal derived from 2,6-di-tert-butyl-4-acetoxyphenol. From a study of the effect of temperature on line broadening in the NMR spectrum of this compound he concluded that rearrangement occurs both by dissociation to radicals and recombination and by a direct intramolecular process. The former corresponds to the key reaction of the redistribution mechanism, while the latter is entirely analogous to the ketal rearrangement mechanism (Reaction 15). 

The onset and duration of an induction dose of ketamine (Table 13—2) are determined by the same distribution/redistribution mechanism operant for all the other parenteral anesthetics. 

Figure 7.7 Schematic illustration of a) dissolution-precipitation and b) liquid redistribution mechanisms in a material containing a grain boundary glassy phase.

It was considered that the free phenoxy radical would lead to C-C coupling, and the C-O coupling would result from the phenoxy radical coordinated to the copper complex. A quinone-ketal intermediate, which could be formed by coupling of copper-mediated phenoxy radicals (the radical pathway b) or between phenoxonium cation and phenolate anion (the ionic pathway a), could explain both chain extension and redistribution mechanism. Therefore, the formation of quinone-ketal is proposed as key intermediate although it has never been detected in polymerization of 2,6-DMP. 

Sandberg and Allen [14] proposed a model (Fig. 2) for arsenic cycle in an agronomic ecosystem. This model contains 12 possible transfers to and from a field for the organoarsenical herbicides. They conclude that transfers involving reduction to methylarsines, soil erosion, and crop uptake were primary redistribution mechanisms in this model. From their data it was concluded that arsenic is mobile and nonaccumulative in the air, plant and water phases of the agronomic ecosystem. Arsenicals do accumulate in soil but redistribution mechanisms preclude hazardous accumulations at a given site. 

Wouters, M. (2006) Implementation costs and redistribution mechanisms in the economic evaluation of supply chain management initiatives. In Supply Chain Management An International Journal, 11(6), 510-521. 

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