Oxygen separator peroxide-based

Fig. 8. Three-chamber peroxide-based oxygen separator.

The modification of the initiation step and the reaction mechanism is based on the high reactivity of the catalytic active transition metal complexes toward peroxides and peroxy radicals which are formed by autoxidation or from benzylic radicals which have been trapped by oxygen. To elucidate the combined complex reaction mechanisms, the impact of the single catalysts will be discussed separately. 

The central theme that the apoprotein facilitates the scission of the O—O bond is based on the established mechanisms of peroxide heterolysis 165). By invoking concerted proton transfer (s) in the transition state, such schemes illustrate that oxygen-oxygen heterolysis need not be attended by an electrostatically unfavorable charge separation. In addition, they offer some rationale for the observed high entropy of activation in the primary H202-catalase reaction (—25 cal mole" deg ) 166). This should be the case in a rigid lattice of interactions implied in Eq. (20) and formulas (VII) and (VIII). 

Particular attention has been devoted to the catalytic activity of palladium (Pd /Pd ) salts, mostly because of their high reactivity in mild conditions. The reaction can be driven toward the formation of oxalate or carbonate (9-1J). The reoxidation of Pd° salts with oxygen can be easily performed in-situ if a suitable co-catalyst is used. Copper has been the most widely proposed. Unfortunately, the formation of water during the reoxidation process heavily interferes with the catalytic cycle. Therefore, non-conventional oxidants like peroxides (J2) or processes involving a separate reoxidation step have been proposed. A vapor phase two-step process based on palladium catalyzed carbonylation of methyl nitrite has been developed on an industrial scale in Japan (13). 

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