Multiple reactions classification

Wheeler classified multiple reaction networks into three types in order to discuss the effect of diffusion on selectivity. In the present work, we use this classification to discuss selectivity effects with deactivation in general. Type I selectivity refers to two independent parallel reactions ... 

Systems of multiple reactions usually fall into one of four categories. These classifications are parallel, independent, series, and mixed series/parallel. Recognizing the structure of a multiple-reaction system frequently helps to identify the best approach to design or analysis. 

In an attempt toward electron-rich and electron-deficient multiple bonds as well as 1,3-dipoles, the triafulvene system may develop functionalization of a dipolarophilic, dienophilic, and diene component. Rigorous proof for a concerted or a stepwise mechanism, e.g. via dipolar intermediates, for any of the numerous reactions investigated cannot be presented. Therefore the following classification has been chosen from a more or less formal point of view. 

It is obvions that any categorization tends to name the main trait of the phenomenon under consideration. This is useful. At the same time, the categorization need not be understood literally becanse each effect possesses multiple characteristics. However, it is impossible to study anything withont even a minimal classification. In fact, investigations on the ion-radical electronic structure appear to be more developed than studies on their reactivity. Therefore, not every example considered here is snpplied with the reactivity description. However, future accomplishments in studies on ion-radical reactions will be better understood in terms of the principles stated here. 

A theoretical and experimental study of multiplicity and transient axial profiles in adiabatic and non-adiabatic fixed bed tubular reactors has been performed. A classification of possible adiabatic operation is presented and is extended to the nonadiabatic case. The catalytic oxidation of CO occurring on a Pt/alumina catalyst has been used as a model reaction. Unlike the adiabatic operation the speed of the propagating temperature wave in a nonadiabatic bed depends on its axial position. For certain inlet CO concentration multiplicity of temperature fronts have been observed. For a downstream moving wave large fluctuation of the wave velocity, hot spot temperature and exit conversion have been measured. For certain operating conditions erratic behavior of temperature profiles in the reactor has been observed. 

After entering all reaction data, a SMART assessment can be performed. The program then performs a series of mass-balance calculations and provides the waste quantification, hazard classification, and a qualitative level of concern. The algorithms cover single-step reactions that produce a single chemical product the software is not applicable to reactions with multiple products or for polymer reactions. In this case, the individual reactions of a synthetic sequence have to be calculated sequentially. 

The problem of classification of the reactions in organic catalysis belongs to another kind of structural problem of catalytic chemistry. Reactions of the molecules (and not with participation of radicals or ions) must first of all be distinguished according to their multiplicity doublet, triplet, etc. Herewith the bonds may be covalent or semipolar. 

A compilation of different catalytic stereoselective processes seems unnecessary for the purpose of a classification of the stereoselective syntheses. However, a few examples of some less frequently encountered catalytic kinetic resolutions and chiral catalyst mediated multiple stereodifferentiating reactions will be presented in Fig. 8. 

Palladium-catalyzed reactions have been widely investigated and have become an indispensable synthetic tool for constructing carbon-carbon and carbon-heteroatom bonds in organic synthesis. Especially, the Tsuji-Trost reaction and palladium(II)-catalyzed cyclization reaction are representative of palladium-catalyzed reactions. These reactions are based on the electrophilic nature of palladium intermediates, such as n-allylpalladium and (Ti-alkyne)palladium complexes. Recently, it has been revealed that certain palladium intermediates, such as bis-7i-allylpalladium, vinylpalladium, and arylpalladium, act as a nucleophile and react with electron-deficient carbon-heteroatom and carbon-carbon multiple bonds [1]. Palladium-catalyzed nucleophilic reactions are classified into three categories as shown in Scheme 1 (a) nucleophilic and amphiphilic reactions of bis-n-allylpalladium, (b) nucleophilic reactions of allylmetals, which are catalytically generated from n-allylpalladium, with carbon-heteroatom double bonds, and (c) nucleophilic reaction of vinyl- and arylpalladium with carbon-heteroatom multiple bonds. According to this classification, recent developments of palladium-catalyzed nucleophilic reactions are described in this chapter. 

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