Coupled homogeneous chemical reaction volume

The internal chemical coupling C-+C includes homogeneous reactions in a gaseous or aqueous phase, and transport processes driven by chemical forces, such as molecular or ionic diffusion, and those heterogeneous processes related to it that do not involve large-scale transport for example, certain types of surface reactions or interactions between particles in colloidal suspensions (O Melia, Chapter 16, this volume) that are driven primarily by electrochemical forces fall in the class of C->C interactions. 

It is possible to use our considerable background of homogeneous chemistry and chemical reactor design to ensure high selectivity in the reaction of the organic substance, while the coupled electrolysis removes the need to purchase redox reagent and minimizes the volume of effluent to be handled. 

A local thermodynamic state is determined as elementary volumes at individual points for a nonequilibrium system. These volumes are small such that the substance in them can be treated as homogeneous and contain a sufficient number of molecules for the phenomenological laws to be applicable. This local state shows microscopic reversibility that is the symmetry of all mechanical equations of motion of individual particles with respect to time. In the case of microscopic reversibility for a chemical system, when there are two alternative paths for a simple reversible reaction, and one of these paths is preferred for the backward reaction, the same path must also be preferred for the forward reaction. Onsager s derivation of the reciprocal rules is based on the assnmption of microscopic reversibUity. The reversibility of molecular behavior gives rise to a kind of symmetry in which the transport processes are coupled to each other. Although a thermodynamic system as a whole may not be in equUibrium, the local states may be in local thermodynamic equilibrium, all intensive thermodynamic variables become functions of position and time. The local equilibrium temperature is defined in terms of the average molecular translational kinetic energy within the small local volume. 

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