Fugacity in the Liquid Phase

As discussed in Chapter 2, for noncondensable components, the unsymmetric convention is used to normalize activity coefficients. For a noncondensable component i in a multicomponent mixture, we write the fugacity in the liquid phase... 

The fugacity in the liquid phase is determined by methods we have seen previously. 

These considerations can be extended to reversible processes. They also apply to single phase, liquid systems. For the case, rather common in heterogeneous catalysts, in which one reactant is in a gas phase and the others and the products are in a liquid phase, application of the principles given above is straightforward provided that there is mass transfer equilibrium between gas phase and liquid phase, i.e., the fugacity of the reactant in the gas phase is identical with its fugacity in the liquid phase. In such case, a power rate law for an irreversible reaction of the form... 

Fugacities in the liquid phase may be defined as follows they are equal to fugac-ities in a vapour (gas) phase which is in phase equilibrium and which may be calculated by (4.454) or (4.458). It is because fugacities of a given constituent are the... 

The fugacity coefficient tpi of component i can be defined as the ratio of the fugacity in the liquid phase L (vapor phase V) to the product of the mole fraction x (y,) and system pressure P. In the vapor phase the product y,P can be substituted by the partial pressure pi. ... 

For the calculation of the chemical equilibrium conversion of reversible reactions in the liquid phase, the corresponding fugacities are required. For the description of fugacities in the liquid phase, in most cases activity coefficients yi are used (see Section 5.2) ... 

Since the standard thermodynamic properties for the ideal gas state were chosen, all standard fugacities are equal to 1 atm. The fugacities in the liquid phase can be expressed by (Eq. 12.28) ... 

In this section, we explore how we can calculate fugacity in the liquid phase. In doing so, we will develop an appropriate reference state for the liquid phase, the ideal solution, and then correct for real behavior through the activity coefficient. We will then learn a type of empirical model that correlates experimental data efficiently. The methodology developed in this section can also be applied to solids. Finally, an alternative approach to calculating fugacity in the liquid using PvT equations of state is discussed. This approach is similar to that used for the vapor phase in Section 7.3. 

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