Application of SAFT-VR Equation of State for Prediction of Thermophysical Properties of Sugar Solutions

Thermophysical and rheological properties of sorbitol + ([mmim](MeO)2PO2) ionic liquid solutions: Solubility, density and viscosity

In this study, the solubility, density and viscosity of sorbitol as a sugar alcohol in the ([mmim](MeO)₂PO₂) ionic liquid (IL) were measured. The results indicated that sorbitol is highly soluble in this IL. The Flory-Huggins model with an average value for the χ parameter was successfully applied to predict the solubility of sorbitol in IL. The thermodynamic properties such as enthalpy, entropy and Gibbs free energy of dissolution were obtained using experimental solubility data, which demonstrated that the dissolution process is endothermic and non-spontaneous and includes an entropy increase. In addition, the apparent molar volume, apparent molar expansion and thermal expansion coefficient were calculated. The study of the rheological behavior revealed that the sorbitol/IL solution is Newtonian and the Arrhenius, Litovitz, Orrick-Erbar-Type and Vogel-Fulcher-Tamman models were used to correlate the viscosity data.

Flexible heuristic algorithm for automatic molecule fragmentation: application to the UNIFAC group contribution model

A priori calculation of thermophysical properties and predictive thermodynamic models can be very helpful for developing new industrial processes. Group contribution methods link the target property to contributions based on chemical groups or other molecular subunits of a given molecule. However, the fragmentation of the molecule into its subunits is usually done manually impeding the fast testing and development of new group contribution methods based on large databases of molecules. The aim of this work is to develop strategies to overcome the challenges that arise when attempting to fragment molecules automatically while keeping the definition of the groups as simple as possible. Furthermore, these strategies are implemented in two fragmentation algorithms. The first algorithm finds only one solution while the second algorithm finds all possible fragmentations. Both algorithms are tested to fragment a database of 20,000+ molecules for use with the group contribution model Universal Quasichemical Functional Group Activity Coefficients (UNIFAC). Comparison of the results with a reference database shows that both algorithms are capable of successfully fragmenting all the molecules automatically. Furthermore, when applying them on a larger database it is shown, that the newly developed algorithms are capable of fragmenting structures previously thought not possible to fragment.