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[Display omitted] • The study reports densities of binary mixtures of [BMIM][PF 6 ] + alkyl acetate. • The study reports speeds of sound of [BMIM][PF 6 ] + alkyl acetate binary mixtures. • Provides estimation of excess properties of [Bmim][PF 6 ] + alkyl acetate mixtures. • Study correlates physicochemical properties with interactions in these mixtures. • The FT-IR spectra of equimolar mixture is recorded and correlated with interactions. The purpose of this work is to investigate the influence of concentration, temperature and molecular size on intermolecular interactions in the mixtures of 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6 ] with some alkyl acetates. The densities, ρ and speeds of sound, u for the 1-butyl-3-methylimidazolium hexafluorophosphate + ethyl acetate/propyl acetate/ n -butyl acetate binary mixtures were measured over the entire range of composition at the temperatures, T = (293.15 – 323.15) K at 5 K intervals and at pressure, p = 101 kPa. The experimental data was used to calculate various excess properties, viz. , excess molar volume, excess isentropic compressibility, excess intermolecular free length, excess speed of sound, excess molar isentropic compressibility and excess acoustic impedance. The partial molar volumes and compressibilities; and excess partial molar volumes and compressibilities of the components over the entire composition range and at infinite dilution have also been calculated. The results clearly indicated the presence of intermolecular interactions in these mixtures and the magnitude of [BMIM][PF 6 ]-alkyl acetate interactions followed the order: ethyl acetate > propyl acetate > n -butyl acetate, i.e. , the interactions were found dependent on the size of alkyl group of acetates. The speeds of sound were estimated theoretically using scaled particle theory and compared with experimental findings. FT-IR spectra of pure [BMIM][PF 6 ], ethyl acetate, propyl acetate. n -butyl acetate and their equimolar mixtures were also recorded and analysed for better understanding of prevailing intermolecular interaction. [ABSTRACT FROM AUTHOR]

• Experimental densities and viscosities for binary mixtures were measured. • CPA model was applied to calculate the density of components in mixtures. • Governing molecular interactions were discussed. This paper presents an investigation into the thermodynamic and transport characteristics of 2-methyl-1-butanol and C 7 -C 10 normal alcohols (1-heptanol to 1-decanol), with a specific focus on their binary mixtures. The experimental analysis encompassed a temperature range of 293.15 to 323.15 K, during which the density and viscosity of these mixtures were measured. The study reveals that all the binary mixtures exhibit positive excess molar volumes, which progressively increase as the alkyl chain length in the alcohols increases. Simultaneously, the observed viscosity deviations consistently display negative values across all the mixtures, becoming more pronounced as the alkyl chain lengthens. This behavior of the mixtures highlights the weak molecular interactions between 2-methyl-1-butanol and alcohols. In conjunction with the experimental work, this study utilizes the Cubic-Plus-Association (CPA) model to establish a correlation between the densities of these binary mixtures. The model demonstrates a satisfactory agreement with the experimental densities, signifying its efficacy in correlating the density behavior of such mixtures. The largest discrepancy between the experimental data and the correlated values from the CPA model was observed in the mixture of 2-methyl-1-butanol with 1-heptanol, amounting to a mere 0.29 %. This minor deviation underscores the correlation of the CPA model in reproducing experimental results. [ABSTRACT FROM AUTHOR]

• The thermophysical properties of 2-Methoxyethanol/2-Ethoxyethanol + 1,2-Propanediol were studied. • Investigated composition-temperature-dependent molecular interactions in the binary mixtures. • Applied the Redlich-Kister correlation to model the excess volume and the deviation in viscosity. • Performed theoretical derivation of mixture properties using correlative approaches. In the present investigation density, speed of sound, and viscosity have been reported for binary liquid mixtures of 1,2-propanediol (1,2-PD) with 2-methoxyethanol (2-ME) and 2-ethoxyethanol (2-EE) over the entire composition range at T= (298.15–323.15) K. From the experimental data, excess molar volume, (V m E), excess isentropic compressibility, (κ s E), excess molar isentropic compressibility, (κ s , m E), excess speed of sound, (u E), excess isobaric thermal expansion, α p E , and deviation in viscosity (Δ η) of liquid mixtures have been calculated. The excess partial molar volume, V ¯ m , 1 E , V ¯ m , 2 E , excess partial molar isentropic compressibility, K ¯ s , m , 1 E K ¯ s , m , 2 E over the whole composition range together with partial molar volume, V ¯ m , 1 0 , V ¯ m , 2 0 , partial molar isentropic compressibility K ¯ s , m , 1 0 , K ¯ s , m , 2 0 , excess partial molar volume, V ¯ m , 1 0 E , V ¯ m , 2 0 E and excess partial molar isentropic compressibility, K ¯ s , m , 1 0 E , K ¯ s , m , 2 0 E at infinite dilution have also been calculated. All excess properties have been correlated using the Redlich-Kister smoothing polynomial equation. The V m E results are analysed in the light of Prigogine-Flory-Patterson theory. Analysis of each of the three contributions viz. interactional, free volume, and P* to V m E has shown that interactional contribution and free volume effect are negative for all the mixtures, and P* contribution is positive for the mixtures of 2-ME. The variations of these parameters with changes in composition and temperature have been discussed in terms of intermolecular interactions prevailing in these mixtures. Further, the viscosities of these binary mixtures were correlated theoretically by using various empirical and semi-empirical models and the results were compared with the experimental findings. [ABSTRACT FROM AUTHOR]

• Densities, speed of sound and refractive index were measured for binary mixtures. • All experiments were done in the temperatures range of (298.15–318.15) K. • The excess molar volumes, deviation in isentropic compressibility and refractive index were obtained. • Derived properties were correlated by Redlich–Kister polynomial equation. • The PFP and ERAS models were applied to correlate the excess molar volume. Thermodynamic properties like excess volume V m E , excess partial volume V ¯ m , i E , in isentropic compressibility deviations Δ K s , and refractive index deviations Δ n D , have been calculated based on experimental density ρ , speed of sound u , and refractive index n D , by an Anton Paar / DSA 5000/ densimeter and Anton Paar Abbemat / 500/ refractometer. The systems of diethylene glycol monoethyl ether (DEGEE) + 2-propanol, or + 2-butanol, or + 2-pentanol, or + 2-hexanol, or + 2-heptanol, were given at T = (298.15–318.15) in 10 K intervals at ambient pressure (81.5 kPa) have been investigated. Data was fitted by Redlich-Kister relation. T h e V m E is negative for + 2-propanol and positive sign for other systems observed. The Δ K s is negative for all systems, except for + 2-heptanol system is positive. The Δ n D is negative for + 2-hexanol or + 2-heptanol systems and is positive for all the rest. The The intermolecular interactions and structure factors were discussed for the binary mixtures. In addition the Prigogine–Flory–Patterson theory (PFP) and Extended Real Associated Solutions (ERAS) models were used to correlate V m E data of binary mixtures. The fitting data for all systems reasonable consistency with experimental data for all the systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Reported ρ and u of ethyl acetate + polyethylene glycol (PEG) mixtures. • Study reports calculated values of the excess properties of ethyl acetate + PEGs mixtures. • Correlates excess properties with prevailing interactions in these ethyl acetate + PEGs mixtures. • The ethyl acetate-PEGs interactions follow order: PEG 600 > PEG 400 > PEG 300 > PEG 200. • The FT-IR spectra of equimolar mixtures was recorded and correlated with interactions. The intermolecular interactions in ethyl acetate + polyethylene glycols (PEG) mixtures were examined by means of the excess and partial molar properties and FTIR spectra. The measurements of density and speed of sound of ethyl acetate + polyethylene glycols (PEG 200, PEG 300, PEG 400 and PEG 600) binary mixtures have been carried out over whole composition range at temperature from 293.15 K to 323.15 K and pressure, p = 100 kPa. The ρ and u data have been used to calculate excess properties, viz. , excess molar volume, excess isentropic compressibility, excess intermolecular free length, excess speed of sound and excess molar isentropic compressibility. In addition, the partial molar volume/compressibility; excess partial molar volume/compressibility of the components over the entire composition range, and at infinite dilution have also been calculated. The variations in these properties with composition and temperature have been conversed in terms of existing intermolecular interactions in these mixtures. The ethyl acetate-PEG interactions in these mixtures follow the order: PEG 600 > PEG 400 > PEG 300 > PEG 200. The speeds of sound were estimated theoretically by using the scaled particle theory and were compared with the experimental values. Furthermore, FT-IR spectra of pure ethyl acetate, PEG 200 and their equimolar mixture were also recorded and analysed to confirm the prevailing intermolecular interactions. [ABSTRACT FROM AUTHOR]

• Densities and refractive indices were measured for the binary mixtures of But. isomers (1) + DEP (2) at (293.15–313.15) K temperature range. • Excess molar volumes and excess refractive indices for these binary mixtures were calculated. • Apparent, partial, and excess partial molar volumes were evaluated. • Refractive indices were predicted using several mixing rules. • Results were discussed in terms of molecular interactions. The density (ρ), and refractive index (n D) of three binary mixtures containing 1-butanol, 2-butanol, and 2-methyl-2-propanol with diethyl phthalate (DEP) were studied over the whole range of composition at different temperatures from 293.15 to 313.15 K, and atmospheric pressure (0.082 MPa). Experimental data were used to calculate the excess molar volumes (V m E) and deviation in refractive indices (Δ n D). The experimental density values were used to calculate the partial molar volumes ( V ¯ m , i ), apparent molar volumes (V ∅ , i ), partial molar volumes at infinite dilution ( V ¯ m , i ∞), and excess partial molar volumes ( V ¯ m , i E). A Redlich-Kister type polynomial equation is used with the method of least-squares to set up a correlation between excess molar volumes and deviation in refractive indices, leading to the estimation of binary coefficients and standard errors. Theoretical refractive index values were calculated using seven relations, namely Arago–Biot (A–B), Dale–Gladstone (D–G), Lorentz–Lorenz (L–L), Heller (H), Weiner (W), Newton (Nw) and Eyring and John (E-J). This study examines how composition and temperature affect the variation of parameters in these mixtures, considering molecular interactions. Experimental data and results provide useful information for further thermodynamic studies of alcohol-ester mixtures. [ABSTRACT FROM AUTHOR]

