Refractive Index Deviations Research Articles

Viscosity, heat capacity and refractive index studies for binary liquid mixtures containing 1,3-diaminopropane and alkyl acetates: Experimental and theoretical interpretation

The viscosity (η), heat capacity (CP) and refractive index (nD) of 1,3-DAP (1,3-Diaminopropane) (1) + AAc (MAc(methyl acetate), EAc(ethyl acetate), PAc(propyl acetate) and BAc(butyl acetate)) (2) binary mixture were measured at standard ambient temperature i.e. 298.15 K under the atmospheric pressure 0.1 MPa. The data of η, CP and nD were further used to determine deviation in viscosity (Δη), excess molar heat capacity (CPE), excess Gibbs free energy of activation (G∗E), and deviation in refractive index (ΔnD). η were analyzed by Bloomfield and Dewan model (BFD). The η values were further correlated by various correlations like Kendall, Bingham, Kendall-Monroe, Arrhenius, Katti-Chaudhari, Tamura-Kurata, Grunberg-Nissan, Frenkel, Hind-McLaughlin-Ubbelohde, Heric, McAllister, Lulian, Krishnan-Laddha and Heric-Brewer. Further various correlations like Heller, Lorentz-Lorenz, Arago-Biot, Newton, Gladstone-Dale, Erying and Weiner were used to correlate nD data. The derived thermo-physical properties were also interpreted in terms of molecular interactions and correlated with Redlich- Kister polynomial equation (R.K.).

Derivation of acoustical streaming equations for nonlinear and dispersive fluids

The equations of streaming generated by an acoustic mod propagating in a nonlinear dispersive medium (exhibiting absorption and dispersion of phase sound speed) are derived with an arbitrarily shaped incident acoustical field assumed. This field may be periodic or non-periodic. A general dispersion model represented by a convolution operator taking into account relaxation effects was taken into account. Making the assumption of a periodic acoustic field from the general streaming equation.The quasi-stationary flow is driven by a force given by the average value of the dispersion operator with respect to the velocity and acoustic pressure fields. In the spectral representation, it is given by the weighted spectral power density distribution of the acoustic field. The weight of the distribution is the dispersion coefficient - the eigenvalue of the dispersion operator. A new result also reveals the effect of the refractive index deviation on the driving force of streaming. The possibility of generalizing the description of streaming in the simplest case of a non-Newtonian fluid was analyzed. The Reiner-Revlin model of a simple liquid was assumed. It was also noted that the streaming model in the Maxwell liquid is analytically solvable. It was found that asymptotic states of streaming in this model and the Navier-Stokes model are identical.The derivations use new methods different from those used so far. They are based on the separation of nonlinear modes in the momentum transport equation and on the properties of the Gauss-Weierstrass function for the Fick diffusion operator. So far, the method of successive approximations has been used. The consistency of the obtained equations with the assumptions was checked. The obtained formulas generalize the known descriptions of the form of forces driving streaming and extend their application to the case of nonlinear propagation.

Molecular interaction in the binary mixtures of tetrahydrofuran and 1,4-dioxane with methanol. New UNIFAC-VISCO interaction parameters for cyclic ethers

Densities (ρ), viscosities (η), and refractive indices (nD) have been measured for binary organic systems of methanol (MeOH) with tetrahydrofuran (THF) and 1,4-dioxane (DXN) over the entire range of composition, and at different temperatures between 298.15 and 318.15 K. From the data of ρ, η, and nD, properties such as excess molar volume, VmE, thermal expansivity, α, excess thermal expansivity, αE, deviation in viscosity, Δη, free energy for the activation of viscous flow, ΔG≠, and its excess, ΔG≠E, and deviation in refractive index, ΔnD, were derived. Measured ρ, η, and nD were correlated with the concentration-dependent polynomial equations, and their excess properties were fitted with Redlich-Kister type equations. Temperature-dependent Jouyban-Acree model was also used to correlate the experimental ρ and η. Negative values of VmE and Δη, and ΔG≠E lead to reveal that the effect of cross hydrogen bonding plays a significant role in both the systems of THF + MeOH and DXN + MeOH. Finally, six new pairs of group–group interaction parameters, αnm, were determined for these cyclic ethers, which can be utilized in extending further the applicability of UNIFAC-VISCO model.

