Liquid phase equilibria for mixtures of (an aliphatic hydrocarbon plus toluene plus gamma-butyrolactone) at 298.2 K and atmospheric pressure

Liquid-liquid equilibrium (LLE) data for three ternary systems consisting of {n-heptane or n-hexane or cyclohexane (I) + toluene (2) + gamma-butyrolactone (3)} were measured at 298.2 K and atmospheric pressure. The reliability of the experimental tie-line data was verified by using the Othmer-Tobias correlation. Distribution coefficients, separation factors and selectivity were evaluated for the immiscibility region. The experimental tie-line data were correlated by the UNIQUAC equation and also predicted with the UNIFAC model. The calculated results were compared with the experimental data. Better agreement with the experimental data was obtained by the UNIQUAC equation. The UNIFAC model does not provide reasonable correlations. (C) 2009 Elsevier B.V. All rights reserved

Phase equilibria for ternary liquid systems of (water plus tetrahydrofuran plus nonprotic aromatic solvent) at T=298.2 K

(Liquid + liquid) equilibrium (LLE) data of the solubility curves and tie-line end compositions are presented for mixtures of {water (1) + tetrahydrofuran (2) + xylene or chlorobenzene or benzyl ether (3)} at T = 298.2 K and P = (101.3 +/- 0.7) kPa. Among the studied C6 ring-containing aromatic solvents, xylene gives the largest distribution ratio and separation factors for extraction of tetrahydrofuran. A solvation energy relation (SERLAS) has been used to estimate the (liquid + liquid) equilibria of associated systems containing a nonprotic solvent. The tie-lines were also predicted using the UNIFAC-original model. The reliability of both models has been analyzed against the LLE data with respect to the distribution ratio and separation factor. SERLAS matches LLE data accurately, yielding a mean error of 9.9% for all the systems considered. (C) 2005 Elsevier Ltd. All rights reserved

Isobaric (vapour + liquid) equilibrium for (2-propanol +water + ammonium thiocyanate): Fitting the data by an empirical equation

Isobaric (vapour + liquid) equilibrium (VLE) data for {2-propanol (1) + water (2) + ammonium thiocyanate (3)} were obtained at 101.3 kPa experimentally. An all-glass Fischer-Labodest type still capable of handling pressures from (0.25 to 400) kPa and temperatures up to 523.15 K was used. (Vapour + liquid) equilibrium data of (2-propanol + water) were also obtained at 101.3 kPa experimentally. An equation is proposed to fit the data of salt-containing systems using dimensionless groups called relative ratio. The proposed model was also tested for the salt-containing systems given from the literature. (c) 2006 Elsevier Ltd. All rights reserved

The Use of Poly(dodecyl methacrylate-co-N-isopropylacrylamide) Gel for the Separation of Limonene plus Linalool Mixture

Poly(dodecyl methacrylate-co-N-isopropylacrylamide) gels were prepared with and without a pore former (PEG) in ethanol at 70 degrees C by free radical cross-linking polymerization method. These gels were used to separate limonene + linalool mixtures with different fractions. The selectivity values were higher than 1 for each gel synthesized with PEG and without PEG. In equilibrium, selectivity values of gels synthesized without PEG in 90/10, 80/20, and 70/30 limonene + linalool binary mixtures were calculated as 1.1, 1.9, and 2.1, respectively. The corresponding gels synthesized using PEG have selectivity values as 1.3, 1.9, and 2.2. Despite slightly effect of pore former on selectivity, it has a relatively significant effect in time regions before arriving equilibrium, giving the idea of selecting optimum time region to separate binary mixtures. Solubility parameter of the gel was predicted by group contribution methods to determine the relationship between selectivity and solubility parameter difference of binary combinations of limonene, linalool and gel. Solubility parameter difference calculated from Hoy method showed that the value of each solubility parameter contribution for gel-linalool binary was the lowest with the values of 0.02, 1.7, and 4.8 for disperse, polar and H-bonding contributions, respectively verifying the selectivity of the gels for linalool. The gel synthesized using PEG shows a swelling value change for temperatures higher than 40 degrees C in the direction of decreasing but the gel synthesized without PEG has approximately constant equilibrium swelling value (ESV). This result indicates that the use of a pore former may be an important parameter in the recovery process of the extracted components after the separation procedure