General Laws Governing Substitution

The reduction scheme sketched by Haber for the reduction of nitrobenzene also holds true for the substitution products of nitrobenzene in so far as the formation of their reduction phases can be coordinated to the same reduction, condensation, or molecular rearrangement processes. But the decisive influ- 

Or this m.irrang m nt occur already in tin i fK -jihiiw, which leads to the mine result  

Since the tendency to form quinone derivatives is lacking in m-nitraniline, the nitroso- and hydroxylamine phase can unite normally to the, azo-body. 

For the same reason perhaps the exclusive formation of o- and p-amidophenol occurs  

These quinone derivatives, by further reduction, can produce only arnidophenols. If the quinone formation is prevented from taking place, for instance by esterifying the hydroxyl-group, the normal reaction to azoxy-bodies occurs, o- and p-Nitroanisol pass smoothly into azoxy- or azo-derivatives. The acylizing of the amido-group in the case of o- and p-nitroamines hinders likewise the quinone, and. therewith the amine, formation. The azoxy-body is smoothly formed, thus  

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DYNAMICS OF DISTRIBUTION The natural aqueous system is a complex multiphase system which contains dissolved chemicals as well as suspended solids. The metals present in such a system are likely to distribute themselves between the various components of the solid phase and the liquid phase. Such a distribution may attain (a) a true equilibrium or (b) follow a steady state condition. If an element in a system has attained a true equilibrium, the ratio of element concentrations in two phases (solid/liquid), in principle, must remain unchanged at any given temperature. The mathematical relation of metal concentrations in these two phases is governed by the Nernst distribution law (41) commonly called the partition coefficient (1 ) and is defined as = s) /a(l) where a(s) is the activity of metal ions associated with the solid phase and a( ) is the activity of metal ions associated with the liquid phase (dissolved). This behavior of element is a direct consequence of the dynamics of ionic distribution in a multiphase system. For dilute solution, which generally obeys Raoult s law (41) activity (a) of a metal ion can be substituted by its concentration, (c) moles L l or moles Kg i. This ratio (Kd) serves as a comparison for relative affinity of metal ions for various components-exchangeable, carbonate, oxide, organic-of the solid phase. Chemical potential which is a function of several variables controls the numerical values of Kd (41). 

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