Density, Speed of Sound, and Refractive Index Data for Oct-1-ene (1) + Propan-1-ol (2)/Propan-2-ol (2) Mixtures at T = (298.15–338.15) K and 0.101 MPa

Density, speed of sound, and refractive index measurements were conducted for the systems oct-1-ene + propan-1-ol/propan-2-ol over the entire composition range at temperatures of T = (298.15, 308.15, 318.15, 328.15, and 338.15) K and at atmospheric pressure, 0.101 MPa. It was discovered that these characteristics showed nonlinear relations with composition, indicating that the mixtures behave nonideally. From the experimental data, derived thermophysical behaviors were obtained by calculation for excess molar volume, deviation in speed of sound, excess isentropic compressibility, deviation in thermal expansivity, and deviation in refractive index. The excess molar volumes were found to be positive over the entire composition range for both systems, with the oct-1-ene + propan-2-ol system exhibiting a larger deviation from ideal volume mixing behavior in comparison to the oct-1-ene + propan-1-ol system. A systematic increasing trend with temperature was observed. The deviation in speed of sound exhibited a nonlinear trend with composition and is positive over the entire composition range. The excess isentropic compressibility exhibited transitional behavior from positive to negative. At temperatures below 328.15 K, a negative deviation in refractive index was observed for both systems for the entire composition range; however, as the temperature increased, a positive deviation is observed in the octene-rich region for the propan-2-ol systems. The excess/deviation properties were correlated by the Redlich–Kister polynomial.

Optical studies of binary mixture containing palm biodiesel and alkanols : experimental and theoretical interpretation

Refractive indices (nD ) of binary mixture containing palm biodiesel (P) and alkanols (1-pentanol (1P) and 3-pentanol (3P)) were measured at different temperatures (298.15,303.15k,308.15k,313.15k,318.15k) at 0.1 MPa over the entire composition range of mole fractions. The nD values of pure compounds and their binary mixtures were measured by using refractometer (Anton Paar Abbemat 200). Experimental data of nD were used to compute deviation in refractive index (Δn). Further, refractive index values also have been measured in terms of different mixing rules like Lorentz-Lorentz (L.L), Gladstone-Dale (G.D), Heller-relation (H.R) and Weiner-relation (W.R). The experimental data of nD compared well with the values obtained by using mixing rules for binary mixture P (1) + Alkanols (2). The measured data were correlated by Redlich-Kister polynomial equation. The effect of temperature has also been investigated.

Thermodynamic study of triacetin or ethyl levulinate and alcohol binary mixtures

The subject of presented research is the study of liquid binary mixtures consisting of ester and alcohol combination; triacetin or ethyl levulinate, as one component, and ethanol or isobutanol, as second component. Thermodynamic and transport data were measured in the broad temperature range, T=(288.15/298.15–323.15/333.15) K, and at atmospheric pressure, p = 0.1 MPa. All corresponding excess and deviation properties were calculated including the excess molar volume, viscosity deviation, refractive index deviation, isentropic compressibility deviation and excess molar Gibbs energy of activation of viscous flow, and correlated with the basic Redlich-Kister equation. The analysis of possible chemical interactions and structural effects taking place in the mixtures was led in the terms of ester structure, complexity of ester molecule and chain length and branching of the alcohol molecule. The thermodynamic analyses showed change of the sign of the excess molar volume depending on the alcohol present in the mixture. FT-IR spectra were recorded for all four systems for the compositions where maximum excess molar volumes are obtained to support the conclusions derived from the mixtures’ nonideal behaviour. In addition, modelling of viscosity is performed with the two- and three-parameter correlative models, as well as excess molar volume correlation with the Peng-Robinson equation of state and three-parameter van der Waals mixing rule.

Optical Tunability and Characterization of Mg-Al, Mg-Ti, and Mg-Ni Alloy Hydrides for Dynamic Color Switching Devices.

