Excess Refractive Index Research Articles

Thermophysical properties for the binary mixtures of 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [hmim][Tf2N]+N-methyldiethanolamine (MDEA) at temperatures (303.15 to 323.15) K

Abstract Binary mixtures of 1-hexyl-3-methylimidazolium bis(trisfluoromethylsulfonyl)imide [hmim][Tf 2 N] with N -methyldiethanolamine (MDEA) were prepared. Physical properties namely, density ρ , dynamic viscosity η and refractive index n D , of the binary mixtures were measured over a temperature range of 303.15 K to 323.15 K. Excess molar volumes V E and excess refractive indices n D E were calculated from the experimental values and fitted to the Redlich–Kister equation. Viscosity values of binary mixtures were correlated by McAllister three body interaction model. Excess molar volumes showed positive deviations, whereas excess refractive indices showed negative values over the entire range of concentrations and temperatures. The coefficients of thermal expansion α , and excess coefficients of thermal expansion α E were also calculated from the experimental data.

Densities and refractive indices of the deep eutectic solvents (choline chloride + ethylene glycol or glycerol) and their aqueous mixtures at the temperature ranging from 298.15 to 333.15 K

Deep eutectic solvents (DES) are new emerging alternatives to conventional ionic liquids that may find a number of interesting applications in industrial and chemical processes. In this study, the densities, ρ, and refractive indices, nD, of the DESs (choline chloride+ethylene glycol) and (choline chloride+glycerol) and their aqueous mixtures were investigated at atmospheric pressure over the temperature range 298.15–333.15K and across a complete composition range. The excess molar volumes, VE, and refractive index deviations, ΔnD, were also calculated from experimental results. The calculated excess molar volumes were negative at all temperatures over the entire range of composition considered, suggesting the presence of strong interactions between water and the DES in the mixtures. The refractive index deviations, on the other hand, were found positive in the entire concentration range. The calculated properties were fitted to a Redlich–Kister type equation to correlate them to the temperature and composition. The correlations used satisfactorily represent the densities and refractive indices of the pure DESs and their aqueous binary mixtures as functions of temperature and composition as indicated by the low overall average absolute deviations obtained in the calculations.

Densities, Excess Molar Volumes, Viscosity, and Refractive Indices of Binary Mixtures of Ethanoic Acid and Trichloroethylene with Dimethylbenzenes at Different Temperatures

Liquid densities, ρ, of binary mixtures of ethanoic acid and trichloroethylene with 1,2-dimethylbenzene, 1,3-dimethylbenzene, and 1,4-dimethylbenzene were measured over the entire range of composition at (293.15, 298.15, and 303.15) K and at ambient pressure (81.5 kPa). The excess molar volumes, VmE, for the binary mixtures were calculated. The excess molar volumes of trichloroethylene with dimethylbenzenes are negative over the whole mole fraction range and become more negative with increasing temperature. The VmE values are positive for binary mixtures of ethanoic acid with dimethylbenzenes and become more positive with increasing temperature. Also, the dynamic viscosity, η, and refractive indices, nD, were measured at 298.15 K. The excess molar volume and viscosity were compared with some values of literature at different temperatures and pressures.

Physical and Excess Properties for Binary Systems Containing an Alcohol and Ionic Liquid at T = 298.15K

Abstract In this paper, density, speed of sound and refractive index of six binary systems (alcohol + ionic liquid) were measured, along the whole composition range, at T = 298.15 K and atmospheric pressure. The ionic liquids used in this work are constituted by different cations (pyridinium and pyrrolidinium), anions (trifluoromethanesulfonate and dicyanamide) and alkyl-side chain (propyl- and butyl-). From the experimental data, excess molar volumes, excess molar isentropic compressions and excess refractive index were calculated and satisfactorily fitted using the Redlich-Kister equation. The obtained results show that the physical and excess properties studied in this work are dependent on the structure of the ILs, especially on the anion.