• Density and viscosity of two trifluoromethanesulfonate-based ionic liquids: 1-ethylimidazolium trifluoromethanesulfonate, [Eim][Triflate], and 1-ethylpyridinium trifluoromethanesulfonate, [Epy][Triflate], as well as binary mixtures of these ILs with water or ethanol were measured within the temperature range of 293.15–333.15 K. In the open literature, only the data for the binary system water – [Epy][Triflate] are available. Measured data were evaluated using the Redlich-Kister and Jouyban-Acree correlations, respectively. • Experimental vapor–liquid equilibrium data for binary systems of ethanol or water with both ionic liquids were measured at atmospheric pressure within a broad region of IL concentrations, IL mole fraction ranging between 0 and 0.7 or even 0.8. To the best of our knowledge, the experimental data were presented for the first time. The NRTL model was use in the correlation of experimental data. Density and viscosity of two trifluoromethanesulfonate-based ionic liquids: 1-ethylimidazolium trifluoromethanesulfonate, [Eim][Triflate], and 1-ethylpyridinium trifluoromethanesulfonate, [Epy][Triflate], as well as binary mixtures of these ILs with water or ethanol were measured within the temperature range of 293.15–333.15 K. Measured density data were used to calculate the excess molar volume and the component partial molar volume and the obtained values were fitted using the Redlich-Kister expansion. Variation of viscosity with the binary mixture composition and temperature was modeled using the Jouyban-Acree model. Data on the vapor−liquid equilibrium (VLE) of the respective ionic liquids with water and ethanol were estimated at atmospheric pressure over a wide range of IL concentrations (up to 70 mol% of IL). For the boiling point temperature measurement of four respective binaries, an adapted Siwoloboff procedure was used. To describe VLE of these binary mixtures, ideal vapor phase and real liquid phase behavior were assumed; experimental isobaric t – x data were correlated with the NRTL model. [ABSTRACT FROM AUTHOR]

[Display omitted] • The study reports ρ and u of polyethylene glycol 200 + methyl/ethyl methacrylate mixtures. • Provides estimation of excess properties of PEG 200 + methyl/ethyl methacrylate mixtures. • Study correlates physicochemical properties with interactions in these mixtures. • The scaled particle theory (SPT) is used to predict speed of sound values. • The FT-IR spectra of equimolar mixture is recorded and correlated with interactions. The excess and partial molar properties of binary liquid mixtures can be used to unveil the prevailing intermolecular interactions. The densities, ρ and speeds of sound, u for pure polyethylene glycol 200 (PEG 200), methyl methacrylate, ethyl methacrylate and their binaries (PEG 200 + methyl/ethyl methacrylate) have been measured over the entire composition range in the temperature range (293.15 to 323.15) K at 5 K intervals and at pressure, p = 100 kPa. The excess molar volume, excess isentropic compressibility, excess speed of sound, excess intermolecular free length, excess molar isentropic compressibility and excess acoustic impedance were evaluated using the experimental data. The partial and excess partial molar volumes/compressibilities of the components at each mole fraction and at infinite dilution have also been calculated. The results have been interpreted on the basis of prevailing intermolecular interactions as well as structural effects between like and unlike molecules. The results indicate the effect of the size of alkyl group on excess functions and interactions in these systems and the PEG-methacrylate interactions follow the order: methyl methacrylate > ethyl methacrylate. Scaled particle theory has also been used for the theoretical estimation of the speeds of sound and compared with experimental values. FT-IR spectra of pure PEG 200, methyl methacrylate, ethyl methacrylate and equimolar PEG 200 + methyl methacrylate/ethyl methacrylate mixtures were also recorded and analysed for better understanding of prevailing intermolecular interaction. [ABSTRACT FROM AUTHOR]

• Densities and excess volumes for 2-methoxyethanol + ethylenediamine binary system. • Viscosities and viscosity deviation for 2-methoxyethanol + ethylenediamine binary system. • Form of HBs as –OH⋯NH 2 – in 2-methoxyethanol + ethylenediamine binary system. • 0.6554 mol CO 2 absorbed in binary system at 150 mL/min flow rate and room temperature. To examine the fundamental physicochemical properties as well as intermolecular interactions for the 2-methoxyethanol (EGME) (1) + ethylenediamine (EDA) (2) binary system, this work systemically measured the density (ρ) and viscosity (η) values of the binary system with various mole ratios at P = 100.5 kPa and T = (298.15–318.15) K with the growth gap of 5 K. The as-measured values of the pure substances were compared with literature data. Multiple semi-empirical formulas were used to fit ρ and η values, and the absolute average deviations (AAD%) were calculated. After that, the excess molar volume (V m E), partial molar volume ( V ¯ ), apparent molar volume (V φ), viscosity deviation (Δ Î·), excess activation of Gibbs free energy (Δ G ∗ E ), and several thermodynamic properties of the binary system were systemically analyzed. According to analysis results, it has been proven that the interaction exists between EGME and EDA molecules. And then, excess properties were fitted to the Redlich-Kister equation using multi-parametric nonlinear regression analyses, and standard deviations (σ) were calculated. In addition, based on various characterization methods including Raman, ultraviolet (UV), and nuclear magnetic resonance hydrogen (1H NMR) spectral analyses and density functional theory (DFT) calculation results, it is demonstrated that there is intermolecular hydrogen bonds in EGME (1) + EDA (2) binary system as the form of –OH⋯NH 2 –, which was consistent with the existence forms of intermolecular hydrogen bonds in different alcohol-amine systems from references. Finally, CO 2 absorption capacity by pure EDA, pure EGME, and the EGME (1) + EDA (2) binary system were severally determined. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three hydrophobic DESs composed of TBAB and carboxylic acid were prepared. • Hydrogen bonds' intensity in mixtures was obtained. • Densities and viscosities of the mixtures were measured. • The relationship between the intensity and the properties was established. Deep eutectic solvent (DES) shows excellent absorption performance in the field of CO 2 capture. It is considered as a new green absorption solvent to replace monoethanolamine. In the industry, the presence of water not only affects the structural stability of the solvent, but also affects its thermophysical properties. In this work, three kinds of hydrophobic DES were prepared. Based on the study of their structural characteristics and thermal stability, the density and viscosity of DES with water mixture were measured in the temperature range of 298.15 ∼ 338.15 K at atmospheric pressure. It was demonstrated that the trace water did not destroy the structure of DES, but it formed hydrogen bonds with DES. The increase water destroyed the structure of DES and formed hydrogen bonds with hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA), respectively. Moreover, the hard sphere model was applied to study the viscosity, and after introducing the binary interaction parameter, the average absolute relative deviation of the mixture reduced to 4.4 ∼ 7.7 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • New high-pressure density data for three iodide anion-based ionic liquids. • Alkyl chain length affects ionic liquids' structural packing efficiency. • Intermolecular forces interactions provoke a crossing point in internal pressure. • Four group contribution estimation methods were used for density estimation. Ionic liquids (ILs) constitute a captivating class of materials that has garnered significant attention from research and industrial applications, being recognized as promising substitutes for organic solvents in industrial processes. Consequently, comprehensive experimental physicochemical characterization, explicitly focusing on density data complemented by computational tools, is imperative. In pursuit of this objective, the present study explores the density behavior, both experimentally and computationally, of three iodide-based ionic liquids under high-pressure and high-temperature (HPHT) conditions. Here, it was studied the alkyl chain impact on density for 1-propyl-3-methylimidazolium iodide ([C 3 C 1 Im][I]), 1-butyl-3-methylimidazolium iodide ([C 4 C 1 Im][I]), and 1-hexyl-3-methylimidazolium iodide ([C 6 C 1 Im][I]) ILs. The vibrating tube method was utilized to determine the density over a range of pressure (P = 0.20 to 100.00 MPa) and temperature (T = 298.15 to 398.15 K). The density of the ionic liquids (ILs) was found to be influenced by the length of the cation alkyl chain, exhibiting the following sequence of increasing density: [C 6 C 1 Im][I] < [C 4 C 1 Im][I] < [C 3 C 1 Im][I]. Tammann-Tait equation was used to correlate experimental density data, resulting in an average absolute relative deviation (% A A R D) less than 0.008 % for [C 6 C 1 Im][I] and [C 4 C 1 Im][I], and less than 0.025 % for [C 3 C 1 Im][I]. The ILs density values were used to determine the isothermal compressibility (κ T), the isobaric expansivity (α p), the thermal pressure coefficient (γ v) , and the internal pressure (P i). These results revealed the structural impact of the alkyl chain on packing efficiency and its relationship with its physicochemical properties. Furthermore, ionic liquid density was estimated by using four group contribution estimation methods. Among these methods, the one proposed by Paduszynski and Domanska provided the best density estimative with a maximum % A A R D of 1.09 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mixtures denote strong interactions between unlike species. • Speed of sound deviations are positive and negative for Glyceline + 1-Propanol. • Mixtures show H-bonding between Glyceline and 1-Alcohols. • Glyceline + 1-Butanol exhibits a liquid phase separation. In this work, we present experimental densities, viscosities, and speed of sound of a Deep Eutectic Solvent (Glyceline) with 1-alcohols (C 2 -C 4) from (288.15 to 343.15) K at 0.1 MPa. Densities and speed of sound are from a vibrating tube densimeter while dynamic viscosities are from a rolling ball microviscosimeter. The binary mixture of Glyceline + 1-Butanol presents a liquid–liquid separation. Excess molar volumes, viscosity deviations, speed of sound deviations and isentropic compressibility deviations are calculated from experimental measurements. Excess molar volumes and viscosity deviations are negative at all temperatures. Speed of sound deviations are negative and positive. The Redlich-Kister equation is used to correlate the excess molar volume and the viscosity, speed of sound and isentropic compressibility deviations. We have used the Akaike Information Criterion corrected for small samples to obtain the optimal number of coefficients in the Redlich-Kister equation. Kinematic viscosities are correlated using the McAllister and the Nava-Rios equations. The average absolute percentage deviation of the McAllister equation is 3.09 % while for the Nava-Rios equation is 1.82 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • Liquid to solid phase transition of biodiesel was detected via vibrating tube densimeter technique for the first time. • The established procedure for solidification detection could be extended for other amorphous materials. • Solidification of biodiesel was detected by upwards pressurization. • Liquid densities for waste beef tallow FAMEs, FAEEs and FABEs are reported from 286 to 393 K, and pressures up to 137 MPa. • FAMEs had the highest density, while the lowest density was observed for FABEs. Phase behavior and thermophysical properties of biodiesel at high pressure and high temperature are limited in the literature. These are useful to develop models and to understand their behavior having in mind the use of biodiesel in engines. Liquid to solid phase transitions, by using a vibrating tube densimeter, along with densities of three beef tallow fatty acid alkyl esters were studied in this work. Measurements of the oscillating period for each biofuel were carried out in a modular array constituted by two vibrating tube densimeters coupled in series and connected to a single loading cell. The oscillating period was converted to density by the forced path mechanical calibration (FPMC) method. Experimental liquid density sets for three beef tallow biodiesel samples based on fatty acid alkyl esters (FAAEs) are reported for the first time for pressures up to 137 MPa. These biofuels, named fatty acid methyl esters (FAMEs), fatty acid ethyl esters (FAEEs) and fatty acid butyl esters (FABEs), were measured in the temperature range of 286–393 K. The detection procedure for the beginning of the high-pressure solidification was focused on the beef tallow FABEs sample based upon its lower cloud point (CP FABEs = 281.15 K) in comparison with the reported property for the other esters (CP FAEEs = 289.15 K, CP FAMEs = 291 K) with the same feedstock; therefore, the conditions for the metastable liquid to solid phase transition associated to the effect of high pressure was detailed for waste beef tallow butyl ester biodiesel by performing step-by-step compressions in the interval of 286.20–298.13 K and with the help of the vibrating tube densimeters. FABEs had the lower density in contrast with FAEEs and FAMEs, this one being the denser biofuel. Modeling of liquid density data was performed by the perturbed-chain statistical associating fluid theory (PC-SAFT) Equation of State and the Tammann-Tait equation with maximum absolute average deviations of 0.15 % and 0.05 %, respectively. Both models were applied for correlating the thermodynamic derived properties of the fluid phase: isobaric thermal expansivity and isothermal compressibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • Compressed liquid densities (ρ) of thiophene + heptane, thiophene + octane at high pressures. • Comparison between three different VTD calibration methods (classical using nitrogen and water as references, hexane and water as references, or water and applying vacuum to the VTD). • Representation of the thiophene + heptane and thiophene + octane mixtures density data at different compositions through an empirical model. • Derived properties from density data of the thiophene + heptane and thiophene + octane mixtures at different compositions. New compressed liquid densities (ρ) of thiophene + heptane and thiophene + octane are reported in the temperature range from (313 to 363) K, with pressure up to 25 MPa. The compositions are x(1) = 0.1049, 0.2471, 0.5097, 0.7494, and 0.8994 for thiophene (1) + heptane (2), and x(1) = 0.1042, 0.2530, 0.5037, 0.7516, and 0.8988 for thiophene (1) + octane (2). The experimental system uses a vibrating tube densimeter (VTD) and three calibration methods (the first uses hexane and water, the second uses nitrogen and water, and the third uses water and applying vacuum to the VTD as calibration reference fluids). The reported density data are determined using the third method, which notifies the lowest uncertainty and estimates a maximum relative expanded uncertainty (k = 2) of 0.21 % in the temperature range from (313 to 363) K and pressures up to 25 MPa. The pure compound densities were calculated from previous density measurements represented by the Pimentel-Galicia model. This empirical correlation of the pure compounds was used before for the excess molar volume calculation. The experimental data of the mixtures reported in this work were modeled by the Pimentel-Galicia model at each composition with deviations not higher than 0.07 %. The combined standard uncertainty for composition (considering the purities of the samples) is u c x = 0.0026. Finally, the isothermal compressibility and isobaric thermal expansivity were evaluated from density data. [ABSTRACT FROM AUTHOR]

