Search

A detailed test of the group-contribution hole models is used to predict thermodynamic properties of pure n-alkanes aliphatic monoethanes, 1-Chloroalkanes and their mixtures with n-alkane. The model however, in spite of being universal is applicable only to a few properties and limited range of parameters.

Highlights: [•] New apparatus measuring liquid–liquid and solid–liquid-equilibria was constructed. [•] LLE data for isomeric C8 aliphatic ethers and nitromethane were measured. [•] Influence of the position of ether group on the solubility curve was discussed. [ABSTRACT FROM AUTHOR]

Densities of pure 1-butyl-3-methylimidazolium methylsulfate, [Cmim][MeSO], and its mixtures with methanol have been measured. Measurements were made with an accuracy of ±0.2 kg·m, using a vibrating-tube densimeter, over the temperature and pressure ranges (283.15-333.15) K and (0.1-35) MPa, respectively. The experimental densities for the pure ionic liquid and alcohol have been correlated by the Tait equation. The results for the { x[Cmim][MeSO] + (1 − x)MeOH} system have been correlated by a van Laar equation involving parameters that are dependent on temperature and pressure. Excess volumes have been obtained directly from the experimental densities, while isobaric expansivities, isothermal compressibilities, and related excess properties were calculated from the correlation equation. Exceptionally strong pressure and temperature influences on these properties were observed. [ABSTRACT FROM AUTHOR]

Abstract: Densities of pure ionic liquids, 1-hexyl-3-methylimidazolium methylsulfate [C6mim][MeSO4], 1-hexyl-3-methylimidazolium ethylsulfate, [C6mim][EtSO4], 1-butyl-3-methylimidazolium ethylsulfate [C4mim][EtSO4] and their mixtures with either methanol or ethanol, were measured at temperatures T/K=(283.15, 298.15, 313.15, 328.15) at ambient pressure. The excess volumes V E were correlated by the van Laar equation with the temperature-dependent parameters. Isobaric expansivity and excess isobaric expansivity were described as functions of temperature and composition. The negative deviations from ideal mixing were observed for excess volume V E and the excess isobaric expansivity α E. [Copyright &y& Elsevier]

Abstract: Pressure–density–temperature measurements of the following pure ionic liquids—1-butyl-3-methylimidazolium tetrafluoroborate, [C4mim][BF4], 1-butyl-3-methylimidazolium methylsulfate [C4mim][MeSO4] and 1-ethyl-3-methylimidazolium ethylsulfate [C2mim][EtSO4] were performed using a vibrating tube densimeter over the temperature range (283.15 to 353.15)K and the pressure range (0.1 to 35)MPa. Experimental densities have been correlated by the Tait equation with the temperature dependent parameters. The isobaric expansivity and isothermal compressibility have been calculated. The influence of the cation alkyl chain length and the character of anion on the measured properties were discussed. [Copyright &y& Elsevier]

Abstract: Solid–liquid, liquid–liquid and vapour–liquid equilibrium measurements for binary and ternary systems containing building blocks of biomass origin such as propionic acid, lactic acid and alternative solvents like carbon dioxide and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid have been carried out at 313.15K. The binary solid–liquid and liquid–liquid equilibrium measurements were performed at ambient pressure. The vapour–liquid equilibrium was studied in the range of pressure from 3.54 to 12MPa while ternary systems were examined at 9, 10 and 12MPa. The samples from the coexisting phases were taken and the compositions of both liquid and vapour phases were determined experimentally. The three-phase system was observed for lactic acid+ionic liquid+CO2 as well. The achieved results were correlated using the Peng–Robinson equation of state with the Mathias–Klotz–Prausnitz mixing rule. The set of interaction parameters for the employed equations of state and the mixing rule for the investigated systems were obtained. [Copyright &y& Elsevier]

Abstract: Vapour–liquid equilibrium measurements for binary and ternary systems containing carbon dioxide, 1-propanol, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquids are presented in this work. The binary CO2 +1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide system at 313.15K at pressure range from 2 to 14.4MPa was examined. The obtained phase envelop shows that even at low pressure of CO2 the solubility of the gas in the ionic liquid is high. The ternary phase equilibria were studied at 313.15K and pressures in the range from 9 to 12MPa. The ternary phase diagrams show that higher CO2 pressure diminishes the miscibility gap. The experimental samples from the coexisting phases were taken and compositions of both liquid and vapour phases were determined experimentally. The results were correlated using the Peng–Robinson and the Soave–Redlich–Kwong equations of state with the Mathias–Klotz–Prausnitz mixing rule. The set of interaction parameters for the employed equations of state and the mixing rule for the investigated systems were obtained. [Copyright &y& Elsevier]

Abstract: Accurate excess molar volumes (V E), at ambient pressure and 303.15K, have been determined in the ternary liquid mixtures of N,N-dimethylformamide (DMF)+2-pentanone (PE)+1-alkan-1-ols (C3–C6) and in the binary mixtures of PE+alkan-1-ols (C3–C6) as a function of composition. The alkanols include 1-propanol, 1-butanol, 1-pentanol and 1-hexanol. The intermolecular interactions and structural effects were analyzed on the basis of the measured and derived properties. Excess molar volumes increase in magnitude with increase in chain length of alcohol. Valuable information on the behavior and governing factors of the liquid structure of the strongly associated solvents studied were inferred from the parameters deduced. The V E results were correlated and fitted by the Redlich–Kister equation for binary mixtures and by the Cibulka equation for ternary mixtures, as a function of mole fraction. Several predictive empirical relations were applied to predict the excess volumes of ternary mixtures from the binary mixing data. An analysis of the data indicates a good agreement between experimental results and predicted values in all ternary systems. A discussion is presented and deviations are interpreted in terms of size, shape, the position of ketone group, the chain length of alkanol and hydrogen bond effects in the liquid mixtures studied to explain chemical and thermophysical behavior. [Copyright &y& Elsevier]