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Group contribution method
About: Group contribution method is a research topic. Over the lifetime, 1133 publications have been published within this topic receiving 38070 citations.
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TL;DR: In this article, a group-contribution method is presented for the prediction of activity coefficients in nonelectrolyte liquid mixtures, which combines the solution-of-functional-groups concept with a model for activity coefficients based on an extension of the quasi chemical theory of liquid mixture (UNIQUAC).
Abstract: A group-contribution method is presented for the prediction of activity coefficients in nonelectrolyte liquid mixtures. The method combines the solution-of-functional-groups concept with a model for activity coefficients based on an extension of the quasi chemical theory of liquid mixtures (UNIQUAC). The resulting UNIFAC model (UNIQUAC Functional-group Activity Coefficients) contains two adjustable parameters per pair of functional groups.
By using group-interaction parameters obtained from data reduction, activity coefficients in a large number of binary and multicomponent mixtures may be predicted, often with good accuracy. This is demonstrated for mixtures containing water, hydrocarbons, alcohols, chlorides, nitriles, ketones, amines, and other organic fluids in the temperature range 275° to 400°K.
2,787 citations
TL;DR: In this paper, a modified UNIFAC (Dortmund, FRG) method was proposed to fit temperature-dependent group interaction parameters simultaneously to vapor-liquid equilibrium (VLE), liquid liquid equilibrium (LLE), h E, and γ ∞ data.
Abstract: Several years ago a modified UNIFAC (Dortmund, FRG) method was proposed, which shows various advantages when compared with the group contribution methods UNIFAC or ASOG; the latter are used worldwide for the synthesis and design of rectification processes. These advantages were reached by using a modified combinatorial part and by using a large data base to fit temperature-dependent group interaction parameters simultaneously to vapor-liquid equilibrium (VLE), liquid-liquid equilibrium (LLE), h E , and γ ∞ data. The main advantages of the modified UNIFAC method are a better description of the temperature dependence and the real behavior in the dilute region and that it can be applied more reliably for systems involving molecules very different in size. To increase the range of this applicability, the temperature-dependent group interaction parameters of the modified UNIFAC has been fitted for 45 main groups using phase equilibrium information (VLE, h E , γ ∞, LLE) stored in the Dortmund Data Bank. A comprehensive comparison with the results of other group contribution methods confirms the high reliability of the modified UNIFAC (Dortmund) method
1,279 citations
TL;DR: In this paper, the parameters for 46 group combinations are provided and a new main group for sulfones is introduced, for which the group interaction parameters for eight main groups are fitted.
Abstract: The group contribution method UNIFAC has become very popular because of its large range of applicability and its reliable predictions of vapor−liquid equilibria. With the help of new data stored in the Dortmund Data Bank (DDB), many gaps in the existing UNIFAC parameter matrix have been filled, and many new main groups have been added to the parameter table. In this paper, the parameters for 46 group combinations are provided. Additionally, a new main group for sulfones is introduced, for which the group interaction parameters for eight main groups are fitted.
1,135 citations
TL;DR: In this paper, a new method for the estimation of properties of pure organic compounds is presented, which uses contributions from simple groups that allow describing a wide variety of organic compounds, while the higher levels involve polyfunctional and structural groups that provide more information about molecular fragments whose description through first-order groups is not possible.
1,017 citations
TL;DR: In this paper, a new group contribution method for the estimation of properties of pure organic compounds is presented, which is performed at two levels: the basic level uses contributions from first-order groups, while the next higher level uses a small set of second order groups having the first order groups as building blocks.
Abstract: A new group contribution method for the estimation of properties of pure organic compounds is presented. Estimation is performed at two levels: the basic level uses contributions from first-order groups, while the next higher level uses a small set of second-order groups having the first-order groups as building blocks. Thus, the method provides both a first-order approximation (first-order group contributions) and a more accurate second-order prediction (first- and second-order group contributions). This article discusses methods for prediction of normal boiling point, normal melting point, critical pressure, critical temperature, critical volume, standard enthalpy of vaporization at 298 K, standard Gibbs energy, and standard enthalpy of formation at 298 K. The predictions are based exclusively on the molecular structure of the compound, and the method is able to distinguish among isomers. Compared to the currently-used methods, this technique demonstrates significant improvements in accuracy and applicability.
1,003 citations