• Phosphonium-based ionic liquids containing TFSA anion were synthesized by introducing an ether group into the cation. • The density, viscosity, and CO 2 solubility of the ether-functionalized phosphonium-based ionic liquids were measured. • The molality of CO 2 in ether-functionalized phosphonium-based ionic liquids was investigated. • The obtained CO 2 solubility data were correlated using the Peng-Robinson equation of state. • The obtained CO 2 solubility data were thermodynamically investigated. We measured the densities and viscosities of two ionic liquids, triethyl(methoxymethyl)phosphonium bis(trifluoromethanesulfonyl)amide ([P 222(1O1) ][TFSA]) and triethyl(2-methoxyethyl)phosphonium bis(trifluoromethanesulfonyl)amide ([P 222(2O1) ][TFSA]), at atmospheric pressure and 273.15–363.15 K. The high-pressure density at the pressures up to 50 MPa was also measured at 298.15–353.15 K. Meanwhile, CO 2 solubility in these phosphonium-based ionic liquids was determined using a magnetic suspension balance at 303.15–333.15 K and pressures up to 6 MPa. The experimental density and viscosity at atmospheric pressure were fitted using quadratic and Vogel-Fulcher-Tammann equations, respectively. The high-pressure density was fitted using the Tait equation and Sanchez-Lacombe equation of state. The properties of the two ether-functionalized ionic liquids were compared to those of triethylpentylphosphonium bis(trifluoromethanesulfonyl)amide [P 2225 ][TFSA]. The density at atmospheric pressure increased in the order [P 2225 ][TFSA] < [P 222(2O1) ][TFSA] < [P 222(1O1) ][TFSA]. The introduction of the ether group effectively reduced viscosity in the following order: [P 222(1O1) ][TFSA] < [P 222(2O1) ][TFSA] < [P 2225 ][TFSA]. The CO 2 solubilities in [P 222(1O1) ][TFSA] and [P 222(2O1) ][TFSA] were slightly lower than those in [P 2225 ][TFSA]. In contrast, the molality of CO 2 (m 1) increased in the order [P 2225 ][TFSA] < [P 222(2O1) ][TFSA] < [P 222(1O1) ][TFSA]. Ether functionalized phosphonium-based cations are effective in enhancing the physical absorption of CO 2 , particularly the molality of CO 2. [ABSTRACT FROM AUTHOR]

• Thermophysical properties of tri- n -butyl phosphate + propan-2-ol, or + butan-2-ol. • Composition-temperature-dependent molecular interactions in the binary mixtures. • Theoretical derivation of mixture properties using correlative approaches. • Derivation of new UNIFAC-VISCO group-interaction parameters for organophosphates. Densities, viscosities, and refractive indices of binary liquid mixtures of tri- n -butyl phosphate (TBP) with propan-2-ol and butan-2-ol at different temperatures between 303.15 and 323.15 K at an interval of 5 K and across the entire range of composition were measured. The data were used to calculate derived properties, such as excess molar volumes, excess thermal expansivities, deviations in viscosities, excess free energies of activation for viscous flow, and deviations in refractive index. The variation patterns of these properties concerning composition and temperature for the propan-2-ol + and butan-2-ol + TBP systems were discussed and attributed to probable intermolecular hydrogen bonding and geometric effects. Notably, the influence of hydrogen bonding was substantial, as evidenced by trends in excess molar volumes and deviations in viscosities. Concentration-dependent polynomial equations were used to fit the measured data of density, viscosity, and refractive index, while Redlich-Kister-type equations were applied for the excess properties. The densities and viscosities were correlated using the Jouyban-Acree model. The correlating abilities of various models, such as Grunberg-Nissan, Tamura-Kurata, Heric, Ausländer, McAllister-3, and McAllister-4 body models, were also evaluated using the viscosity data. Additionally, six new pairs of UNIFAC-VISCO group interaction parameters were computed to predict viscosities of TBP in systems involving alkanes, aromatics, and alcohols, extending the application range of the group contribution model. [ABSTRACT FROM AUTHOR]