Mg shows great potential as a metal hydride for switchable optical response and hydrogen detection due to its ability to stably incorporate significant amounts of hydrogen into its lattice. However, this thermodynamic stability makes hydrogen removal difficult. By alloying Mg with secondary elements, the hydrogenation kinetics can be increased. Here, we report the dynamic optical, loading, and stress properties of three Mg alloy systems (Mg-Al, Mg-Ti, and Mg-Ni) and present several novel phenomena and three distinct device designs that can be achieved with them. We find that these materials all have large deviations in refractive index when exposed to H2 gas, with a wide range of potential properties in the hydride state. The magnitude and sign of the optical property change for each of the alloys are similar, but the differences have dramatic effects on device design. We show that Mg-Ti alloys perform well as both switchable windows and broadband switchable light absorbers, where Mg0.87Ti0.13 and Mg0.85Ti0.15 can achieve a 40% transmission change as a switchable window and a 55% absorption change as a switchable solar absorber. We also show how different alloys can be used for dynamically tunable color filters, where both the reflected and transmitted colors depend on the hydrogenation state. We demonstrate how small changes in the alloy composition (e.g., with Mg-Ni) can lead to dramatically different color responses upon hydrogenation (red-shifting vs blue-shifting of the resonance). Our results establish the potential for these Mg alloys in a variety of applications relating to hydrogen storage, detection, and optical devices, which are necessary for a future hydrogen economy.

Thermophysical modelling of transport and optical properties of 1-propanol+1,3-diaminopropane or 1,2-diaminopropane or 1-amino-2-propanol binary liquid mixture at T=298.15-318.15 K: Molecular interaction analysis by density functional theory (DFT) and graph theoretical approach (GTA)

BackgroundPure liquid properties cannot always satisfy the need of chemical processes. Therefore, liquid mixtures are preferred in different compositions, and the thermo-physical properties of liquid mixtures are highly significant for different processes. The present report involves thermo-physical of amines and 1-propanol. Amines are utilized for CO2 absorption processes. MethodsThe viscosity (η) and refractive index (nD) of 1P (1-propanol) (1) + Amines (1,3-DAP(1,3-diaminopropane), 1,2-DAP(1,2-diaminopropane) and 1A2P(1-amino-2-propanol)) (2) binary mixture were measured at T = 298.15-318.15 K under the atmospheric pressure 0.1 MPa. Experimental data of η and nD were further used to determine deviation in viscosity (Δη), excess Gibbs free energy of activation (G*E) and deviation in refractive index (ΔnD). Δη were analyzed by Bloomfield and Dewan model (BFD) and also examined in term of Graph theoretical approach (GTA). The η and nD data were further correlated by various relevant correlations Significant findingsThe derived thermo-physical properties were well correlated with Redlich-Kister polynomial equation. DFT studies indicated the strength of molecular interactions and supported the graph theory in predicting probable associative molecular species in the liquid mixtures. Further, in 1P + amines binary liquid mixtures, the dominant interaction is OH—–NH.

Thermophysical Properties of Biodiesel with Ethyl Levulinate, Ethyl Acetoacetate, and Ethyl Pyruvate + MgO Mixtures from 288.15 to 338.15 K

Thermophysical properties are important to design the fuel system components and to evaluate new alternative fuels in diesel engine tests. Also, experimental properties allow us to understand the type of interactions present in the studied mixtures. Densities, viscosities, and refractive indices of biodiesel + ethyl levulinate, + ethyl acetoacetate, and + ethyl pyruvate with MgO mixtures have been measured from 288.15 to 338.15 K at 0.1 MPa over the whole composition range and at a constant concentration of 5 × 10–6 in mass fraction for MgO. Our experimental properties for the pure ketoesters agree with data reported in the literature within an average absolute percentage deviation of 0.056, 3.140, and 0.027 % for density, viscosity, and refractive index, respectively. Vibrating tube densimeter, glass capillary viscosimeter, and Abbemat refractometer have been used to measure the properties. Densities and viscosities of the biodiesel mixtures have been compared with the biodiesel fuel standard EN 14214. Flash point, cetane index, and calorific value of the biodiesel mixtures that meet the EN 14214 norm have been measured. Excess molar volume, viscosity deviation, and refractive index deviation are obtained from experimental data and correlated using the Redlich–Kister equation. Equations reported in the literature are used to correlate the thermophysical properties of the investigated mixtures.

Prediction of refractive indices and molecular radii of binary mixtures of Polyethylene glycol (PEG-200,400) and cyclic ethers: Insight into molecular interactions

Using five refractive index mixing rules: Lorentz–Lorenz, Gladstone–Dale, Weiner, Heller, and Arago –Biot; refractive indices of six binary polymer mixtures have been determined at 303.15 K, under atmospheric pressure. The binary mixtures investigated here are PEG-200 + 1,3-Dioxolane, PEG-200 + Oxolane, PEG-200 + Oxane, PEG-400 + 1,3-Dioxolane, PEG-400 + Oxolane, and PEG-400 + Oxane. A good agreement has been observed between the obtained results and respective literature data for all these mixtures. The relative merit of refractive index mixing rules is assessed. Deviation in refractive index and reduced free volume values are also calculated using the refractive index data taken from the literature. Furthermore, the molecular radius of these binary polymer mixtures is computed with the help of the refractive index and molar volume data. In addition, an ideal mixing method is also employed to calculate the molecular radius of these systems.The molecular radius of these binary mixtures is found to be additive with respect to the mole fraction of the pure components. Finally, the results are discussed in terms of the intermolecular interactions among the constituent molecules.

