Isentropic Compressibility Research Articles

Review of Density and Ultrasonic Velocity of Various Complexes and Its Applications

This review paper delves into the fundamental principles, measurement techniques, and diverse applications of ultrasonic velocity and density. Ultrasonic velocity serves as a crucial parameter in various fields such as materials science, acoustics, and medical diagnostics whereas density is used for identifying substances, quality control, analyzing mixtures, assessing purity, explaining buoyancy, determining concentrations, calibrating instruments, monitoring pollution, and understanding reactivity. This paper provides an in-depth exploration of the underlying concepts, different measurement methods, and the wide-ranging applications of ultrasonic velocity and density. The ultrasonic velocity and density data have also been used to evaluate various acoustic parameters such as isentropic compressibility, apparent isentropic molar compressibility, solvation number of the solute and relative association. Ultrasonic velocity measurements are found to be useful for on-line assessment of the extent of degradation of mechanical properties associated with precipitation of intermetallics. Keywords: Density, Ultrasonic velocityThis review paper delves into the fundamental principles, measurement techniques, and diverse applications of ultrasonic velocity and density. Ultrasonic velocity serves as a crucial parameter in various fields such as materials science, acoustics, and medical diagnostics whereas density is used for identifying substances, quality control, analyzing mixtures, assessing purity, explaining buoyancy, determining concentrations, calibrating instruments, monitoring pollution, and understanding reactivity. This paper provides an in-depth exploration of the underlying concepts, different measurement methods, and the wide-ranging applications of ultrasonic velocity and density. The ultrasonic velocity and density data have also been used to evaluate various acoustic parameters such as isentropic compressibility, apparent isentropic molar compressibility, solvation number of the solute and relative association. Ultrasonic velocity measurements are found to be useful for on-line assessment of the extent of degradation of mechanical properties associated with precipitation of intermetallics. Keywords: Density, Ultrasonic velocity

Thymoquinone-Micellar Interactions: A physico-chemical investigation at molecular level

Thymoquinone (TQ) is considered the most-active component of the well-known essential oil of the black cumin/seeds (Nigella sativa L.), also known for its wide-spectrum anticancer and other pharmacological potentials since ancient times. Apart from its thermo- and photo-sensitive nature, TQ has also been reported to demonstrate strong hydrophobicity and low bioavailability. These physico-chemicals, properties hinder the development of a successful oral dosage formulation. Interaction of the pharmacologically active molecule with biological membranes is crucial step to manifest health-related effects. However, further insight into the biophysical interactions of “active” natural chemotherapeutics with cellular membranes can play a vital role in designing and developing new anti-cancer regimens. In this context pseudo-membrane models comprising ionic and non-ionic micelles offer a useful way to explore in vitro drug-membrane interactions at the molecular level. The present study focuses on the physicochemical interactions of a thymoquinone (TQ) with micelles of ionic (dodecyl trimethylammonium bromide, DTAB; and sodium dodecyl sulfate, SDS) and non-ionic (tween-80 and TX-100) surfactants at the molecular level in aqueous medium. Volumetric and acoustic parameters (apparent molar volume (ɸV), isentropic compressibility (Ks), apparent molar isentropic compressibility (ɸk), specific acoustic impedance (Z), relative association (RA), intermolecular free length (Lf)) are calculated from experimental data of density and sound velocity and interpreted in terms of solute/solvent–solute/solvent interactions using the co-sphere overlap model and the electrostriction effect. Further, UV spectroscopy and conductivity studies are used to predict the locus of TQ in the micelles, binding constant (Kb), partition coefficient (Kc), and free energy changes of TQ-micelle systems in the presence of surfactants. The results show that the binding and partitioning of TQ is more significant with TX-100 as compared with other ionic and non-ionic surfactants used.

