Group-contribution estimation of activity coefficients in nonideal liquid mixtures

Authors

  • Aage Fredenslund,

    1. Department of Chemical Engineering University of California Berkeley, CA 94720
    Current affiliation:
    1. Instituttet fur Kemiteknik, The Technical University of Denmark, DK2800 Lyngby, Denmark
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  • Russell L. Jones,

    1. Department of Chemical Engineering University of California Berkeley, CA 94720
    Current affiliation:
    1. Union Carbide Corporation, S. Charleston, West Virginia
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  • John M. Prausnitz

    Corresponding author
    1. Department of Chemical Engineering University of California Berkeley, CA 94720
    • Department of Chemical Engineering University of California Berkeley, CA 94720
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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.

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