Joback and Reid method

Critica.1 Properties. Several methods have been developed to estimate critical pressure, temperature, and volume, U). Many other properties can be estimated from these properties. Error propagation can be large for physical property estimations based on critical properties from group contribution methods. Thus sensitivity analyses are recommended. The Ambrose method (185) was found to be more accurate (186) than the Lyderson (187) method, although it is computationally more complex. The Joback and Reid method (188) is only slightly less accurate overall than the Ambrose method, and is more accurate for some specific substances. Other methods of lesser overall accuracy are also available (189,190) (T, (191,192) (T, P ),... 

Method ofJoback and Reid The Joback and Reid method [15] applies for liquid hydrocarbons, halogenated hydrocarbons, and O-containing compounds ... 

Figure 6.3.1 Estimation of rjL at 35°C for 4-methyl-2-pentanone using the method of Joback and Reid [15].

Method of Jobaek and Reid The method of Joback and Reid, discussed in Section 6.3, allows temperature-dependent estimation of viscosity based solely on molecular structure input. 

Method of Joback and Reid The method of Joback and Reid [21] applies to AHv estimation at the normal boiling point only. It has been derived from a database of 368 compounds and fielded an average absolute error of 1.27 kJmol-1 corresponding to a 3.9 average percent error using the training set AHvb values. The GCM equation is ... 

Method of Joback and Reid The Joback and Reid model [10] has been based on a database of 388 organic compounds and yielded an average absolute error of 22.6 K, corresponding to a 11.2 average percent error for the retro-estimated Tm values of the training set. The GCM equation is... 

Suppose that the compound s phase at 25°C was of interest. This question would have been answered correctly for all three compounds, although the quantitative estimation of Tm is not very precise. Suppose that the compound s phase at 20°C was of interest. This question would have been answered correctly for cyclopropyl methyl ether and 1,2-cyclopentenophenanthrene, but not for anethol. The magnitude of the interval (7 m)estimated - Timerestl can serve as a confidence measure for binary decision of the foregoing type. If (7 m)estimated interestI is lower than 50°C, a decision as to whether a compound is fluid or solid at interest should not be made based on Tm estimated using the method of Joback and Reid. 

Clearly, this example demonstrates how important it is to recognize the structural difference between similar compounds and base property estimation on AStructure-ATm relationships instead of simply setting their Tm values equal to each other. Figures 10.4.2 to 10.4.6 illustrate similarity-based estimation of Tm using the method of Joback and Reid (Section 9.3). For comparison, the observed Tm values [4] for the query compounds are given below ... 

One of the most important contributions to this field was provided by Stein and Brown [117], who extended Joback and Reid s group contribution method [122], The authors calculated 85 group contributions and used a nonlinear quadratic equation to correctly predict BP at high temperatures. The authors calculated MAE = 15.5 K for a set of 4426 compounds and predicted another independent set of 6584 compounds with MAE = 20.4 K. The method was further parameterized by Syracuse Research Inc using 6484 compounds and was used in the MPBPVP program [101]. 

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. 

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... 

For performing estimations, the group contribution method of Joback and Reid [4] can again be used. The corresponding formulas are... 

Upon completion of data collection, estimation of the critical properties for the remaining compounds was performed using the group contribution method of Joback as given by Reid, Prausnitz and Poling (24). A comparison of the estimates with experimental data was favorable with average absolute errors of only 0.9%, 6.3 %, and 4.4% for critical temperature (465 compounds), pressure (453 compounds) and volume (345 compounds). 

Partial molar volumes and the isothermal compressibility can be calculated from an equation of state. Unfortunately, these equations require properties of the components, such as critical temperature, critical pressure and the acentric factor. These properties are not known for the benzophenone triplet and the transition state. However, they can be estimated very roughly using standard techniques such as Joback s modification of Lyderson s method for Tc and Pc and the standard method for the acentric factor (Reid et al., 1987). We calculated the values for the benzophenone triplet assuming a structure similar to ground state benzophenone. The transition state was considered to be a benzophenone/isopropanol complex. The values used are shown in Table 1. 

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