Interaction study of L-phenylalanine/glycyl-L-phenylalanine in water-soluble 1-decyl-3-methylimidazolium bromide ([C10mim]Br) ionic liquid: thermodynamic/physicochemical approaches

AbstractRecent times have witnessed notable progress in augmenting the effectiveness of pharmaceutical actions, leading to the creation of novel drug formulations and delivery technologies. A complete understanding of the molecular-level interactions between drug molecules and biological membranes is necessary to achieve optimal design in these processes. Comprehensive understanding of these interactions can be gained through thermodynamic research, which helps pharmaceutical professionals make well-informed decisions about which manufacturing compounds are most suited for a certain application. Because ionic liquids can interact with biological membranes and exert their effects on them, studying ionic liquids in combination with co-solvents in aqueous settings is important for many kinds of research. Using an Anton Paar DSA 5000 M apparatus, the densities, and speed of sound in a liquid mixture comprising L-phenylalanine and glycyl-L-phenylalanine within an aqueous 1-decyl-3-methylimidazolium bromide ([C10mim]Br), the ionic solution was measured. This was done across temperature ranges of 288.15 K, 298.15 K, 308.15 K, and 318.15 K and experimental pressure of p = 0.1 MPa with concentrations of “0.000, 0.005, 0.030, and 0.050 mol kg–1”. From the experimental results, various acoustic and physicochemical properties were derived, including apparent molar properties, partial compression, isentropic compression, and transfer properties. These computations provided insights into intermolecular interactions within the combination of 1-decyl-3-methylimidazolium bromide, water, L-phenylalanine, and glycyl-L-phenylalanine. The mixture’s characteristics were explored through pair and triplet coefficients, taking into account empirical constants and expansibilities, thereby delving into solute–solvent, hydrophilic-hydrophilic, dipole–dipole, and ion-hydrophilic interactions. Graphical Abstract

Excess Properties, Partial Volume per Mole and FITR Spectral Studies in Liquid Mixtures of Furfuryl Alcohol with Primary and Secondary Anilines

ABSTRACT Speeds of ultrasound and densities of Furfuryl alcohol (FFA), Aniline (AN), N-Methylaniline (NMA) and N-Ethylaniline (NEA) along with the binary mixtures FFA+AN, FFA+NMA, FFA+NEA are measured at temperatures (303.15–318.15) K. From the experimental speed of ultrasound and density, excess parameters namely excess intermolecular free length ( L f E ), excess volume per mole ( V m E ) and deviation in isentropic compressibility (∆κs) are determined. The result of excess properties is supported by excess partial volume per mole ( V ˉ m , i E ) studies. The calculated excess and deviation functions have been fitted to the Redlich-Kister polynomial equation, and the observations have been analysed in terms of molecular associations. The variation of these excess parameters indicated the presence of specific interactions between component molecules. Further, FTIR spectra for the three mixtures were recorded and analysed to correlate with the thermodynamic and volumetric results. A good agreement was found between the two studies.

Kinetic studies of surfactant-aspirin micellization by means of ultrasonic relaxation spectroscopy

We report on the dynamics of the Sodium dodecyl sulfate (SDS) – aspirin micellization process taking place in aqueous environment by combining vibrational and ultrasonic spectroscopies. The experimental vibrational spectra have been compared with the corresponding theoretically predicted spectra obtained by density functional theory electronic structure calculations. The formation of a swollen SDS@aspirin micelle above a specific surfactant concentration significantly affects several physical properties of the system including surface tension and isentropic compressibility allowing the estimation of the critical micelle concentration. In the acoustic spectra, a single ultrasonic relaxation process has been detected in SDS-aspirin-water solutions at concentrations slightly above critical micelle concentration. The variation of the sound absorption coefficient and velocity as a function of frequency at different concentrations reveals the presence of a relaxation process attributed to the perturbation of the monomer-micelle dynamic equilibrium. We progress on the comprehensive understanding of the micellization kinetics, and the results are discussed in the context of several theoretical models of the field.

Investigations on the thermo physical properties of the binary mixtures of 2-methyl-pentanediol-2,4 with n-alkanols at various temperatures (hexylene glycol with 1-octanol, 1-nonanol, 1-decanol)

ABSTRACT Densities (ρ), speeds of sound (u) and viscosities (η) for three binary mixtures of hexylene glycol (2-methyl-2,4-pentanediol or MPD) with 1-octanol (D1), 1-nonanol (D2) and 1-decanol (D3) are calculated at temperatures ranging from 303.15 to 313.15 K and atmospheric pressure over the entire composition range. Experimental measurements are used to calculate the excess molar volume, excess isentropic compressibility, deviation in viscosity and excess Gibbs-free energy of activation of viscous flow. Partial molar properties and infinite dilution molar partial properties are also calculated for each binary system. The results obtained can be discussed in terms of weaker interactions and dispersion forces with the absence of specific intermolecular interactions in binary mixtures. Finally, the Prigogine-Flory-Patterson (PFP) theory is applied to identify the most predominant molecular interaction. Jouyban-Acree model results are discussed in terms of mean relative deviation (MRDs) and individual relative deviation (IRD) between calculated and experimental densities, speeds of sound and viscosities as an accuracy criterion.