Thermodynamic Properties of Binary Mixtures of the Amino Acid Ionic Liquids [Bmim][Glu] or [Bmim][Gly] with Methanol at T=298.15 to 313.15 K

Densities, viscosities and refractive indices were determined for two ionic liquid mixtures formed by the 1-butyl-3-methylimidazolium glutamic acid salt ([Bmim][Glu]) or the 1-butyl-3-methylimidazolium glycine acid salt ([Bmim][Gly]), respectively, with methanol over the mole fraction from 0.1 to 0.9 and at temperatures ranging from 298.15 K to 313.15 K at intervals of 5 K and at atmospheric pressure. Excess molar volumes, viscosity deviations and refractive index deviations have been calculated from the experimental data and fitted to a Redlich–Kister polynomial function. The results have been interpreted in terms of ion-dipole interactions, and structural factors of the ionic liquid and alcohol molecular liquids.

Density, excess molar volumes and refractive indices of β-pinene with o, m, p-xylene and toluene at 303.15, 308.15 and 313.15 K

Densities (ρ), excess molar volumes (VE ), refractive indices (nD ) and deviation in refractive (ΔnD ) indices on mixing for β-pinene with o-xylene, m-xylene, p-xylene and toluene have been determined at T = 303.15, 308.15 and 313.15 K. The excess molar volume and deviation in refractive index have been fitted to Redlich–Kister polynomials. In addition, deviations in refractive indices were compared with the predictions of several mixing rules. Results obtained have been discussed in terms of intermolecular interactions.

Thermophysical properties of binary mixtures {1-methyl-3-pentylimidazolium tetrafluoroborate + polyethylene glycol methyl ether}

Few reports are available on the thermophysical properties of ionic liquid (IL) and the polymeric (or oligomeric) solution binary system. In this study, the densities, viscosities, and refractive indices were determined for IL mixtures formed by 1-methyl-3-pentylimidazolium tetrafluoroborate [MPI][BF4] with polyethylene glycol methyl ether (MPEG) [Mw=350] over the mole fraction ranging from 0.1 to 0.9 and temperatures from 293.15 to 353.15K at intervals of 5K and atmospheric pressure. The temperature dependence of density and dynamic viscosity for both neat [MPI][BF4] and its binary mixtures were described by an empirical linear equation and by the Vogel–Tammann–Fulcher (VTF) equation, respectively. Excess molar volumes, viscosity deviations, and refractive index deviations were calculated from the experimental data and fitted to a Redlich–Kister polynomial function. The excess molar volume and viscosity deviations for the binary system were negative over both the composition and temperature ranges, whereas the refractive index deviations were always positive. The results have been interpreted in terms of ion–dipole interactions and the structural factors of the IL and MPEG molecular liquids.

Effect of the temperature on the physical properties of pure 1-propyl 3-methylimidazolium bis(trifluoromethylsulfonyl)imide and characterization of its binary mixtures with alcohols

In this paper, physical properties of a high purity sample of the ionic liquid 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [PMim][NTf 2], and its binary mixtures with methanol, ethanol, 1-propanol, and 2-propanol were measured at atmospheric pressure. The temperature dependence of density, refractive index and speed of sound (293.15 to 343.15) K and dynamic viscosity (298.15 to 343.15) K were studied at atmospheric pressure by conventional techniques for the pure ionic liquid. For its mixtures with alcohols, density, speed of sound, and refractive index were measured at T = 298.15 K over the whole composition range. The thermal expansion coefficient of the [PMim][NTf 2] was calculated from the experimental results using an empirical equation, and values of the excess molar volume, excess refractive index, and excess molar isentropic compressibility for the binary systems at the above mentioned temperature, were calculated and fitted to the Redlich–Kister equation. The heat capacity of the pure ionic liquid at T = 298.15 K was determined using DSC.

