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The liquid-liquid equilibrium (LLE) curves for 2-phenylethan-1-ol (2-phenylethanol, 2PhEtOH) + octane, + decane, + dodecane, + tetradecane or + 2,2,4-trimethylpentane have been determined by a method of turbidimetry using a laser scattering technique. Experimental results reveal that the systems are characterized by an upper critical solution temperature (UCST), which increases linearly with the number of C atoms of the n-alkane. In addition, the LLE curves have a rather horizontal top and become skewed to higher mole fractions of the n-alkane, when its size increases. For a given n-alkane, UCST decreases as follows: phenol > phenylmethanol > 2-PhEtOH, indicating that dipolar interactions decrease in the same sequence. This has been ascribed to a weakening in the same order of the proximity effects between the phenyl and OH groups of the aromatic alkanols. DISQUAC interaction parameters for OH/aliphatic and OH/aromatic contacts in the investigated systems are reported. Phenol, or phenylmethanol or 2-PhEtOH, + n-alkane mixtures only differ by the first dispersive Gibbs energy interaction parameter for the (OH/aliphatic) contact. [ABSTRACT FROM AUTHOR]

The coexistence curves of liquid-liquid equilibrium (LLE) for the mixtures: phenylacetonitrile + heptane, + octane, + nonane, + cyclooctane, or + 2,2,4-trimethylpentane and for 3-phenylpropionitrile + heptane, or + octane are reported. Aromatic nitrile + alkane, + aromatic hydrocarbon or + 1 alkanol systems are investigated using a set of thermophysical properties: phase equilibria (solid-liquid, SLE, vapour-liquid, VLE and LLE), excess molar functions, enthalpies ( H m E ), isochoric internal energies ( U Vm E ), isobaric heat capacities ( C pm E ) and volumes ( V m E ), and the Kirkwood’s correlation factor. Due to proximity effects between the phenyl and the CN groups, dipolar interactions between molecules of aromatic nitriles are stronger than those between molecules of isomeric linear nitriles. Dipolar interactions become weaker in the order: 3-phenylpropionitrile > phenylacetonitrile > benzonitrile. Benzonitrile + aromatic hydrocarbon mixtures are characterized by dispersive interactions and structural effects. The latter are more important in systems with phenylacetonitrile. Structural effects are also present in benzonitrile + n -alkane, or + 1-alkanol + mixtures. The systems mentioned above have been studied using DISQUAC. Interaction parameters for contacts where the CN group in aromatic nitriles participates are given. DISQUAC describes correctly any type of phase equilibria, C pm E of benzonitrile + hydrocarbon mixtures and H m E of benzonitrile + cyclohexane, or 1-alkanol systems. Large differences encountered between theoretical H m E values and experimental data for some solutions are discussed. 1-Alkanol + benzonitrile mixtures are also investigated by means of the ERAS model. ERAS represents well H m E of these systems. The V m E curves of solutions with longer 1-alkanols are more poorly described, which has been explained in terms of the existence of structural effects. [ABSTRACT FROM AUTHOR]

Liquid–liquidequilibrium (LLE) temperatures versus composition for N,N-dimethylacetamide (DMA) + decane,+ dodecane, + tetradecane, + 2,2,4-trimethylpentane, + methylcyclohexane,or + cyclooctane mixtures have been measuredby means of the critical opalescence method using a laser scatteringtechnique. All the systems show an upper critical solution temperature(UCST). In the case of n-alkane mixtures, UCST increasesalmost linearly with the chain length of the n-alkane.Moreover, these solutions show higher UCST values than those withisomeric cyclic alkanes. Branching leads to a strong decrease of UCST.The symmetry of the LLE curves depends on the size and shape of thealkane. DISQUAC correctly represents the coordinates of the criticalpoints using interaction parameters available in the literature. [ABSTRACT FROM AUTHOR]

Data on density, ρ , speed of sound, c , and refractive index, n D , have been reported at (293–303.15) K for the N , N -dimethylacetamide (DMA) + CH 3 CO(CH 2 ) u − 1 CH 3 ( u = 1, 2, 3) systems, and at 298.15 K for the mixture with u = 5. These data have been used to compute excess molar volumes, V m E , excess adiabatic compressibilities, κ S E , and excess speeds of sound c E . Negative V m E values indicate the existence of structural effects and interactions between unlike molecules. From molar excess enthalpies, H m E , available in the literature for N , N -dimethylformamide (DMF), or N -methylpyrrolidone (NMP) + n -alkanone systems, it is shown: (i) amide-ketone interactions are stronger in DMF systems than in those with NMP; (ii) they become weaker when u increases in mixtures with a given amide. Structural effects largely contribute to H m E and are more relevant in mixtures containing NMP. The application of the Flory's model reveals that the random mixing hypothesis is valid in large extent for DMF solutions, while NMP systems are characterized by rather strong orientational effects. From values of molar refraction and of the product P int V m (where P int is the internal pressure and V m the molar volume), it is concluded that dispersive interactions increase with u , or when DMF is replaced by DMA in mixtures with a fixed ketone. [ABSTRACT FROM AUTHOR]