Phase Equilibria and Transport Phenomena

This chapter intends to summarize the general thermodynamic basics for selecting the pressure of a chemical reaction. The most important point may be the understanding of chemical equilibrium. Particularly for gas-phase reactions, the reaction kinetics can be a second driver for choosing high pressures. The influence of phase equilibria and transport phenomena is a widespread and complicated field, which for reasons of space can only be touched on some exemplary aspects. 

Particularly in the field of heterogeneous reactions, the above-mentioned basics of reaction equilibrium and kinetics need to be supplemented by some considerations on phase equilibria and transport phenomena. In a gas-phase reaction involving a solid catalyst, for example, the convective and diffusive transport of the reactants to and from the catalyst surface as well as the adsorption and desorption on and from the catalyst surface affect the progress of the reaction, thus the reaction itself is only one step of a complex sequence. 

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