A Study of Some Physical Properties for Binary System of Cyclohexane with n-decane and 1-pentanol at Different Temperatures

mixtures of cyclohexane + n-decane and cyclohexane + 1-pentanol have been measured at 298.15, 308.15, 318.15, and 328.15 K over the whole mole fraction range. From these results, excess molar volumes, VE , have been calculated and fitted to the Flory equations. The VE values are negative and positive over the whole mole fraction range and at all temperatures. The excess refractive indices nE and excess viscosities ?E have been calculated from experimental refractive indices and viscosity measurements at different temperature and fitted to the mixing rules equations and Heric – Coursey equation respectively to predict theoretical refractive indices, we found good agreement between them for binary mixtures in this study. The variation of these properties with composition and temperatures of the binary mixtures are discussed in terms of molecular interactions.

A Study of Some Physical Properties for Binary System of Cyclohexane with n-decane and 1-pentanol at Different Temperatures

mixtures of cyclohexane + n-decane and cyclohexane + 1-pentanol have been measured at 298.15, 308.15, 318.15, and 328.15 K over the whole mole fraction range. From these results, excess molar volumes, VE , have been calculated and fitted to the Flory equations. The VE values are negative and positive over the whole mole fraction range and at all temperatures. The excess refractive indices nE and excess viscosities ?E have been calculated from experimental refractive indices and viscosity measurements at different temperature and fitted to the mixing rules equations and Heric – Coursey equation respectively to predict theoretical refractive indices, we found good agreement between them for binary mixtures in this study. The variation of these properties with composition and temperatures of the binary mixtures are discussed in terms of molecular interactions.

Densities, Excess Molar Volumes, and Refractive Properties of the Binary Mixtures of the Amino Acid Ionic Liquid [bmim][Gly] with 1-Butanol or Isopropanol at T = (298.15 to 313.15) K

Densities and refractive indices were determined for two ionic liquid (IL) mixtures formed by 1-butyl-3-methylimidazolium glycine acid salt ([bmim][Gly]), with 1-butanol or isopropanol, respectively, over the mole fraction range from (0.1 to 0.9) and at temperatures from (298.15 to 313.15) K at intervals of 5 K and atmospheric pressure. Excess molar volumes and refractive index deviations have been calculated from the experimental data and fitted to a Redlich–Kister polynomial function. The excess volumes for the two systems are negative over both the composition and temperature ranges, whereas the refractive index deviations are always positive. Finally, results have been interpreted in terms of molecular interactions and molecular structures in these binary mixtures.

Densities, Viscosities, and Refractive Properties of the Binary Mixtures of the Amino Acid Ionic Liquid [bmim][Ala] with Methanol or Benzylalcohol at T = (298.15 to 313.15) K

Densities, viscosities, and refractive indices were determined for two ionic liquid (IL) mixtures formed by 1-butyl-3-methylimidazolium alanine acid salt ([bmim][Ala]) with methanol or benzylalcohol, respectively, over the mole fraction range from (0.1 to 0.9) and at temperatures from (298.15 to 313.15) K at intervals of 5 K and atmospheric pressure. Excess molar volumes, viscosity deviations, and refractive index deviations have been calculated from the experimental data and fitted to a Redlich–Kister polynomial function. The results have been interpreted in terms of ion–dipole interactions and structural factors of the IL and alcohol molecular liquids.

Excess molar volumes and refractive indices of binary mixtures of isopropylethanoate and symmetrical hydrocarbons at 308.15 K