• Novel method to determine vapor–liquid equilibrium of low volatility liquid or liquid mixtures and a compressed gas. • Mass Balance method based upon the measured density, system volume, and total mass of each component in the system. • Results compare favorably with "gold standard" precision microbalance method. • Compatible with a number of simultaneous thermophysical property measurements, e.g viscosity, speed of sound, spectroscopy, etc. Vapor-liquid equilibria measurements involving liquids with low volatility, such as many types of lubricants, ionic liquids, and various solvents are essential for process research and development in a wide variety of fields. State–of–the–art methods to measure these phase equilibria, e.g. thermogravimetric analysis or equilibrium cells, generally cannot be combined with instruments measuring thermophysical properties, e.g. density, transport properties, spectroscopic properties, etc. A novel approach was developed to measure simultaneously vapor–liquid equilibrium and thermophysical properties involving a single gas dissolved in one or more low-volatility liquids. The method is based upon a mass balance measuring liquid phase density, total masses in the system, and volumes. The governing equations of the novel approach are derived, and a detailed uncertainty analysis is presented. As an example, the solubility, density, and viscosity are measured with the new apparatus for a system of a non-volatile ionic liquid solvent saturated with the compressed hydrofluorocarbon gas, pentafluoroethane (R-125), at 25 °C and 75 °C and pressures to ∼ 3.1 MPa. The solubility data are validated by comparison to previously published literature data using a high precision gravimetric microbalance. The combination of vapor–liquid equilibria and thermophysical properties in a single experiment can significantly accelerate scientific and engineering studies. [ABSTRACT FROM AUTHOR]

• MD is a reliable method to calculated viscosities of PEC7 and PEC9. • Detailed MD simulations are given. To better understand the lubrication characteristics of refrigeration-compressor mechanical moving parts, the thermophysical properties of lubricants in a wide operating range of pressure should be well known, especially viscosity and density. However, the experimental data are always limited, particularly for higher pressures where experiments are difficult to implement. To obtain viscosity and density of lubricants in extreme pressures using a more cost-effective method, the densities and viscosities of pentaerythritol tetraheptanoate (PEC7) and pentaerythritol tetranonanoate (PEC9) were calculated using molecular dynamics (MD) simulations at the temperature range from 263.15 to 343.15 K and pressure range from 0.1 to 1.0 GPa. Compared to the experimental data at low pressures, the maximum relative deviations for density simulations of PEC7 and PEC9 are respectively 0.65 % and 0.70 %. The maximum relative deviations for viscosity simulations of PEC7 and PEC9 are respectively 18.9 % and 5.82 %. MD simulations combined with COMPASS forcefield can successfully calculate the densities and viscosities of pentaerythritol esters. [ABSTRACT FROM AUTHOR]

The development of biofuels to replace fossil fuels has recently increased at an exponential rate. Many chemical molecules with a wide range of functional groups make up biofuels. There is a strong correlation between the interactions between these molecules and the performance of biofuels. In this paper, the authors presented the new findings related to interactions existing in ethyl propionate and Formamide(F), N-Methylformamide (NMF), and N, N-Dimethylformamide (DMF) in a pure state as well as in their mixtures. Densities and speeds of sound at various temperatures (298.15–323.15 K) and at ambient pressure 0.1 MPa have been measured for these mixtures. From experimental data, the excess properties such as excess molar volume, V m E , excess isentropic compressibility, κ s E , excess molar isentropic compressibility, K s , m E , excess speed of sound, u E , and excess isobaric thermal expansivity, α p E , of the investigated mixtures were calculated. All the excess parameter values were fitted using the Redlich-Kister polynomial smoothing equation. The results were analysed in terms of molecular interactions. The excess partial molar volume, V ¯ m , 1 E , V ¯ m , 2 E , excess partial molar isentropic compressibility, K ¯ s , m , 1 E K ¯ s , m , 2 E over the whole composition range together with partial molar volume, V ¯ m , 1 0 , V ¯ m , 2 0 , partial molar isentropic compressibility K ¯ s , m , 1 0 , K ¯ s , m , 2 0 , excess partial molar volume, V ¯ m , 1 0 E , V ¯ m , 2 0 E and excess partial molar isentropic compressibility, K ¯ s , m , 1 0 E , K ¯ s , m , 2 0 E at infinite dilution have also been calculated from the experimental density measurements and analytically obtained using Redlich-Kister polynomials. The variations of these parameters with changes in composition and temperature have been discussed in terms of intermolecular interactions prevailing in these mixtures. [ABSTRACT FROM AUTHOR]

• Density and viscosity of ChCl-MDEA DES aqueous solution were measured. • Negative V E shows domination of intermolecular hydrogen bond and filling effect. • The increase in temperature and water content weakens the interaction between molecules. • Both Δ η and V E are temperature dependent. • Excessive water could destroy the supramolecular structure of DES. Amine-based deep eutectic solvents have the advantages of easy preparation, extremely low vapor pressure, stable biodegradation and high CO 2 loading, which has become the most potential CO 2 absorbent. In this work, the amine-based functionalized DES of choline chloride + methyldiethanolamine with different molar ratios were successfully prepared, and the densities and viscosities of DES aqueous solutions were measured from 303.15 K to 333.15 K. The effects of DES composition, water content and temperature on the excess molar volume, partial molar volume, apparent molar volume, limiting partial molar volume and viscosity deviation were investigated. The hydration and intermolecular interaction in DES solution were analyzed. The critical concentration of water in solution was determined under the premise of maintaining DES hydrogen bond network. [ABSTRACT FROM AUTHOR]

• Compressibility, density and sound velocity for two-phase LiF + CsCl melt are investigated. • Critical temperature of the liquid-liquid phase transition is 1257 K, the critical compressibility is 271.9 TPa−1, the critical sound velocity is 1257 m s−1, the critical density is 2030 kg m−3. The adiabatic compressibility, β , of the immiscible liquid mixture (LiF + CsCl) along the saturation line was experimentally investigated in the temperature range from the melting point to the critical mixing temperature using sound velocity values, u , measured by the pulse method, and density quantities, ρ , determined using the hydrostatic weight procedure based on the relationship β = u −2 ρ −1. The coefficients of the temperature dependencies for the compressibility, sound velocity and density of the upper and lower equilibrium phases have opposite signs because of the superposition of the thermal motion intensity of the ions and the change in the phase compositions. The differences Δ β , Δ u and Δ ρ for the equilibrium phases decrease with temperature elevation. The temperature dependencies of the compressibility, sound velocity and density difference are described using the empirical equations Δ β ≈ (T c − T) 1.004, Δ u ≈ (T c − T) 1.003 and Δ ρ ≈ (T c − T) 0.504. [ABSTRACT FROM AUTHOR]

• Compression of water + acetamide mixture were measured. • Measurements were performed at pressures to 100 MPa and temperatures from 278.15 to 323.15 K. • Molar isothermal compression and isobaric expansion of the mixture were evaluated. The density ρ at atmospheric pressure and compression ratios k = Δ V / V o of the {water (1) + acetamide (2)} mixture in the range of temperature from 278.15 K to 323.15 K (278.15, 288.15, 298.15, 308.15, 323.15), pressures from 10 to 100 MPa (10, 25, 50, 75 and 100) and in a wide range of compositions (maximum mole fraction of acetamide (AA) x 2 = 0.3875) were measured in the work. The partial molar volumes of both components V ¯ 1 and V ¯ 2 in the mixture, molar isothermal compression K T , m , molar isobaric thermal expansion E P , m , isochoric coefficient of thermal pressure β V , and internal pressure of the mixture P int were calculated. The volume characteristics for an infinitely dilute AA solution in water: limiting partial molar volumes V ¯ 2 ∞ , limiting partial molar isothermal compression K ¯ T ,2 ∞ , and limiting partial molar isobar expansion E ¯ P ,2 ∞ were calculated. The obtained results are discussed from the standpoint of interactions of solute-solvent and solute-solute. The obtained results are discussed in terms of solute-solvent and solute-solute interactions. [ABSTRACT FROM AUTHOR]

• Interactions between IL and organic solvent were investigated. • Density and speed of sound for ternary IL systems were measured. • Excess molar volume were calculated from density data. • Deviation properties were calculated from both density and speed of sound data. • Cibulka equation were used to correlate excess/deviation properties. The present investigation deals with the possible molecular interactions (such as intra and inter) between the component molecules in liquid mixtures by the addition of the third component (acetonitrile) to the ([C 4 mim][SCN] + acetic or propionic acid) binary system. Therefore, we present the excess molar volume (V 123 E), isentropic compressibility (k s) and deviation in isentropic compressibility (Δ k s 123) for the ternary systems {[C 4 mim][SCN] + acetic or propionic acid + acetonitrile} at temperature range of (293.15–313.15) K and at a pressure of 0.1 MPa with aid of density (ρ), speed of sound (u) measurements. Satisfactory correlation for the excess properties have been obtained using the Cibulka equation with the aid of Redlich–Kister parameters fitted to the corresponding binary systems obtained from literature data. Furthermore, the results obtained from the present study were discussed in terms of molecular interactions and effect of temperature on interactions. [ABSTRACT FROM AUTHOR]

• Densities, conductivities, fluorescence and UV–vis absorption spectroscopy of amino acid + [DOM][MAN] + water mixtures. • Hydrophilic-hydrophobic and hydrophobic-hydrophobic interactions between [DOM][MAN] and amino acids are dominate. • Rise in temperature increases the cmc values of [DOM][MAN] and the V 2 , φ 0 values of amino acids. • Addition of amino acids in water decreases the values of cmc and N agg of [DOM][MAN]. • The size of alkyl chain of amino acids affects the interaction between [DOM][MAN] and amino acids. Molecular interactions between some amino acids (glycine, l -alanine, l -valine and l -leucine) and a pharmaceutically active ionic liquid domiphen DL-mandelic acid ([DOM][MAN]) in aqueous solution at various temperatures have been studied by means of volumetric, conductivity and spectroscopy measurements. Density data were used to derive standard partial molar volume, V 2 , φ 0 standard partial molar expansibility, E φ 0 , standard transfer volume, Δ t V 0, isobaric thermal expansion coefficient, α 0 and hydration number, n H of amino acids. On the basis of the experimental conductivity and fluorescence spectroscopy data, the aggregation behaviour of [DOM][MAN] in aqueous amino acid solutions was investigated. Critical micelle concentration, cmc , aggregation number, N agg , some thermodynamic functions, Δ G m 0 , Δ H m 0 , Δ S m 0 and Δ C p 0 of micellization for [DOM][MAN] have been obtained. Effect of concentration and temperature on the obtained parameters has been discussed. Binding constant K b for amino acid-[DOM][MAN] complex estimated using the UV–vis spectroscopic data approved that the solute-solvent interactions were strengthened by elevating the size of alkyl part of amino acids. [ABSTRACT FROM AUTHOR]