Quasi-Optical Measurement and Complex Refractive Index Extraction of Flat Plate Materials Using Single Time-Domain Transmission Model in Y-Band

Accurate acquisition of the complex refractive index of materials is of great significance to understand their physical properties. Based on a single time-domain transmission model in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Y$ </tex-math></inline-formula> -band, here, we develop a free-space nondestructive testing method combined with parameter extraction of flat plate materials. This method overcomes the limitation of the narrow frequency band of S-parameters of vector network analyzer (VNA), truncates multiple echo interferences in time-domain signals inside sample after the inverse fast Fourier transform (IFFT), and eliminates the crimping effect of the calculation results. In order to ensure the good signal integrity of the model, an empirical formula is proposed to calculate the minimum thickness of the sample corresponding to unit bandwidth. An <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8f$ </tex-math></inline-formula> quasi-optical system is designed and optimized to provide a measuring condition of terahertz (THz) plane wave with high energy density. Compared with the values calculated by the conventional methods, the refractive index deviation is less than 0.004 (0.2%), which verifies the effectiveness and applicability of our proposed method. The adaptability of different processes to the corresponding physical transmission model is further analyzed, and the reasons for the calculation deviation are explained. This work reduces the complexity and difficulty of the material measurement in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Y$ </tex-math></inline-formula> -band, as well as the requirements of system calibration.

Density, viscosity, refractive index and molecular interaction of polyethylene glycol 400 + 1,3-propanediamine deep eutectic solvent for CO2 capture

A new deep eutectic solvent (DES) was obtained using polyethylene glycol 400 (PEG400) as the H bond donor (HBD) and 1,3-propanediamine (PDA) as the H bond acceptor (HBA). Meanwhile, density(ρ), viscosity (η) and refractive index (nD) of (PEG400 + PDA) DES at T = (293.15 to 318.15) K with the step size of 5 K were measured under atmospheric pressure. Through the measured base data, excess molar volume (VmE), excess refractive index (nDE), viscosity deviation (Δη), deviation in molar refraction (ΔRM), refractive index deviation(ΔnD), excess Gibbs energy of activation of viscous flow (ΔG∗E), partial molar volume (V1¯ and V2¯), apparent molar volume (Vφ,1 and Vφ,2), molar isobaric thermal expansion (Ep,m) and thermal expansion coefficient (αρ), were systematically calculated and analyzed, and the Redlich-Kister (R-K) equation was used for fitting VmE, nDE, ΔRM, Δη, ΔnD, and ΔG∗E. In addition, several theoretical mixing rules related to refractive index were evaluated and compared with the experimental data. The results showed that there was a specific intermolecular hydrogen bonding interaction in (PEG400 + PDA) DES, which was systemically discussed on the basis of UV–vis, FLS, FTIR and Raman spectral technologies. At the molar fraction with the strongest intermolecular force, the maximum solubility of CO2 per 1 mol PDA was 0.99 mol CO2 at 150 mL/min CO2 flow rate.

Density, Viscosity, and Refractive Index of a Choline Chloride + d-(−)-Fructose Deep Eutectic Solvent + Water Mixture at Different Temperatures: An Experimental Study and Thermodynamic Modeling

In the present study, first, the deep eutectic solvent (DES) of choline chloride + d-(−)-fructose was prepared using the heating method. Then, its physical properties including density, viscosity, and refractive index were experimentally measured at temperatures in the range of 283.15–343.15 K and a full composition range of DES at atmospheric pressure (83.09 kPa). The values of these three properties decrease with an increase in temperature, while the mole fraction has a nonlinear effect on these properties. For the density and refractive index, an increase in the mole fraction of DES to 0.3 causes a sharp increase in these physical properties, while from 0.3 to 1, this increase occurs slowly. For viscosity, increasing the mole fraction of DES has little effect at first, but at high mole fractions of DES, a sharp increase in viscosity occurs. In addition, the sharp change in the viscosity of DES depends on the temperature so that at low temperatures, this phenomenon occurs faster. So, adding water to DES will tailor the viscosity of the mixture to facilitate its applications. A polynomial equation was used to describe the density and refractive index as a function of temperature and mole fraction. Experimental viscosity was fitted to the Vogel–Tammann–Fulcher (VTF) equation. Using the measured data, in sequence, the values of excess molar volume (VmEx), viscosity deviation (Δη), and refractive index deviation (ΔnD) were calculated. The Redlich–Kister polynomial equation, finally, was used to correlate the values of VmEx, Δη, and ΔnD.