AbstractDensities and refractive indices of binary mixtures of isopropylethanoate with several symmetrical hydrocarbons viz cyclohexane, benzene, 1,4‐dimethylbenzene and 1,3,5‐trimethylbenzene at 308.15 K have been measured. The excess molar volumes (VE) are evaluated from the measured density values for the four binary systems. Experimental refractive indices are used to evaluate deviation in refractive indices (Δn) and molar refraction at experimental temperature. VE values are positive for the mixtures studied except binary mixtures between ester and 1,4‐dimethylbenzene which have negative VE values. Standard deviations σ(VE) and σ(Δn) are also reported. Results are discussed in terms of molecular interactions between the components of the mixtures.Nous avons mesuré les densités et les indices de réfraction de mélanges binaires d'isopropyléthanoate avec plusieurs hydrocarbures symétriques, soit du cyclohexane, du benzène, du 1,4‐diméthylbenzène et du 1,3,5‐triméthylbenzène à 308,15 K. Les volumes molaires excédentaires (VE) ont été évalués à partir des densités mesurées pour les quatre systèmes binaires. Les indices expérimentaux de réfraction ont servi à évaluer l'écart des indices de réfraction (Δn) ainsi que la réfraction molaire à la température expérimentale. Les valeurs des VE étaient positives pour les mélanges étudiés à l'exception des mélanges binaires d'ester et de 1,4‐diméthylbenzène qui présentaient des valeurs des VE négatives. Les écarts type σ(VE) et σ(Δn) sont également indiqués. La discussion des résultats porte sur les interactions moléculaires entre les composants des mélanges. © 2010 Canadian Society for Chemical Engineering

<b>Excess molar volumes, and refractive index of binary mixtures of glycerol + methanol and glycerol + water at 298.15 K and 303.15 K</b>

Excess molar volumes (VE) viscosities and refractive index have been evaluated for binary mixtures of glycerol + water, and glycerol + methanol at 298.15 K and 303.15 K. Excess molar volumes (VE) have been calculated from density. The excess molar volume (VE) results were fitted to the Redlich and Kister type polynomial equation to derive the binary coefficients and estimate the standard deviations between experimental and calculated results. It is observed that all mixtures show positive values of VE obviously due to increased physical interactions between glycerol and methanol, and water.KEY WORDS: Excess molar, Density, Refractive index, Glycerol, Water, Methanol Bull. Chem. Soc. Ethiop. 2011, 25(1), 111-118.

Densities, Excess Molar Volumes, Viscosities, and Refractive Indices of Binary Mixtures of n-Butyl Acetate with 1-Chloroalkanes (C4–C8) at 298.15 K

Densities, viscosities, and refractive indices of binary mixtures of n-butyl acetate (1) +1-chlorobutane (2), +1-chloropentane (2), +1-chlorohexane (2), +1-chloroheptane (2), and +1-chlorooctane (2) were measured at 298.15 K for the liquid region and at ambient pressure for the whole composition range. The excess molar volumes VE were calculated from experimental densities. McAllister’s three-body interaction, and Hind and Grunberg–Nissan models are used for correlating the viscosity of binary mixtures. The experimental data of binaries are analyzed to discuss the nature and strength of intermolecular interactions in these mixtures.

Volumetric Properties, Viscosities, and Refractive Indices for Aqueous 1-Amino-2-Propanol (Monoisopropanolamine (MIPA)) Solutions from (298.15 to 343.15) K

Densities and viscosities at six temperatures in the range (298.15 to 343.15) K and refractive indices at nine temperatures in the range (293.15 to 333.15) K are reported for aqueous solutions of 1-amino-2-propanol (monoisopropanolamine (MIPA) or 1-AP). Excess molar volumes, viscosity deviations, and refractive index deviations were calculated from the measurement results and correlated as a function of composition using the Redlich-Kister relation and polynomial equations. Partial molar volumes at infinite dilution were determined from the apparent molar volumes. Negative values for excess molar volumes and molar refraction changes are observed over the whole composition range, whereas viscosity data exhibit both negative and positive deviations. Cross-associated hydrogen bonds forming between 1-AP and water contribute to the deviations in the properties with respect to mole fractions and temperatures.

