The experimental literature data and estimation by the modified UNIFAC method show that the most probable values for the limiting activity coefficient at 298.
Finally, limiting activity coefficients of benzene and alcohols in swelled LDPE calculated from constants in Table 2 were compared with values estimated from the modified UNIFAC [43, 53] assuming that the solvent is a hypothetical liquid hydrocarbon that has the same density as LDPE.
UNIFAC estimated molecules could be included, but they were always shown to extract with 100% yield.
As indicated in Table 4, 7 compounds were created with the group contribution method UNIFAC.
Rasmussen, Vapor-Liquid Equilibria Using UNIFAC
, Elsevier, Amsterdam (1977).
We are going to overcome this problem in future works by including the prediction of VLE by the modified UNIFAC (Dortmund) method .
With the further calculation of the VLE data by UNIFAC method, we will reduce the dependence of our model on external data.
For the cases where there was no agreement between the experimental and predicted data, in the future we will substitute the Flory-Huggins-based chemical potential by the UNIFAC equilibrium model, to verify if such cases can be better predicted.
kk] is the group interaction energy between like groups k and the group surface fraction [Mathematical Expression Omitted] is calculated from the UNIFAC (20) dimensionless surface area parameter, [Q.
The molecular reference volume, [Mathematical Expression Omitted] is calculated from the UNIFAC group reference volume parameter, [R.
The UNIFAC method was established to estimate the volatility of solvents and solvent mixtures (21,23-25).
To measure the phenomenon, the UNIFAC method has been established and the Shell Solvent Blend Evaporation Program developed by Shell Development Company (33).