• Densities and viscosities for binary and ternary solutions of MEA, DEEA and H 2 O were measured. • Excess molar volume, partial molar volume and apparent molar volume were calculated. • Viscosity deviation, activation enthalpy, activation entropy and Gibbs free energy were calculated. • Volumetric and viscometric properties were analyzed through the molecular structure and intermolecular interactions. The densities and viscosities of binary mixtures monoethanolamine (MEA) + H 2 O, 2-(Diethylamino)ethanol (DEEA) + H 2 O, MEA + DEEA and ternary mixtures MEA + DEEA + H 2 O were measured over the entire composition at temperatures ranging from (293.15 to 333.15) K and atmospheric pressure. The volumetric and viscometric properties such as excess molar volume, partial molar volume, partial molar volume at infinite dilution, apparent molar volume, viscosity deviation, molar enthalpy, molar entropy and the molar Gibbs energy of activation for viscous flow of mixtures were calculated in terms of experimental data, respectively. Furthermore, excess molar volumes were fitted by the Redlich–Kister equation for binary mixture and by Cibulka equation for ternary solution. The volumetric and viscometric properties were analyzed through the molecular structure and intermolecular interactions. [ABSTRACT FROM AUTHOR]

• Molecular interaction studies were carried out for the binaries {[Emim][triflate] + 2-ethoxyethanol/2-propoxyethanol}. • Density and speed of sound are measured at 298.15, 303.15, 308.15, 313.15 and 318.15 K. • The interactions in both the systems are analyzed in terms of excess parameters. • Observed interactions are well explained in terms of PFP theory. Physical properties, such as density (ρ) and speed of sound (u) of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 2-ethoxyethanol/2-propoxyethanol and their binary mixtures are measured over the whole composition range as a function of temperature between 298.15 K and 318.15 K at atmospheric pressure. Experimental values were used to calculate the excess molar volumes (V m E), excess values of partial molar volumes ( V ¯ m E), excess values of isentropic compressibility (κ s E), free length (L f E), speeds of sound (u E) and isobaric thermal expansion coefficient (α P E) for the binary mixtures. These excess properties were fitted to the Redlich-Kister type equation to obtain the binary coefficients and the standard deviations. A qualitative analysis of these parameters indicates the interaction decreases with the increase in chain length. This was further supported by Prigogine–Flory–Patterson (PFP) theory of excess molar volume. [ABSTRACT FROM AUTHOR]

• Densities and speeds of sound of saccharides in aqueous KOX solutions. • Positive apparent molar volumes predict dominance of solute-solvent interactions. • Positive transfer volumes indicate ion-ion interactions in the mixtures. • Pair and triplet interaction coefficients predict pair wise interactions in mixtures. The values of density, ρ and speed of sound, u for the saccharides that are structural isomers i.e. D(+)-glucose and D(−)-fructose in (0.2, 0.4, 0.6, and 0.8) mol·kg−1 aqueous solutions of dipotassium oxalate (K 2 C 2 O 4) at T = (288.15, 298.15, 308.15 and 318.15)K have been measured in the present work. Various volumetric parameters such as apparent molar volume (V ϕ) , partial molar volume at infinite dilution (V ϕ o), transfer volume (Δ V ϕ o), have been derived from density records. Experimental values of the speed of sound were used to calculate ultrasonic parameters such as apparent molar isentropic compressibility (K ϕ , s ), partial molar isentropic compressibility at infinite dilution (K ϕ , s o), and partial molar isentropic compressibility of transfer (Δ K ϕ , s o). The pair (V AB , K AB) and triplet interaction (V ABB , K ABB) coefficients have been calculated from transfer parameters by using McMillan-Mayer theory. The structure-making/structure-breaking affinity of the saccharides along with a detailed insight into the physicochemical interactions e.g. ion-hydrophilic, hydrophilic–hydrophilic and hydrophilic-hydrophobic interactions in the saccharide-salt system, have been retrieved through the scrutiny of these calculated parameters. [ABSTRACT FROM AUTHOR]

• Using MDEA to prepare of phosphonium-based transition temperature mixtures (TTMs). • There was only glass transition temperature in DSC curves of solvents, not the freezing point. • RSM was used to investigate the significance of molar ratio and temperature. • Decreasing density and refractive index data by increasing the amount of MDEA in the mixture. • ANOVA results showed the greater effect of molar ratio than the temperature on the properties. In this study, three mixtures of methylyltriphenylphosphonium bromide (MTPPB) as hydrogen bond acceptor (HBA) and N -methyl diethanolamine (MDEA) as hydrogen bond donor (HBD) component was used to prepare transition temperature mixtures (TTMs) into different mole ratios of 1:7, 1:10 and 1:16 HBA/HBD. Two important physicochemical properties of TTMs such as density and refractive index were investigated at the atmospheric pressure and temperature ranges of (293.15–353.15) K and (293.15–343.15) K, respectively. The experimental density data were used to derive the molar volume, molecular volume, lattice energy and isobaric thermal expansion coefficients. With the help of experimental refractive index data, the electronic polarization, molar refraction, and free volume were calculated at the whole temperatures. Several empirical equations were used to correlate refractive indices such as an empirical equation and one-parameter equations (Dale–Gladstone, Eykman, Lorentz–Lorenz, Newton, Arago–Biot, and Oster). Finally, the response surface methodology (RSM) was applied to evaluate the effects of two main factors such as temperature and mole ratio on the density and refractive index of TTMs. The results revealed that the molar ratio has almost a higher effect on the studied properties than temperature. [ABSTRACT FROM AUTHOR]

• ρ and u have been measured of ethyl butyrate with isomeric butanediols between 298.15 and 323.15 K. • Thermophysical parameters have been calculated. • The effect of temperature has been discussed on excess derived properties in terms of intermolecular interactions. • The influence of intra molecular hydrogen bond was analyzed and it is high for 1,4-butanediol. Today biofuels are emerging in an exponentially manner in order to replace the fossil fuels. Biofuels are composed of several organic compounds containing wide variety of functional groups. The interactions existing among these compounds play a significant role in the efficiency of the biofuels. In this paper, the authors presented the new findings related to interactions existing in ethylbutyrate and α, ω -alkanediols in pure state as well as in their mixtures. Densities and speeds of sound at various temperatures (298.15–323.15) K and at ambient pressure 0.1 MPa have been measured for these mixtures. From experimental data, the excess properties such as excess molar volume, V m E , excess isentropic compressibility, κ s E , excess molar isentropic compressibility, K s , m E , excess speed of sound, u E , and excess isobaric thermal expansion, α p E , of the investigated mixtures were calculated. All the excess parameter values were fitted using the Redlich-Kister polynomial smoothing equation. The results were analysed in terms of molecular interactions. The partial molar volumes, V ¯ m,1 and V ¯ m,2 , partial molar isentropic compressibilities, K ¯ s,m,1 and K ¯ s,m,2 , excess partial molar volumes, V ¯ m,1 E and V ¯ m,2 E and excess partial molar isentropic compressibilities, K ¯ s,m,1 E and K ¯ s,m,2 E over whole composition range; the excess partial molar quantities of the components at infinite dilution have been calculated. The variations of these parameters with change in composition and temperature have been discussed in terms of intermolecular interactions prevailing in these mixtures. The V m E values for these mixtures were also calculated by using Prigogine–Flory–Patterson (PFP) theory and the results were compared with experimental findings. [ABSTRACT FROM AUTHOR]

• The ionic liquid, [TMG(C 2) 2 ][NTf 2 ], has been synthesized and characterized. • Densities and viscosities of binary mixtures of IL with alcohols are reported. • H-bond interactions are revealed with DFT calculations. • Relationship among interaction, structure and property has been investigated. The guanidinium-based ionic liquid (IL), 2,2-diethyl-1,1,3,3-tetramethylguanidinium bis(trifluoromethylsulfonyl)imide ([TMG(C 2) 2 ][NTf 2 ]), was synthesized. Densities and viscosities of the IL and its mixtures with methanol or ethanol were reported at temperatures from 293.15 K to 323.15 K. The increment of IL concentration or the decrement of temperature significantly increases both density and viscosity. Excess molar volume (V m E) and viscosity deviation (Δ η) of each binary mixture were calculated, and the Redlich–Kister equation was used to fit V m E and Δ η with composition. When V m E is negative with the mole fraction of IL (x 1) lower than 0.8 for two systems, Δ η is negative over the whole concentration range. The positive V m E of the mixture at a high IL concentration indicates that interaction loss occurs. Moreover, structures of the equimolar mixture of IL and alcohol were obtained by DFT calculations, and alcohol–anion, alcohol–cation and cation–anion interactions were revealed. Strong H-bond interaction with the span of 1.61 Å is formed between the H atom of the OH group in alcohol and the O atom in the [NTf 2 ]− anion, while the O atom of the OH group in alcohol interacts with the methyl groups in the [TMG(C 2) 2 ]+ cation. Significant cation–anion interactions (<2.40 Å) in the manners of H⋯F and H⋯O with spans less than 2.40 Å are found at the same time. It is the enhanced H-bond interactions that contribute to the negative V m E of the equimolar mixture at non-concentrated regions. [ABSTRACT FROM AUTHOR]

