Complex network of reactions

The basic mechanism was treated in a number of articles [6]. Following the light absorption, primary excited species are formed which can either recombine or migrate to the surface of the semiconductor, where several redox reactions may take place. Tlie organic substrate reacts widi formed active species (oxidant or reducing) depending on its initial oxidation state and the nature of substituents [7], forming radicals and other species that are further oxidized or reduced. Several complex networks of reaction have been reported on the basis of detailed chemical analyses of the time evolution of the substrate and formed intermediates or by-products [8-11],... 

We discussed the biosynthesis of glucose from simpler starting materials in chapter 12. The biosynthesis of other hex-oses is linked to glucose by a complex network of reactions (fig. 16.2). In fact, glucose serves as the precursor for the synthesis of many other hexoses without any rearrangement of the six carbon core. 

A complex network of reactions is hidden behind the simple stoichiometry of -butane oxidation (Equation 35). Butene, butadiene and furan have been suggested to be intermediates in a cascade of reactions eventually producing the anhydride. Carboxylic acids and carbon oxides are formed in parallel and consecutive oxidations. 

Figure 2.1 shows the formation of only one product. Most catalytic systems produce more than one product. Each additional product requires an additional loop in the mechanism, though generally the loops are joined by reaction pathways or by common catalytic intermediates. As we shall see, some of these systems can give complex networks of reactions. 

P. Glansdorff, Evolution of Complex Networks of Reaction, in Living Systems as Energy Converters (R. Buvet, M. J. Allen, and J. P. Massue, eds.), North-Holland, Amsterdam (1977), pp. 41-54. 

This approach was then appUed to determine the kinetic parameters of a more complex network of reactions, the nucleophilic aromatic substitution (Sj Ar) reaction of 2,4-dichloropyrimidine with morpholine (Scheme 4.6), where the... 

There is a general lack of fundamental information needed to extrapolate the results towards full scale process description. All known models do not take into account the rigorous and exhaustive description of the chemistry of thermal decomposition of polymers and describe the pyrolysis process by means of a simplified reaction pathway, while each single reaction step considered is not entirely representative of a complex network of reaction. 

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