Re-examination and symmetrization of the adjustable parameters of the ERASmodel - Review on its formulation and application

This paper presents an intensive revision of the application of the extende d real association solution (ERAS) model for binary mixtures containing one or both self-associating compounds. We suggest new definitions for the com plexation constant K-AB and for the Flory's parameter X-AB, which involve a symmetrization of the model with respect to the change A <---->, B in addi tion to endow these parameters with a clearer physical meaning. The new exp resions for KAB and XAB also imply an extension of the model for applicatio n to any binary mixture exhibiting cross-association regardless of the rela tive degree of self-association of the components. A critical review on the formulation and application of the model is performed in order to clarify several disagreeing points in papers related to this matter. (C) 2000 Elsev ier Science B.V. All rights reserved.