H Zarie - Department of Physical Chemistry, faculty of chemistry ,Bu-Ali Sina University, Hamedan, Iran
A Paknejad - Department of Physical Chemistry, faculty of chemistry ,Bu-Ali Sina University, Hamedan, Iran

Excess enthalpies (H E) of non-electrolyte liquid solution are of considerable importance formixing or separation processes in the chemical engineering and petroleum industries, becauseprovide useful information about structure and molecular interactions of the components inmixture [1]. Moreover, the (H E) data can be used for the evolution of thermodynamic modelsfor describing the behavior of solutions [2].In this paper, excess enthalpy have been predicted using the CK-SAFT equation of state.Statistical Associating Fluid Theory (SAFT) [3] has been extended to many real, molecular,and macromolecular fluids, having molar mass up to 100000. Under the SAFT framework,fluids are modeled as collections of spherical chain segments. SAFT uses five parameters todescribe a chemical species. Two of these parameters, (m and v00), describe the number ofsegments and volume of segments used to model the species, one parameter (u0) describes theLondon dispersion energy between species and for associating species, two parametersdescribe the strength of the association bond (ε/k) and the volume of the association site (κ).These parameters are typically determined by fitting to experimental vapor pressure andliquid density data.