Synthetic aperture rainbow refractometry for droplet refractive index and size measurement with long range: Standard and global modes

• Synthetic aperture rainbow refractometry for long distance droplet measurement. • SASRR measures mono-dispersed droplets at 1650 mm distance. • SAGRR measures refractive index and size of spray with high accuracy. Optical characterizations of droplets and sprays at a long stand-off distance are of great demand in large scale facilities. Synthetic aperture rainbow refractometry (SARR) is proposed for long range measurement. The aperture of the imaging system is enlarged via synthesizing rainbow signals of the same droplet illuminated by multiple crossing laser beams from different channels of a color image simultaneously. The formation of the synthetic aperture rainbow signal is modeled by taking spectral response into account, and the retrievals of true rainbow signals are proposed. Both synthetic aperture standard rainbow refractometry (SASRR) and synthetic aperture global rainbow refractometry (SAGRR) are investigated, with corresponding inversion algorithms, and then validated with simulations and experiments. The uncertainties of refractive index and size of mono-dispersed droplet measured with the SASRR are 8 × 10 - 4 and 3 μ m at 1650 mm distance, and for sprays measured with the SAGRR the deviation of refractive index is 8 × 10 - 4 . The proposed synthetic aperture rainbow refractometry enables transparent and spherical droplets and sprays measurement at long distance, and have great potential for large scale industrial applications.

Volumetric, Optical, and Spectroscopic Study of Molecular Interactions for Binary Liquid Mixtures of Gamma-Valerolactone with 2-Alkoxyethanols

Physical parameters such as densities, ρ, and refractive indices, nD, of pure gamma-valerolactone/2-alkoxyethanols and their binaries have been determined over the whole composition range at different temperatures (298.15, 303.15, 308.15, and 313.15 K) and pressure = 0.1 MPa. From the experimental results, excess properties such as excess molar volumes, VmE, deviations in refractive indices, ΔϕnD, and deviations in molar refractions, ΔϕRM, have been calculated. The predicted data were fitted to the Redlich–Kister-type polynomial equation to derive the binary interaction parameters and recognize standard deviations between experimental and calculated values of the liquid solutions. Furthermore, the partial molar volumes, V¯m,1, V¯m,2, and excess partial molar volumes, V¯m,1E, V¯m,2E, were also computed. The Prigogine–Flory–Patterson theory and Graph theory were employed to correlate experimental VmE values. The departure of real mixtures from ideal behavior was interpreted in terms of strength and nature of molecular interactions. Furthermore, Fourier-transform infrared spectroscopy studies of the investigated solution along with pure components were also reported to obtain a better insight into intermolecular interactions between unlike molecules. In our study, positive values of VmE and negative values of ΔϕnD were observed, which suggests weak dispersion forces between dissimilar molecules.

Insight into molecular interactions and structural changes of ethyl lactate and (tri/tetra)-ethylene glycol binary mixture: A thermophysical and spectral depiction

The current work deals with the analysis of the molecular interactions amongst the binary systems formed by significant solvents with environment friendly characteristics. The density (ρ) and refractive index (nD) of pure liquids and mixtures containing L-Ethyl Lactate (EL) + Tri-Ethylene Glycol (TrEG) or Tetra-Ethylene Glycol (TeEG) over the entire composition have been measured at four equidistant temperatures from T/(K) = 298.15 to 313.15 and pressure p/(MPa) = 0.1. Based on the experimental data, calculation of derived properties (excess molar volumes (VmE), partial molar volumes (V¯m), excess partial molar volumes (V¯mE), deviations in refractive index (ΔϕnD) and deviations in molar refraction (ΔϕRM)) was done. The consequent properties were fitted to the Redlich-Kister polynomial equation to recognize the interaction coefficients and standard deviations. The obtained outcomes were examined theoretically through Prigogine-Flory-Patterson (PFP) theory and Graph theory to elucidate the non-ideal behaviour of investigated mixtures. The theoretical interpretations were found to be in harmony with experimental observations. Spectroscopic data from UltraViolet (UV) and Fourier Transform InfraRed (FT-IR) analysis ascertains the dominance of solute-solvent interactions in mixed state hereby supporting the experimental and theoretical analysis.