• The densitities (ρ), viscosities (η) and speeds of sound (u) of vinyl acetate + ethers have been determined experimentally. • The mixture viscosities were correlated using Hind, Heric and McAllister's (4-body) models. • Excess or deviation properties indicate presence of weak interactions (dispersion forces). Densities, viscosities and speed of sound of binary liquid mixtures of vinyl acetate with butyl vinyl ether, diisopropyl ether, anisole, and dibutyl ether are presented over the complete concentration range at (303.15, 308.15 and 313.15) K and 0.1 MPa. Excess volume, deviations in viscosity, isentropic compressibility, deviations in isentropic compressibility were calculated from the measured data and fitted to the Redlich-Kister Polynomials. Viscosity data were also correlated using Hind, Heric and McAllister (4-body) models. [ABSTRACT FROM AUTHOR]

Variations of apparent molar volumes, V ϕ vs. molality, m of l -alanine in 2% semicarbazide hydrochloride + water at temperatures, T /K = 293.15, ♦; T /K = 298.15, ■; T /K = 303.15, ▲; T /K = 308.15, ●; T /K = 313.15, □; T /K = 318.15, Δ. • Reports ρ , u and η data of α-amino acids in semicarbazide hydrochloride + water solutions. • Study elucidates interactions of amino acids with semicarbazide hydrochloride in aq. media. • Structure-making/-breaking tendency of α-amino acids in these media is investigated. • Thermodynamics of viscous flow has also been investigated. • Groups' contributions of amino acids to various parameters have been calculated. Various non-covalent interactions can be scrutinized by the measurement of physical properties. The nature of interactions between drugs and amino acids governs the functionalization process, so a better understanding demands reliable thermophysical data. Keeping this in mind, we report herein the densities, ρ , ultrasonic speed, u and viscosities, η of glycine, l -alanine, l -valine and l -isoleucine in aqueous-semicarbazide hydrochloride (1 wt% and 2 wt% semicarbazide hydrochloride in water) solvents in the temperature range of 293.15–318.15 K at an interval of 5 K and at atmospheric pressure. The density data have been used to calculate the apparent molar properties like V ϕ , V ϕ ° and transfer volume, V ϕ , t r °. From the ultrasonic speed data, thermo-acoustical parameters, such as K s , ϕ , K s , ϕ ° and transfer compressibility, K s , ϕ , t r ° have been evaluated. The viscosity data have been used to calculate Falkenhagen Coefficient, A , Jones-Dole coefficient, B. The hydration numbers, n H has also been evaluated. The entropies, Δ S ° # and enthalpies, Δ H ° # activation parameters, Δ μ 1 ° # and Δ μ 2 ° # were also calculated. The co-sphere overlap model was used to interpret the positive V ϕ , t r ° values. In addition, the values of V ϕ ° , K s , ϕ ° , B and Δ μ 2 ° # have been split into groups' contributions of the amino acids. [ABSTRACT FROM AUTHOR]

• Densities are measured for two oligomeric blend systems of PEG ethers + PEG ester over a wide pressure range. • The studied oligomeric PEG ethers are PEG mono-4-octylphenyl ether (PEGOPE) and PEG mono-4-nonylphenyl ether (PEGNPE). • The studied oligomeric PEG ester is PEG mono-laurate (PEGML). • Excess volumes are negative over the majority of composition range mainly due to hydrogen-bonding effect. • The P - V - T data are correlated satisfactorily with the Flory-Orwoll-Vrij and the Schotte equations of state. Densities are measured for two binary systems of oligomeric blends, polyethylene glycol mono-4-octylphenyl ether) (PEGOPE) + polyethylene glycol mono-laurate (PEGML) and polyethylene glycol mono-4-nonylphenyl ether (PEGNPE) + PEGML, at temperatures from 298.15 K to 348.15 K and pressures up to 50 MPa. The excess volumes are negative for these two binary systems over the majority of composition range, except for the regions near pure components, in which the values may change into positive. Tait equation represents accurately for the pressure-effect on the liquid densities. Additionally, a generalized equation with two characteristic parameters correlates well the P - V - T data over the entire experimental conditions for each binary system. Those P - V - T data are also correlated satisfactorily with the Flory-Orwoll-Vrij (FOV) and the Schotte equations of state with one binary interaction parameter for each oligomeric blend system. [ABSTRACT FROM AUTHOR]

• A new double-path pulse-echo instrument was developed for measuring the speed of sound in fluids. • The speed of sound in p-xylene was measured, from which additional thermodynamic properties were derived. • Comparison with the current Helmholtz EOS indicated that it should be revised using new experimental data. The speed of sound in p -xylene has been measured at temperatures ranging from (306 to 447) K and at pressures from just above saturation to 66 MPa. Measurements were performed using a new double-path pulse-echo instrument, fabricated from Invar 36, that was designed for ease of assembly and calibration as well as robust operation. The cell's path length was calibrated with water at a single state point against the IAPWS-95 equation of state, with path length corrections for temperature and pressure calculated using material-property data. Validation measurements on water over the range of experimental conditions investigated resulted in deviations from IAPWS-95 smaller than the equation's relative uncertainty of 0.1 %. The expanded relative uncertainty of the measurements over the reported ranges of pressure and temperature varied from (0.023 to 0.104) % at 95 % confidence. The measured data for p -xylene were compared with the Helmholtz equation of state (EOS) of Zhou et al., which is stated to have a relative uncertainty in sound-speed of 0.3 % in the liquid region. Relative deviations between experiment and the EOS of up to 1 % were observed, especially at high temperatures and low pressures, indicating that the current Helmholtz model should be revised using the new experimental data. Additionally, density, isobaric specific heat capacity, and other thermodynamic properties of p -xylene were derived from the speed-of-sound data by thermodynamic integration; these results expand upon the available literature data and are generally in good agreement with the current Helmholtz EOS. The relative expanded uncertainties for liquid density and isobaric specific heat capacity in this work are estimated to be 0.2 % and 1 %, respectively, equivalent to the uncertainty of the EOS. [ABSTRACT FROM AUTHOR]

• Densities and viscosities of IL + 2-alkanol mixtures were measured. • Partial molar volumes and thermal expansibility for mixtures were calculated. • All data of binary mixtures are new and reported for first time. New experimental data of density and viscosity for the binary mixtures of 1-butyl-3-methylimidazolium nitrate ([Bmim][NO3]) with + 2-propanol, 2-butanol and 2-pentanol are reported over the entire range of mole fraction at T = (293.15–323.15) K. To elucidate possible intermolecular interactions between the chemical species present in solutions, the excess molar volume, V m E thermal expansion coefficient, α excess thermal expansion coefficient, α E the isothermal coefficient of excess molar enthalpy, ∂ H m E / ∂ P T , x partial molar volume, V i ¯ and deviation in viscosity, Δ η were calculated. The excess molar volume of the binary mixture is negative over the entire mole fraction range and becomes more negative with increase in the temperature. Deviation in the viscosity is negative over the whole range of composition and decreases with increasing temperature. The obtained excess molar volume and deviation in viscosity were fitted to the Redlich–Kister polynomial equation. The experimental results have been discussed regarding molecular interactions and the formation of complex between unlike molecules. Influences of temperature and carbon chain length of alcohols were discussed. [ABSTRACT FROM AUTHOR]

Highlights • Short chain length FAMEs and FAEEs used as model fuels. • Surface light scattering method used for determined the surface properties. • Large amount of thermophysical property data for six FAMEs and six FAEEs. • Corresponding models of the investigated thermophysical properties. Abstract In present study, surface light scattering (SLS) was used for the simultaneous determination of liquid surface tension and kinematic viscosity of twelve fatty acid esters, including six methyl esters (FAMEs) and six ethyl esters (FAEEs). The SLS apparatus was firstly checked with a reference fluid n -dodecane, and a good agreement of our data from SLS with those from literatures could be found. By utilizing this apparatus, both properties were investigated in the temperature ranges between (298 and 448) K for all substances with an exception of methyl myristate and ethyl myristate covering the temperatures between (323 and 448) K due to their high melting points. Additionally, the liquid density and refractive index were determined by an Anton Paar U-tube densimeter between (293 and 453) K and a refractometer from (278 to 358) K, respectively. The surface tension and viscosity data obtained from the SLS experiment were fitted to the van der Waals type and the reciprocal temperature-dependent polynomial equations, respectively. The quadric and linear functions were adopted to correlate the density and refractive index data, respectively. This work improves the data situation for these fatty acid esters especially at elevated temperatures and provides necessary data and models for the crucial thermophysical properties in connection with the design and optimization of the injection system of an internal combustion engine (ICE). [ABSTRACT FROM AUTHOR]

