Topic
Activity coefficient
About: Activity coefficient is a research topic. Over the lifetime, 6020 publications have been published within this topic receiving 132928 citations.
Papers published on a yearly basis
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Papers
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.
3,169 citations
1,708 citations
TL;DR: In this article, sufficient thermodynamic data are available to permit calculation of equilibrium constants for a large number of hydrothermal reactions, where the calculations involve entropy estimates, application of average heat capacities, and/or assumptions concerning the temperature dependence of thermodynamic variables and the relative importance of electrostatic and non-electrostatic interaction among the species.
Abstract: Sufficient thermodynamic data are available to permit calculation of equilibrium constants for a large number of hydrothermal reactions. Where the data are incomplete, the calculations involve entropy estimates, application of average heat capacities, and/or assumptions concerning the temperature dependence of thermodynamic variables and the relative importance of electrostatic and non-electrostatic interaction among the species. Temperature stoichiometric activity coefficients for individual ions can be calculated using deviation functions computed from osmotic coefficients for concentrated NaCl solutions. The results of such calculations, together with computed heat capacities, enthalpies, entropies, and equilibrium constants for many hydrothermal species and reactions are presented in tables and diagrams.
1,560 citations
TL;DR: In this paper, the osmotic coefficients and mean activity coefficients of uni-univalent electrolytes in aqueous solutions at 25 °C were derived using the molality or weight basis.
Abstract: This paper gives values for the osmotic coefficients and mean activity coefficients of uni‐univalent electrolytes in aqueous solutions at 25 °C. The values are expressed on the molality or weight basis. The data available in the literature have been corrected to the presently accepted scales of atomic weights (1969) and temperature (IPST 1968) and, where necessary, to the absolute electrical units of 1969 and the fundamental constants of 1963. The selected values of osmotic coefficients and mean activity coefficients for individual electrolytes have been made internally consistent thermodynamically. In some cases estimated values are given; in other cases, references only are given when the data are sparse or unsuited to critical evaluation. Values of the osmotic coefficients and mean activity coefficients of 79 compounds are given together with the standard deviation, variance, and normalized standard deviation of their fit to equations which express these quantities as functions of electrolyte concentration. Finally, literature references are given to data on 51 additional uni‐univalent electrolytes.
1,206 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2026 | 3 |
| 2025 | 27 |
| 2024 | 56 |
| 2023 | 125 |
| 2022 | 251 |
| 2021 | 121 |