Secondary interfering reaction

This chapter shows practically all kinds of possible reaction interactions, which part may be united in a general idea of interference of chemical reactions. The notion of interference includes mutual intensification or weakening of the reactions for instance, the rate of primary reaction product formation decreases, whereas the rate of secondary, conjugated reaction product formation increases. Currently, the mutual influence of reactions synchronized in time and space will be taken for interfering chemical processes [1-3]. 

Let us discuss this principal difference of two induction systems, physical and chemical, more comprehensively. In any chemical system, physical processes associated with diffusion and activation of reacting substances proceed simultaneously with chemical transformations of reagents. Therefore, as chemical reaction is induced by the associated physical process shaped as diffusion or activation represents the potential ability of any chemical system, whereas chemical induction consists of, at least, two coherently synchronized chemical reactions. As shown below, synchronization of kinetic curves for interfering chemical reaction product yields differs radically from these curves for physical influence on the secondary chemical reaction. 

Nevertheless, equation (2.17) may help in determining the determinant and detecting the type of interrelated reactions from it. It should be noted here that, in the broad sense of the word, interrelated (interfering) reactions are only those proceeding via general intermediate substances, capable reagents, initiators or catalysts of secondary reactions. Otherwise, this class of reaction may be added to by consecutive reactions, which are not coherent. 

Figure 2.2 Theoretical kinetic curves for interfering reactions (primary 1 and secondary 2) of extreme (a) and asymptotic (b) type A is the phase shift.

Note that the X line in Figure 2.2b may be located above or below the 50% level of product accumulation from both interfering reactions or actor (inducer) and acceptor consumptions. Line location above the X line means that the greater part of the total, highly active intermediate particles (active sites) is consumed for secondary reaction product formation and, vice versa, when the line is below X level. 

Tladiation chemists have been aware for about 15 years that the presence of dilute solutes in liquid hydrocarbons can change the course of radiation chemical reactions by other than the normally expected secondary radical reactions. For example, Manion and Burton (40) in early work on the radiolysis of benzene-cyclohexane solutions, drew attention to the possibility of energy transfer from solvent to solute. Furthermore, it is known that in hydrocarbon solvents certain solutes are capable of capturing electrons, thus interfering with the normal ion-recombination process (14, 20, 65, 72). Though ionic products can be observed readily in hydrocarbon glasses [e.g., (19, 21)] demonstration of effects which can be specifically ascribed to electron capture in the liquid state has been elusive until recently. Reaction of positive ions prior to neutralization can play an important role as demonstrated recently by studies on... 

Another way of rejecting polyatomic interfering ions and the products of secondary collisions/reactions is to discriminate them by mass. As mentioned previously, higher-order multipoles cannot be used for efficient mass discrimination because the stability boundaries are diffuse and sequential secondary reactions cannot be easily intercepted. The only way this can be done is to utilize a quadrupole (instead of a hexapole or octapole) inside the collision/reaction cell and use it as a selective bandpass (mass) filter. There are a number of commercial designs using this approach, so let us take a look at them in greater detail in order to better understand how they work and how they differ. 

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