Thermophysical and excess properties of diesel + biodiesel with octanol isomers at different temperatures

Thermophysical properties of biodiesel mixtures are essential to design the injection system components and evaluate the spray characteristic through the combustion chamber as well as understand the type of interactions present in the mixture. In this work, densities, viscosities, and refractive indices of pseudo-ternary mixtures of diesel + biodiesel + 1-octanol, 2-octanol, and 2-ethyl-1-hexanol have been measured from (288.15 to 338.15) K at 0.1 MPa. In addition, properties of the pseudo-binary mixtures of biodiesel + octanol isomers are reported at the same temperature conditions and over the entire range of compositions. The experimental results for the pure components show agreement with data reported in literature within an average absolute percentage deviation of (0.019, 0.742, and 0.155) % for density, viscosity, and refractive index, respectively. Densities and viscosities of the mixtures have been compared with the limits set by the diesel fuel standard (EN 590). This work presents mixtures that meet these limits and can be considered as alternative fuels to conventional diesel. Excess molar volumes, viscosity deviations, and refractive index deviations are calculated from experimental data and represented through the Redlich-Kister equation. The McAllister and Nava-Ríos et al. equations have been used to correlate the kinematic viscosities of the pseudo binary and ternary mixtures as a function of the molar composition.

Nonlinear optical studies of the temperature evolution of local asymmetric regions in solid solutions (1-x) PbMg1/3Nb2/3O3-xPbSc1/2Nb1/2O3

The temperature dependencies of second harmonic generation (SHG) in (1-x)PMN–xPSN solid solutions (x = 1, 0.35, 0.23, 0.1, 0) are measured. Presence of SHG signal in centrosymmetric phase in all samples studied is demonstrated. It indicates asymmetric regions in the centrosymmetric phase. In PMN crystal (x = 0) in the centrosymmetric phase, SHG temperature dependence follows deviations of strain and refractive index from their high-temperature dependencies, which are determined by random electric fields in local polar regions. In the intermediate temperature range, where macroscopic spontaneous polarization disappears, SHG signal is caused by relatively large and long-lived polar asymmetric regions.

A study on mixing properties of binary mixtures of 1-hexene with alkoxyethanols at different temperatures

Blends of 1-hexene with alkoxyethanols have been studied in terms of intermolecular interactions. The investigated alkoxyethanols were 2-methoxyethanol or 2-ethoxyethanol or 2-butoxyethanol. This study was based on measurements of densities, ρ, speeds of sound, u, and refractive indices, nD, throughout the full range of composition. With the help of measured data, some derived/excess properties have been computed such as excess molar volume, VmE, isentropic compressibility,κs, deviation in isentropic compressibility, Δκs, and deviation in refractive indices, ΔnD and these properties were fitted to a Redlich−Kister equation. Furthermore, PC-SAFT equation of state (PC-SAFT EoS) were used to correctly modeled the density of pure fluids and mixtures whereas the Nomoto’s relation modeled the speed of sound for the binary mixtures with the least deviation, while for the refractive index of all the mixtures, Laplace mixing rule was the best approach..

Thermodynamic study of binary mixtures of 2-propanol with ionic liquids, 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate and triethylhexylammonium bis(trifluoromethylsulfonyl)imide

In this work, densities, speeds of sound, refractive indices and viscosities of three binary mixtures containing the ionic liquids 1-hexyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl)imide, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate and triethylhexyl-ammonium bis(trifluoromethylsulfonyl)imide, mixed with 2-propanol at wide temperature and composition ranges at atmospheric pressure have been measured. From these experimental data, the excess molar volume, excess molar compressibility, deviation in refractive index and deviation in viscosity have been calculated. Excess properties have been correlated with the composition data using Redlich-Kister polynomial equation. The effects of temperature, cation and anion of ionic liquid on the physicochemical properties were analysed and discussed in terms of intermolecular interactions occurring in the studied systems. The Prigogine-Flory-Patterson theory was examined for suitability for the correlation of excess molar volumes with compositions.