Study of thermodynamic, transport and volumetric properties of nanofluids containing ZrO2 nanoparticles in polypropylene glycol, polyvinyl pyrrolidone and water.

Zirconium dioxide (ZrO2) nanofluids are used in cooling systems, solar energy, and heat exchangers, offering improved heat transfer and efficiency across a wide temperature range. The aim of this work was to study the influence of polypropylene glycol (PPG) and polyvinyl pyrrolidone (PVP) and aqueous solutions of them as a base fluid on stability, volumetric properties, and viscosity of nanofluids containing Zirconium oxide (ZrO2) nanoparticles. The stability of these nanofluids has been confirmed using UV-Vis spectroscopy, and the particle size distribution of the systems using dynamic light scattering (DLS). Among these systems ZrO2-PPG and ZrO2-H2O-PVP30% have appropriate stability. The density, speed of sound and viscosity of these nanofluids have been measured at T = (293.15 to 318.15) K. From these data, the excess molar volume (V E m) and isentropic compressibility (κ s) have been determined. The effects of ZrO2 nanoparticles and temperature have also been investigated on volumetric and transport properties of aqueous solutions of PPG and PVP. The (V E m) values were fitted to the Redlich-Kister, Ott et al., and polynomial equations. Also, the isentropic compressibility (κ s) values were correlated with the polynomial equation. The Eyring-NRTL and Eyring-mNRF models have been used for correlating of the viscosity of the nanofluids with temperature dependency. The performance of the Einstein, Brinkman, Lundgren and Batchelor models in the prediction of viscosity of the nanofluids has also been analyzed.

Physiochemical properties of the binary liquid mixtures of 2-methyl-2,4-pentanediol with selected di- and tri-chloro-substituted benzene and correlation with the Jouyban–Acree model at various temperatures

ABSTRACT Excess molar volume, excess isentropic compressibility, deviation in viscosity and excess Gibbs free energy for the activation of viscous flow for binary mixtures of 2-methyl-2,4-pentanediol (MPD) with 1,2-dichlorobenzene (1,2-DCB), 1,3-dichlorobenzene (1,3-DCB) and 1,2,4-trichlorobenzene (1,2,4-TCB) components selected compositions are determined from the measured values of densities (ρ), speeds of sound (u) and viscosities (η) of pure components and their mixtures from 303.15 K to 313.15 K. The results are analysed in terms of intermolecular interactions or hydrogen bonding or hetero-association interactions in the binary mixtures. The Prigogine–Flory–Patterson (PFP) theory is applied to identify the predominant molecular interaction. The results of Jouyban–Acree model are discussed in terms of mean relative deviation (MRD) and individual relative deviation (IRD) between the calculated and experimental densities, speeds of sound and viscosities as accuracy criteria.

Expanding the Pressure Frontier in Grüneisen Parameter Measurement: Study of Sodium Chloride.

The Grüneisen parameter (γ) is crucial for determining many thermal properties, including the anharmonic effect, thermostatistics, and equation of state of materials. However, the isentropic adiabatic compression conditions required to measure the Grüneisen parameter under high pressure are difficult to achieve. Thus, direct experimental Grüneisen parameter data in a wide range of pressures is sparse. In this work, we developed a new device that can apply pressure (up to tens of GPa) with an extremely short time of about 0.5ms, confidently achieving isentropic adiabatic compression. Then, we applied our new technique to sodium chloride and measured its Grüneisen parameter, which conforms to previous theoretical predictions. According to our obtained sodium chloride Grüneisen parameters, the calculated Hugoniot curve of the NaCl B1 phase appears up to 20GPa and 960K, which compares very well with the shock compression experimental data by Fritz etal. and other calculation works. Our results suggest that this new method can reliably measure the Grüneisen parameter of even more materials, which is significant for researching the equation of state in substances.

