Reaction Mechanisms Involving Radical Intermediates

Characteristics of Reaction Mechanisms Involving Radical Intermediates... 

SECTION 12,2. CHARACTERISTICS OF REACTION MECHANISMS INVOLVING RADICAL INTERMEDIATES... 

The situation is even more complex in the case of reaction related parameters. Independent of the appropriate reactor model, for complex reactions not only the reaction scheme but also the adequate type of rate equation for each reaction step has to be chosen before the parameters can be estimated. As a rule, in reaction engineering only the analytically measureable reactants (and reactions) should form the basis of the reaction network in contrast to physico-chemical research where the true" reaction mechanism (involving radical intermediates or active complexes) is sought. Certainly, the stoichiometry of the experimental product spectrum is important, but also the concentration/reactiontime dependencies like those given in Figure 6 are helpful. In contrast to parameter estimation and model discrimination, there exists no unique and straight forward analytic procedure for the built-up of even a simplified reaction scheme. The intuition of the chemical reaction engineer is therefore heavily relied upon. 

Intramolecular oxidative imidation of aromatic C-H bonds of A-arylamidines with DAIB leads to the formation of 2-substituted benzimidazoles in high yields. A reaction mechanism involving radical intermediates has been proposed (Scheme 15). ... 

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