Highlights • Densities and viscosities of MDEA, MEA and ethanol mixed solutions were measured. • Excess molar volume and the partial molar volume were calculated and correlated. • Viscosity deviations of binary and ternary solutions were obtained and correlated. • Intermolecular interactions were analyzed based on the volumetric properties. Abstract The densities and viscosities of binary solutions of (N-methyldiethanolamine + ethanol), (monoethanolamine + ethanol) and (N-methyldiethanolamine + monoethanolamine) as well as ternary solution of (N-methyldiethanolamine + monoethanolamine + ethanol) were measured at T = 293.15 K, 303.15 K, 313.15 K, 323.15 K. The volumetric and viscometric properties, such as the excess molar volume V E, the partial molar volume V ¯ , the partial molar volume at infinite dilution V ¯ ∞ and the viscosity deviation Δ η , were calculated from the experimental densities and viscosities. The excess molar volumes and viscosity deviations of binary and ternary solutions were correlated by the Redlich-Kister equation and the Cibulka's equation, respectively. The intermolecular interactions in binary and ternary solutions were analysed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Densities and ultrasound speeds of 24 aqueous mixtures of 1-butanol were experimentally determined. • Excess molar and partial molar volumes, isentropic compressions and isobaric expansions were derived. • Different sensitivities were detected in the water very-rich region regarding volumes and isentropic compressions. • Limiting partial molar properties were interpreted in terms of hydration features. Abstract Simultaneous measurements of density and sound speed, at five temperatures, T = (283.15–303.15) K and pressure, P = 0.1 MPa within the miscible composition range were performed in 24 aqueous liquid mixtures of 1-butanol. Composition and temperature effects on different excess molar, and excess partial molar properties such as volume, isobaric expansion and isentropic compression are analysed, in terms of different changes in the hydration and association patterns, across the composition ranges studied. Comparison of the different thermodynamic properties, derived for this system, with those for two aqueous system of smaller number of carbon atoms is made. Limiting excess partial molar volumes, isobaric expansions and isentropic compressions at both ends of the composition range are presented. Limiting partial molar isentropic compression values for 1-butanol, infinitely diluted in water, compare very well with values calculated by the group contribution scheme previously presented by some of us. [ABSTRACT FROM AUTHOR]

Highlights • Multipolar interactions were added to SAFT-VR Mie leading to PSAFT-VR Mie and tPSAFT-VR Mie. • tPSAFT-VR Mie performed better than the SAFT-VR Mie with an adjustable λ a. • For associating molecules tPSAFT-VR Mie is equivalent to SAFT-VR Mie. • tPSAFT-VR Mie successfully correlated speed of sound of the evaluated substances. • No model reproduces the unusual behavior of this property for water. Abstract Polar forces affect significantly the thermodynamic properties and phase equilibria of pure fluids. In this work, the original SAFT-VR Mie equation of state was modified by the introduction of an explicit term to account for multipolar effects. Two approaches were evaluated: the Polar SAFT-VR Mie (PSAFT-VR Mie) and the Truncated Polar SAFT-VR Mie (tPSAFT-VR Mie). For non-associating molecules the agreement between experimental data and model predictions are very good. The tPSAFT-VR Mie equation of state presented better results than the SAFT-VR Mie and PSAFT-VR Mie models correlating condensed-phase density, condensed-phase speed of sound, saturated density and saturated pressure with lower deviations. For associating molecules the results obtained with the tPSAFT-VR Mie model were equivalent to the ones obtained with the SAFT-VR Mie equation of state. In order to the tPSAFT-VR Mie model better predict second-derivative thermodynamic properties, such as the speed of sound and the isobaric heat capacity, some information about this type of property must be used in the pure components parameters regression. All evaluated models predicted similar values for the second virial coefficient. [ABSTRACT FROM AUTHOR]

Highlights • Densities and volumetric properties were determined for furfural + alcohols. • Densities and volumetric properties were determined for 2-methylfuran + alcohols. • Excess molar volumes were correlated with Redlich-Kister equation. • Solute partial molar volumes increase with the alcohol carbon chain length. • Excess molar volumes are smaller for furfural systems than for 2–methylfuran. Abstract In this work, densities, excess molar volumes, partial molar volumes and excess partial molar volumes for binary liquid mixtures of furfural and 2–methylfuran with 1–propanol or 2–propanol or 2–butanol or 1–pentanol or 2–pentanol or 1–hexanol at 298.15 K and 0.1 MPa over the entire range of composition were determined. Excess molar volumes were correlated with Redlich–Kister equation with average absolute deviations smaller than 0.0164. Excess molar volumes were negative for furfural + 1–propanol or 2–propanol and positive for all other studied binary systems. Solute partial molar volumes determined increase as alcohol carbon chain length increase, except for furfural + 2–pentanol, which presented smaller values than 2–butanol for molar fractions below 0.2. A maximum/minimum was observed from the excess partial molar volume plots. FTIR spectra data indicate bands at 3135 cm−1, for furfural systems, and 3122 cm−1 for 2–methylfuran systems, are related to the behavior found for excess molar volumes and that H–bonds are smaller for furfural systems than for 2–methylfuran. [ABSTRACT FROM AUTHOR]

Highlights • [N 111 C 3 MIM][N(CN) 2 ] 2 was synthesized and characterized. • Heat capacity and thermal stability were experimentally determined. • Densities and viscosity of [N 111 C 3 MIM][N(CN) 2 ] 2 mixtures with IPA were measured. • Excess properties were calculated. • Nature of interactions between [N 111 C 3 MIM][N(CN) 2 ] 2 and IPA were discussed. Abstract A novel asymmetrical gemini ionic liquid, 1-(3-(trimethylammonio)prop-1-yl)-3-methylimidazolium bis(dicyanamide) ([N 111 C 3 MIM][N(CN) 2 ] 2), was synthesized and characterized by 1H NMR, 13C NMR. Thermal stability of [N 111 C 3 MIM][N(CN) 2 ] 2 was investigated through thermogravimetric analysis under pure nitrogen atmosphere. Heat capacity of pure [N 111 C 3 MIM][N(CN) 2 ] 2 was measured using differential scanning calorimetry in the temperature range 298.15–423.15 K and enthalpy H T -H 298.15K , and entropy S T -S 298.15K were obtained. Densities and viscosities were measured for the binary system of [N 111 C 3 MIM][N(CN) 2 ] 2 and isopropanol (IPA) over the entire range of mole fractions at various temperatures from 283.15 to 333.15 K under the pressure of 0.101 MPa. Moreover, the excess molar volumes (V m E) and the viscosity deviations (Δ η) for the binary mixtures were determined and well fitted to the Redlich−Kister polynomials. The negative values of V m E and Δ η result from strong self-association and weak hydrogen bonding interaction between the molecules of [N 111 C 3 MIM][N(CN) 2 ] 2 and IPA. Excess Gibbs energy of activation (Δ G *E) of viscous flow for the present binary mixtures were also calculated. Results have been discussed in terms of molecular interactions and structures. [ABSTRACT FROM AUTHOR]

Highlights • Experimental CO 2 and H 2 S solubility were measured in pure 2,2′-thiodiglycol. • Experimental solubility data were modelled using Peng-Robinson-Stryjek-Vera cubic EoS. • Thermodynamic solubility quantities were reported at infinitely diluted 2,2′-thiodiglycol. Abstract The solubility of acid gases such as CO 2 and H 2 S in 2,2-thiodiglycol (TDG) were measured by static method so called isochoric saturation within the temperature range (303.15–353.15) K by steps of 10 K and pressure up to 1.2 MPa. To calculate the absorption behaviour of gases, density of 2,2-thiodiglycol at the related temperature range was measured with Anton Paar SVM 3000, as well. The outcome solubility data were modelled using Stryjek-Vera modification of Peng-Robinson cubic equation of state (PRSV EoS), and thermodynamic solubility quantities at infinitely diluted solution in 2,2-thiodiglycol were reported. [ABSTRACT FROM AUTHOR]

Highlights • The densities for amine + alcohol six binary solutions were measured. • The V m E values are negative with x MEA from 0 to 1. • For straight chain alcohol mixtures, V m E values follow: ethanol < n-propanol < n-butanol. • For branched chain alcohol mixtures, V m E values follow: tertbutanol < isobutanol < n-butanol. • V m E values were correlated with Redlich-Kister polynomial equation. Abstract In this experimental, the densities of monoethanolamine (MEA) + alcohol binary mixtures were measured at temperatures from (293.15 to 333.15) K at 0.1 MPa. The studied alcohols include straight-chain ones, ethanol, n-propanol and n-butanol, and branched-chain ones, isopropanol, isobutanol and tertbutanol. From the experimental density values, we calculated the molar volume (V m), the thermal expansion coefficient (α p) and excess molar volume (V m E). The V m E values for the six binary systems are all negative ranging from (−1.020 to −0.064) cm3·mol−1. For straight-chain alcohol mixtures, the V m E values follow the increasing order of ethanol < n-propanol < n-butanol. And for the branched-chain alcohol mixtures, the V m E values follow the increasing sequence of tertbutanol < isobutanol < n-butanol. All these result from the intermolecular interactions and structural characteristics. For smaller ethanol molecule and MEA, the molar volume is quite similar to each other. However, V m E value for ethanol + MEA system is the most negative. Therefore, the formation of hydrogen bonds plays a leading role for excess molar volume in small molecule alcohol systems. On the other hand, for larger butanol molecule + MEA systems, steric effect leads to a decrease in excess molar volume with the increase in butanol molar volume. Furthermore, the V m E values were correlated with Redlich-Kister polynomial equation with the largest deviation of 0.048. [ABSTRACT FROM AUTHOR]

