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In this work, the ISM equation of state based on statistical-mechanical perturbation theory has been extended to liquid refrigerant mixtures by using correlations of Boushehri and Mason. Three temperature-dependent parameters are needed to use the equation of state: the second virial coefficient, B 2 (T ), an effective van der Waals covolume, b(T ), and a scaling factor, α(T ). The second virial coefficients are calculated from a correlation based on the heat of vaporization, ∆H vap , and the liquid density at the normal boiling point, ρ nb . α(T ) and b(T ) can also be calculated from second virial coefficients by a scaling rule. The theory has considerable predictive power, since it permits the construction of the PVT surface from the heat of vaporization and the liquid density at the normal boiling point. The equation of state was tested on 33 liquid mixtures from 12 refrigerants. The results indicate that the liquid densities can be predicted to at most 2.8% over a wide range of temperatures, 170-369 K.

The major objective of this work was the development of a reliable model to describe volumetric properties of ionic liquids (ILs). In this regard, we have applied the Ihm-Song-Mason equation of state (EOS) to some phosphonium-and imidazolium-based ILs. Three temperature-dependent parameters in the equation of state have been scaled based on the surface tension and the liquid density at room temperature. In order to improve the predictive power of the mentioned EOS for ILs, we have proposed using a simple modification. We have taken 1,228 experimental points to show the reliability of the improved EOS. The comparison of predicted densities with literature data over a broad range of temperature, 293-472 K, and pressures up to 200 MPa led to encouraging results. The average absolute deviation of calculated densities from literature values was found to be 0.75%.

Key indicators: single-crystal X-ray study; T = 296 K; mean (C-C) = 0.009 Å; R factor = 0.068; wR factor = 0.144; data-to-parameter ratio = 12.9.In the title molecule, C 15 H 13 NO 2 S, an intramolecular O-HÁ Á ÁN hydrogen bond forms an S(6) ring motif. The benzothiazole ring system and the benzene ring form a dihedral angle of 8.9 (3) Å . In the crystal, molecules are linked by weak C-HÁ Á ÁO hydrogen bonds, forming chains along the b axis. In addition, -interactions [centroid-centroid distances = 3.772 (4) and 3.879 (4) Å ] are observed. Related literature