Refractive Index of Liquid Mixtures: Theory and Experiment

An innovative approach is presented to interpret the refractive index of binary liquid mixtures. The concept of refractive index "before mixing" is introduced and shown to be given by the volume-fraction mixing rule of the pure-component refractive indices (Arago-Biot formula). The refractive index of thermodynamically ideal liquid mixtures is demonstrated to be given by the volume-fraction mixing rule of the pure-component squared refractive indices (Newton formula). This theoretical formulation entails a positive change of refractive index upon ideal mixing, which is interpreted in terms of dissimilar London dispersion forces centred in the dissimilar molecules making up the mixture. For real liquid mixtures, the refractive index of mixing and the excess refractive index are introduced in a thermodynamic manner. Examples of mixtures are cited for which excess refractive indices and excess molar volumes show all of the four possible sign combinations, a fact that jeopardises the finding of a general equation linking these two excess properties. Refractive indices of 69 mixtures of water with the amphiphile (R,S)-1-propoxypropan-2-ol are reported at five temperatures in the range 283-303 K. The ideal and real refractive properties of this binary system are discussed. Pear-shaped plots of excess refractive indices against excess molar volumes show that extreme positive values of excess refractive index occur at a substantially lower mole fraction of the amphiphile than extreme negative values of excess molar volume. Analysis of these plots provides insights into the mixing schemes that occur in different composition segments. A nearly linear variation is found when Balankina's ratios between excess and ideal values of refractive indices are plotted against ratios between excess and ideal values of molar volumes. It is concluded that, when coupled with volumetric properties, the new thermodynamic functions defined for the analysis of refractive indices of liquid mixtures give important complementary information on the mixing process over the whole composition range.

Excess properties of binary mixtures hexane, heptane, octane and nonane with benzene, toluene and ethylbenzene at T = 283.15 and 298.15 K

Densities, speeds of sound and the refractive indices of binary systems containing alkanes (hexane, heptane, octane and nonane) with aromatic compounds (benzene, toluene and ethylbenzene) at T = 283.15 and 298.15 K under atmospheric pressure were determined over the whole composition range. From the experimental results, the derived and excess properties (excess molar volumes, isentropic compressibility, excess molar isentropic compressibility and refractive index deviations) at T = 283.15 and 298.15 K were calculated and satisfactorily fitted to the Redlich–Kister equation.

Densities, Viscosities and Refractive Indices of n- Butanol + Allyl Chloride Mixture at 298K

The density ρ, viscosity η, refractive index n and dielectric constant es of binary mixture of Allyl Chloride (AC) with n-Butanol including those of the pure liquids, were measured over the complete composition range at 298K. The experimental data is used to calculate excess molar volumes (v E ), excess permittivity (es E ), excess viscosity (η E ), excess refractive index, molar refraction, excess molar polarization and Dunstan’s constant. The variations of these parameters with composition and the effect of bonding in the binary mixture are discussed from the point of view of intermolecular interactions in these mixtures. The positive value of excess molar volume (v E ) is attributed to the breaking of H-bonded associated species formed between unlike molecule at 298K.

Densities, Viscosities, and Refractive Indices of Binary Mixtures of Methyl Ethyl Ketone + Pentanol Isomers at Different Temperatures

Densities, viscosities, and refractive indices of mixing of methyl ethyl ketone with 1-pentanol, 2-pentanol, and 3-pentanol have been measured as a function of composition range at temperatures (298.15, 308.15, and 318.15) K and ambient pressure. Excess molar volumes VmE, viscosity deviations Δη, and refractive index deviations ΔnD were calculated and correlated by the Redlich−Kister-type function to derive the coefficients and estimate the standard error. From the experimental data, partial molar volumes, Vm,i, and partial molar volumes at infinite dilution, Vm,i0, were also calculated. The latter values are interesting from a theoretical point of view since at infinite dilution the only interactions present are solute−solvent interactions. The effect of temperature and −OH group position of pentanol isomers on the excess molar volumes, viscosity, and refractive index deviations of its mixtures with methyl ethyl ketone is discussed in terms of the nature and type of intermolecular interactions in binar...