Comprehensive Thermodynamic Performance Evaluation of Various Gas Liquefaction Cycles for Cryogenic Energy Storage

This paper conducts comparative thermodynamic analysis and performance evaluations of various gas liquefaction configurations. The four most common liquefaction systems (Linde–Hampson, Kapitza, Heylandt, and Claude) were considered. The isothermal and multi-stage isentropic compression processes were evaluated and compared as actual compression processes. Thermodynamic evaluation is based on the energy required to compress a unit mass of gas, the liquefied air mass flow rate, and the exergetic efficiency. The modeling results show that three-stage compression cycles retain lower energy requirements. Increasing the compression stage from one to two for all the processes decreases the energy requirement by 34 to 38%. Changing the compression stage number from two to three reduces the energy requirement by 13%. The compression pressure and expander flow rate ratio significantly affect the liquefied air mass flow rate. Hence, a parametric analysis was conducted to obtain the best operating conditions for each considered cycle. Depending on the compression pressure, the optimum expander flow rate values of the Claude, Kapitza, and Heylandt cycles change from 0.65 to 0.5, 0.65 to 0.55, and 0.35 to 0.30, respectively. For the optimum cases, the Claude, Kapitza, and Heylandt cycles result in liquid yields that are about 2.5, 2.2, and 1.6 times higher than that of the Linde–Hampson cycle. The Claude cycle is the best operating cycle for all the considered performance metrics. Moreover, the performances of the Linde–Hampson and Claude cycles are investigated for various gases. Under the same operating conditions, the results show that better performance parameters are obtained with the gases that have relatively high normal boiling temperatures.

Volumetric, acoustic, and optical properties of binary mixtures of diethyl ether with alkanol at T = 293.15 K to 303.15 K

Density (ρ), ultrasonic speed (u), and refractive index (nD) of binary liquid mixtures such as diethyl ether (DEE) (1) + alkanol (isomers of propanol and 1-butanol) (2) were experimentally measured at T = 293.15 K to 303.15 K and at 0.1 MPa pressure. By using these measurements excess molar volume (VmE), deviation in ultrasonic speed (Δu), excess isentropic compressibility (κsE), and deviation in refractive index (ΔnD) were computed and associated with the Redlich-Kister polynomial equation. It was found that deviation parameters are influenced by H–bonding, interstitial accommodation, and dipole–dipole molecular interactions between binary mixtures. The VmE values have been interpreted by the Prigogine–Flory–Patterson (PFP) theory and the Flory–Treszczanowicz–Benson (FTB) model. The FTB model and PFP theory anticipated the VmE curves and were able to depict the perfect shape and magnitude of VmE values. The numeric values of u and nD were computed by using several empirical correlations and mixing rules. This study discusses the comparative significance of these relationships with the measured values of u and nD.

Density and speed of sound of (iodobenzene + n-alkane) liquid mixtures at T = (288.15 to 308.15) K. Application of the Prigogine-Flory-Patterson model

(Iodobenzene + n-alkane) liquid mixtures have been studied experimentally, in terms of densities (ρ) and speeds of sound (c), and theoretically, by the application of the Prigogine-Flory-Patterson (PFP) model. The n-alkanes considered are n-heptane, n-decane, n-dodecane, and n-tetradecane. ρ and c measurements have been performed at a pressure p = 0.1 MPa and in the temperature range T = (288.15 to 308.15) K. Excess molar volumes (VmE) and excess isentropic compressibilities (κSE) have been calculated and correlated by Redlich-Kister polynomials. (∂VmE/∂T)p curves at the same (p,T) conditions have been obtained from correlated VmE values. The mixtures are characterized by the following features: (i) VmE increases with the number of carbon atoms of the n-alkane (n), being negative for n = 7, small and S-shaped with positive and negative values for n = 10, and positive for n = 12 and n = 14; (ii) κSE and (∂VmE/∂T)p are negative, increase with n and are very close to zero for n = 14. From these experimental results and the knowledge of the excess molar enthalpies of mixtures containing fluorobenzene, chlorobenzene or bromobenzene with n-alkanes, we have inferred the presence of structural effects, especially important for n = 7 and less relevant for volumetric properties as n increases. The VmE obtained are compared with those of other (halogenated benzene + n-alkane) liquid mixtures existing in the literature, namely systems with fluorobenzene, chlorobenzene, and bromobenzene. From this comparison and the analysis of the isobaric thermal expansion coefficients of the pure compounds, it is inferred that the interactional effects on VmE do not vary appreciably with the length of the n-alkane, so the observed VmE variation is fundamentally determined by the corresponding variation of the contribution from structural effects. Moreover, the application of the PFP model supports this interpretation, providing free volume contributions to VmE that vary parallelly to VmE with the length of the n-alkane, and interactional contributions that rest approximately constant independently of the n-alkane size.

