H. Artigas

Thermophysic comparative study of two isomeric pyridinium-based ionic liquids.

A comprehensive thermophysical study of isomeric room-temperature ionic liquids n-butyl-3-methyl-pyridinium tetrafluoroborate and n-butyl-4-methyl-pyridinium tetrafluoroborate has been performed. This paper reports various experimental data including density, speed of sound, refractive index, surface tension, isobaric molar heat capacity, and kinematic viscosity. From the experimental results, coefficients of thermal expansion, dynamic viscosities and molar refractions of the studied ionic liquids have been determined. Results have been analyzed paying special attention to the different features of the isomers and their structural differences. Several theories and empirical relations have been applied in order to predict physical properties of ionic liquids. A good agreement between experimental and calculated data has been found. Furthermore, a study about the versatility and application of the different relationships has been carried out finding that in general density and coefficients of thermal expansion can be estimated with relatively good accuracy.

Excess thermodynamic properties of isomeric butanols with 2-methyl-tetrahydrofuran

Abstract Excess molar volumes, VmE, excess isentropic compressibilities, gkSE, of 1-butanol, 2-butanol, 2-methyl-1-propanol or 2-methyl-2-propanol with 2-methyl-tetrahydrofuran have been determined at the temperatures 298.15 K and 313.15 K. Excess molar enthalpies, HmE, for these mixtures are given at 298.15 K. The results obtained here are compared with those of 1-butanol or 2-butanol with tetrahydrofuran.

Speed of sound and isentropic compressibility of the ternary mixture (2-Butanol + n-Hexane + 1-Butylamine) and the constituent binary mixtures at 298.15 K and 313.15 K

Abstract Densities and speeds of sound for (2-Butanol + n -Hexane + 1-Butylamine) at 298.15K and 313.15 K, and the constituent binary mixtures (2-Butanol + n -Hexane), (2-Butanol + 1-Butylamine) at 298.15 K and 313.15 K, and ( n -Hexane + 1-Butylamine), at 313.15 K have been measured. The isentropic compressibilities, the excess isentropic compressibilities, and the speeds of sound deviations have been calculated for both the binary and the ternary systems, from the experimental data. The isentropic compressibilities have been compared with calculated values from the Free Length Theory (FLT) and Collision Factor Theory (CFT).

Excess molar enthalpies of 1,3-dioxolane, or 1,4-dioxane with isomeric butanols

Using a flow-mixing calorimeter, excess molar enthalpies of 1,3-dioxolane, or 1,4-dioxane, with isomeric butanols were determined at the temperatures of 298.15 K and 313.15 K. All the studied systems show positive excess molar enthalpies. The results are compared with calculated values from the UNIFAC model.

Excess properties of the ternary system cyclohexane + 1,3-dioxolane + 1-butanol at 298.15 and 313.15 K

Densities, speeds of sound and heats of mixing for the ternary system cyclohexane + 1,3-dioxolane + 1-butanol have been measured at atmospheric pressure at the temperatures of 298.15 and 313.15 K. Excess molar volumes, excess isentropic compressibilities and excess molar enthalpies have been calculated from experimental data and fitted by Cibulka equation. Excess molar properties were analysed in terms of molecular interactions and structural and packing effects.

Viscosities of 1-chlorobutane and 1,4-dichlorobutane with isomeric butanols at 25 and 40°C

This paper reports viscosities and excess viscosities for binary systems of 1-chlorobutane and 1,4-dichlorobutane with isomeric butanols at 25 and 40°C. Results show negative deviations from ideal behavior. Viscosities and excess viscosities were correlated by means of the Grunberg-Nissan equation and the Redlich-Kister equation.

Excess molar enthalpies for isomeric chlorobutanes with isomeric butanols

Abstract Excess molar enthalpies for mixtures of each of the isomers of chlorobutane with each of the isomers of butanol were determined at the temperature 298.15 K and atmospheric pressure. Excess molar enthalpies are positive for all the mixtures. The results are discussed in terms of molecular interactions.

Vapour-liquid equilibrium for the binary systems of 2-methyl-1-propanol with some halohydrocarbons at 40.0 and 101.3 kPa

A dynamic recirculating still was employed to measure isobaric vapour-liquid equilibrium at 40.0 and 101.3 kPa for the binary systems 2-methyl-1-propanol with some halohydrocarbons (chlorocyclohexane, chlorobenzene, bromocyclohexane and bromobenzene). Some of the studied systems show minimum temperature azeotropes. The experimental data were tested for thermodynamic consistency and satisfactorily correlated with the Margules, van Laar, Wilson, NRTL and UNIQUAC equations. Predictions with UNIFAC and ASOG methods were also obtained.

Densities and excess molar volumes of the ternary mixture (1-butanol+n-hexane+1-chlorobutane) at 298.15 and 313.15 K. Application of the ERAS model

Abstract Densities of the liquid mixtures (n-hexane+1-chlorobutane) and (1-butanol+n-hexane+1-chlorobutane) have been measured by the vibrating tube technique at 298.15 K and 313.15 K. With these densities, excess molar volumes were calculated. An extended version of the so-called ERAS model has been used for describing VE of the complete ternary system at 298.15 K. Qualitatively the ERAS-model gives an adequate representation of this system, being similar the shapes of both the experimental and the predicted curves.

Experimental data of isobaric vapour–liquid equilibrium for binary mixtures containing tetrahydrofuran and isomeric chlorobutanes

Isobaric vapour–liquid equilibrium (VLE) measurements for mixtures formed by tetrahydrofuran and isomeric chlorobutanes at 40.0 kPa (except for the mixture containing 2-methyl-2-chloropropane) and 101.3 kPa are reported. The activity coefficients were calculated from experimental data. The mixture containing 2-chlorobutane at 40.0 kPa presents an azeotrope. The VLE measurements have been found thermodynamically consistent according to Van Ness test. Wilson, NRTL, and UNIQUAC equations have been used to correlate the activity coefficients and we have obtained satisfactory results.