Highlights • Deep eutectic solvents based on choline chloride were characterized with NMR, FT-IR, TGA and surface tension. • Densities and viscosities were measured for deep eutectic solvents and their pseudo-binary mixtures with 1-butanol. • Enthalpies of mixing were obtained for pseudo-binary mixtures of deep eutectic solvent + 1-butanol. Abstract Ionic liquids and deep eutectic solvents have aroused interest as alternative solvents for separation processes due to their favourable properties. For instance, deep eutectic solvents are usually biodegradable, non-toxic, low cost and also share some properties with ionic liquids, such as their tuneability to be used in specific applications. Recently, deep eutectic solvents have been studied more extensively but their physicochemical characterization is still in the initial stages if the final objective is to select alternatives for industrial processes. Decomposition temperature, surface tension, density, and viscosity were measured for deep eutectic solvents based on choline chloride as the hydrogen bond acceptor and levulinic acid, ethylene glycol and phenol as hydrogen bond donors (in a 1:2 mol ratio). Density, viscosity and excess enthalpy were measured for pseudo-binary mixtures of the different deep eutectic solvents with 1-butanol. The excess properties were calculated to understand the behaviour of the deep eutectic solvents in the mixture. The results suggest that deep eutectic solvents are formed due to strong intermolecular forces between their constituents, with no reaction observed. This generates a higher thermal stability of the deep eutectic solvents compared to their constituent hydrogen bond donor. Also, with the addition of 1-butanol to the deep eutectic solvents, the mixture has a lower volume compared with the ideal case due to the creation of new networks of hydrogen bonds and interstitial site accommodations. Hence, the excess molar volumes and excess enthalpies have a negative deviation from the ideal behaviour. The viscosity deviation is related to the Arrhenius equation observing a negative deviation for the deep eutectic solvents containing levulinic acid and phenol, and a positive deviation for the one with ethylene glycol. Experimental data for the different properties allows a qualitative understanding of the magnitude of the interactions that occur when mixing deep eutectic solvents with 1-butanol. [ABSTRACT FROM AUTHOR]

Graphical abstract Variations of apparent molar volume, V ϕ vs. molality, m of isoniazid in 10% sucrose + water at temperatures, T /K = 293.15, ♦; T /K = 298.15, ■; T /K = 303.15, ▲; T /K = 308.15, ●; T /K = 313.15, □; T /K = 318.15, Δ. Highlights • Reported ρ , u and η data of the drug isoniazid in glucose/sucrose + water solvents. • Study elucidates interactions of isoniazid with carbohydrates in aqueous media. • Study correlates physical properties of isoniazid with its interactions in mixed media. • Thermodynamics of viscous flow has also been investigated. Abstract The densities, ρ , ultrasonic speeds, u and viscosities, η of the drug isoniazid in water and in aqueous– d -glucose/ d -sucrose (5 wt% and 10 wt% glucose/sucrose in water) solvents were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and at atmospheric pressure. The ρ , u and η data have been used to calculate apparent molar volumes, V ϕ , limiting apparent molar volumes, V ϕ ∘ , apparent molar compressibilities, K s , ϕ , limiting apparent molar compressibilities, K s , ϕ ∘ , transfer volumes, V ϕ , t r ∘ and transfer compressibilities, K s , ϕ , t r ∘. The viscosity data have been used to determine Falkenhagen Coefficients, A and Jones-Dole coefficients, B. The calculated parameters have been discussed in terms of various solute-solute and solute-solvent interactions prevailing in these solutions. The structure making/breaking ability of isoniazid in these solutions has been examined by using the sign of d B /d T. Furthermore, the Gibbs energies of activation of viscous flow per mole of solvent, Δ μ 1 ∘ # and per mole of solute, Δ μ 2 ∘ # , enthalpies, Δ H ∘ and entropies, Δ S o of activation of viscous flow, were also calculated and discussed in terms of transition state theory. [ABSTRACT FROM AUTHOR]

Highlights • Switchable hydrophilicity solvent systems were prepared and the physicochemical properties were measured. • Properties were density, viscosity, refractive indices, and thermal conductivity. • The volumetric and viscometric methods were used to interpret results. • Solute-solvent interactions predominated over solute-solute interactions. Abstract For switchable hydrophilicity solvent (SHS) systems (N,N -Dimethylcyclohexylamine (DMCA), water, and carbon dioxide): the density, viscosity, refractive index and conductivity at (283.15–308.15) K and 0.1 Mpa, were measured. The apparent molar volumes were determined as a function of composition at each temperature from experimental data. Based on Masson's equation limiting apparent molar volumes and Masson's coefficient S V describing the character of interactions were calculated. The relative viscosity values were adjusted to obtain the viscosity B coefficients and dB/dT values. It has been observed that there exist strong solute-solvent and solute-solute interactions in these systems, and DMCAH-bicarbonate salt acts as structure-maker in aqueous solvent. [ABSTRACT FROM AUTHOR]

Highlights • Interactions between unlike molecules are stronger than those between like ones. • There are different interaction modes between N -min and water, and alcohols. • The predominant interactions are N -mim: alcohols = 1:1 hydrogen-bonded networks. • Alcohols' alkyls and N -mim's methyl are electro-withdrawing and -donating groups. • Interactions between unlike molecules weaken with the alcohols alkyl chain growth. Abstract Over a full molar fraction range, for binary mixtures of x N -methylimidazole (hereafter abbreviated to N -mim) + (1 − x) water, +methanol, +ethanol, +1-propanol, +2-propanol, the mass density and sound velocity at (288.15, 298.15, 308.15, 318.15, 328.15) K, the mixing enthalpy at 298.15 K, and 1H NMR measurements, combined with the Ab initio calculations, have been carried out. The excess molar volume, excess average volume expansivity, excess sound velocity, excess isentropic compressibility, and the molar mixing enthalpy were calculated and fitted to a Redlich-Kister equation. The partial molar enthalpy of N -mim, the difference between the partial molar volume and the molar volume of N -mim, and the protons chemical shift changes were calculated and compared. The chemical shifts of N -mim protons, hydroxyl protons, and α -H (proton on the carbon atom next to the –OH group) of alcohols in the mixtures containing alcohols were explained by a model proposed by Gupta et al.. The properties indicate that the intermolecular interactions between unlike molecules are stronger than those between like molecules. An increase in temperature has a greater influence on the mixture containing water than on pure components, and has a greater influence on pure components than on mixtures containing alcohols. The predominant interactions between unlike molecules are hydrogen-bonded complexes in the mixture containing water, and are N -mim: alcohols = 1:1 hydrogen-bonded networks in the mixtures containing alcohols, where the alkyl groups of alcohols are electron-withdrawing groups, and the methyl group of N -mim is an electron-donating group. Ab initio calculations proved that the N⋯HO hydrogen bond in the mixtures is more stable and stronger than HO⋯HO in pure water or in pure alcohols and N⋯HC in pure N -mim. The strength sequence of the intermolecular interactions between unlike molecules for the mixtures at 298.15 K is N -mim–water > N -mim–methanol > N -mim–ethanol > N -mim–1-propanol ≥ N -mim–2-propanol. [ABSTRACT FROM AUTHOR]

Highlights • Nonaqueous MEA + EGME mixtures have proposed as chemical absorbents for CO 2 capture. • Physical properties of CO 2 -free and CO 2 -loaded MEA + EGME systems were measured. • Experimental data were well correlated by the proposed models. • The AADs are within 4.5% for (ρ , η) and 19.5% for CO 2 solubility respectively. Abstract Non-aqueous amine-based absorbents are considered as a potential application for CO 2 removal from biogas to reduce energy consumption, due to lower heat capacity and evaporation enthalpy of organics than conventional water solvent. In this work, monoethanolamine (MEA) + 2-methoxyethanol (EGME) mixtures were proposed as a novel CO 2 carrier. The density and viscosity of CO 2 -free and CO 2 -loaded MEA + EGME solutions were measured at temperatures of (293–353) K, for 10–100 mass % MEA. CO 2 solubility in 31.0 mass% (5.0 M) MEA solutions was investigated at temperatures from 313 K to 393 K and CO 2 partial pressures up to 260 kPa. The excess molar volumes and the ratio of viscosity η · η EGME −1 were correlated by Redlich-Kister equation and Weiland's model, respectively. The vapour-liquid equilibrium data were correlated by using a semi-empirical model, i.e. CO 2 partial pressure as a function of temperature and CO 2 loading. The predicted values and the measured data matched well each other, with AAD within 0.2% for density, 4.5% for viscosity and 19.5% for CO 2 solubility respectively. [ABSTRACT FROM AUTHOR]

Graphical abstract Excess molar volume, V m E as function of mole fraction, x 1 of BN for BN + alkyl methacrylate binary mixtures at 298.15 K. Highlights • Reports new density data of benzonitrile (BN) + alkyl methacrylate mixtures. • Reports new speed of sound data of BN + alkyl methacrylate mixtures. • Provides computation of excess properties of BN + alkyl methacrylate mixtures. • Shows the effect of alkyl chain length on physicochemical properties and their derived parameters. • Reduced excess molar volume approach was applicable to these mixtures. Abstract Experimental measurements of densities and ultrasonic speeds for the binary mixtures of benzonitrile with methyl/ethyl/ n -butyl methacrylates over the entire composition range were carried out in the temperature range 293.15 K–318.15 K and atmospheric pressure of 0.1 MPa. Using the experimental data, the excess molar volume, excess ultrasonic speed, excess isentropic compressibility, and excess molar isentropic compressibility have been calculated and correlated by Redlich-Kister equation. The partial molar and excess partial counterparts of molar volumes and molar compressibilities over the whole composition range; and at infinite dilution have also been calculated. The dependence of these parameters on composition and temperature has been interpreted in terms of intermolecular interactions prevailing in these mixtures. The order of interactions suggested by the excess functions is found to be MMA > EMA > BMA. The major cause of the order is the steric hindrance caused by alkyl group. The results showed the effect of varying chain length on excess functions and interactions of the system. [ABSTRACT FROM AUTHOR]