Joback group contribution method

Devotta, S., and V. R. Pendyala, Modified Joback Group Contribution Method for Normal Boiling Point of Aliphatic Halogenated Compounds. Ind. Eng. Chem. Res., 1992 31, 2042-2046. 

The Joback group contribution method u.ses the following equations ... 

Specific isobaric heat capacities can be estimated with the Joback group contribution method [4]. The group contributions determine the coefficients of a polynomial of third degree ... 

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 ),... 

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). 

Input data Molecular structure and one measured vapor pressure value P)),eas, (often at a low pressure). The method requires estimation of and using a group contribution method. The original Pailhes method used the Lytrerson method [Lydersen, A. L., AlChE 21 (1975) 510], but the Joback method is illustrated here for consistency with the previous examples on critical constant estimation. 

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]. 

Estimation Methods for Critical and Other Properties 257 Table 6.9-1 Joback Group Contribution.s to Pure Component Propertie.s... 

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... 

Enthalpy of Formation The ideal gas standard enthalpy (heat) of formation (AHJoqs) of chemical compound is the increment of enthalpy associated with the reaction of forming that compound in the ideal gas state from the constituent elements in their standard states, defined as the existing phase at a temperature of 298.15 K and one atmosphere (101.3 kPa). Sources for data are Refs. 15, 23, 24, 104, 115, and 116. The most accurate, but again complicated, estimation method is that of Benson et al. " A compromise between complexity and accuracy is based on the additive atomic group-contribution scheme of Joback his original units of kcal/mol have been converted to kj/mol by the conversion 1 kcal/mol = 4.1868 kJ/moL... 

The compilations of CRC (2-3) Daubert and Danner (4) Domalski and Hearing (6) and Yaws (18-21) were used extensively. Estimates for enthalpy of fusion at the freezing point were primarily based on methods of Bondi (1, entropy), Joback (8, group contribution), and Chickos et al (11, group contribution). 

Vi is the number of occurrences of group i in the molecule. The values for the particular group contributions are listed on www.ddbst.com. The results for the representation of the data sets are reported to be superior to those obtained with other methods [12]. An evaluation with more than 2000 substances yielded average deviations of 16.5 K for the Joback method and only 1.5 K for the Rarey/Nannoolal method, which demonstrates the superiority of the latter one. 

Table 3.5 Group contributions for estimating Cp with the Joback method.

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