Constantinou and Gani

Method of Constantinou and Qani The approach of Constantinou and Gani [22] has been described for Tb in Section 9.3. The analog model for AHv at 25°C is  

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The basic GC-model of the Constantinou and Gani method (Eq. 1) as presented above provides the basis for the formulation of the solvent replacement problem as a MILP-optimization problem. For purposes of simplicity, in this chapter, only the first-order approximation is taken into consideration (that is, W is equal to zero). In this way, the functions of the target properties of the generated molecules (solvent replacements) are written as monotonic functions of the property values, thereby, leading to a linear right hand side of the property constraints (property model equation), as follows,... 

Here H 8 and F2 8 can be estimated using the Constantinou-Gani group contribution method (Constantinou and Gani, 1994). 

Summary Marrero and Gani Constantinou and Gani)j Joback and (4]... 

Choice of critical properties for the calulation of solubility (y) of solids in CO2 using the PR equation (1 - Ambrose with Tb Constantinou Gani 2 - Ambrose with Tb Lydersen modified by Joback 3 - Lydersen modified by Joback 4 - Constantinou and Gani). 

Recommended Method The method of Constantinou and Gani is recommended with caution. 

The following group contributions have been taken from van Rrevelen and Hoftyzer (1976), Hansen and Beeibower (1971), and Constantinou and Gani (1994). 

Critical temperatures, critical pressures, and critical volumes can be estimated with group contribution methods. The most common ones are from Lydersen (1), Ambrose [2, 3), joback and Reid [4], and Constantinou and Gani (5). They are all explained in [6]. A recent development by Rarey and Nannoolal [7, 8) seems to be the most accurate one, but it is more difficult to apply. 

Although estimation methods for the acentric factor are available (e.g., group contribution method of Constantinou and Gani [11]), this concept is not recommended, as an estimation of co would only be a redundancy of the normal boiling point estimation. To avoid inconsistencies, it is recommended that co is always calculated by its defining equation 2.157. If the vapor pressure curve is unknown, the normal boiling point and the critical point can be estimated, and the Hoffmann-Florin equation or the Rarey/Moller method (Section 3.2.1) can be used to calculate the vapor pressure curve. 

The normal boiling point is an easily accessible physical property and has been measured for a large number of substances. In case that it is not available, the normal boiling point can be estimated with group contribution methods, for example, Joback and Reid [4] and Constantinou and Gani [5], analogously to the estimation of the critical point. The estimation formula for the Joback method is... 

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