Molecular interactions between 2-methyltetrahydrofuran and alcohols: A combination of thermodynamic, spectroscopic and quantum chemistry studies

New data of density (ρ), viscosity (η), and speed of sound (u) have been determined at T = (288.15–303.15 K) and p = 93.2 kPa for the binary mixture of {2-methyltetrahydrofuran + ethanol, or + 1-propanol, or + 1-butanol, or + 1-pentanol} over the entire composition range. These results were used to calculate the excess molar volume (VmE), isentropic compressibility deviation (Δκs), viscosity deviation (Δη), and Gibbs excess activation energy (ΔG*E), which were correlated by a Redlich-Kister polynomial. For all systems studied, the values ​​of the deviation properties were negative, which probably indicates a predominance of structural and chemical effects over physical effects. Five viscosity models were employed to fit the viscosity data. The VmE data were also correlated by the Prigogine-Flory-Patterson Theory (PFP Theory) and the Peng-Robinson-Stryjek-Vera Equation of State (PRSV EOS). Furthermore, a Fourier Transform Infrared (FT-IR) spectroscopy study was performed to explain the hydrogen bonding interactions. Lastly, theoretical calculations using Density Functional Theory (DFT) at B3LYP-GD3(BJ)/6–311++G(3df,2p) level of theory were performed to understand the inter-interactions between the compounds present in the mixtures. The FT-IR and computational results were in good agreement with the experimental data.

Volumetric and acoustic studies of binary mixtures of DEC with isomeric chlorobenzene at various temperatures

ABSTRACT Densities, ρ, and speeds of sound, u, of binary liquid mixtures of diethyl carbonate with 1,2-dichlorobenzene, 1,3-dichlorobenzene and 1,2,4-trichlorobenzene have been measured over the entire range of composition at 303.15 K, 308.15 K, 313.15 K and 318.15 K and at atmospheric pressure. From the experimental data of the density and speed of sound, 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 , have been calculated. For better knowledge of the solute and solvent interaction, excess partial molar volumes, V ˉ m , 1 E and V ˉ m , 2 E , and excess partial molar volumes, V ˉ m , 1 ∘ E and V ˉ m , 2 ∘ E of the components at infinite dilution have been measured. All the excess parameter values have been fitted using the Redlich–Kister polynomial smoothing equation. The calculated excess values have been analysed in terms of molecular interactions and structural effects.

Acoustic and volumetric study of binary mixtures containing Ethyl propionate with amides at various temperatures

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, VmE, excess isentropic compressibility, κsE, excess molar isentropic compressibility, Ks,mE, excess speed of sound, uE, and excess isobaric thermal expansivity, αpE, 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,1E, V¯m,2E , excess partial molar isentropic compressibility, K¯s,m,1EK¯s,m,2E over the whole composition range together with partial molar volume, V¯m,10, V¯m,20, partial molar isentropic compressibility K¯s,m,10, K¯s,m,20, excess partial molar volume, V¯m,10E, V¯m,20E and excess partial molar isentropic compressibility, K¯s,m,10E,K¯s,m,20E 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.

Thermodynamic characterization of aqueous solutions of NaCl, KCl, MgCl2 and CaCl2: volumetric, acoustic, viscometric and computational analysis

The volumetric and acoustic properties of alkali and alkaline earth metal salts are ubiquitous in numerous biological and non-biological processes and accurate formulation of their thermophysical properties is a fundamental prerequisite for complete exploration of their diverse applications. To meet this purpose, in this investigation, we herewith report the systematic data of densities ρ, speed of sound u and viscosity η of aqueous binary solutions of the prominent alkali and alkaline earth metal salts viz. NaCl, KCl, MgCl2, and CaCl2 at seven different temperatures T = (288.15–318.15 K) and ambient pressure over the wide concentration range of (0.002–1) mol∙kg−1.These experimental data have been further employed to obtain some important thermodynamic parameters, viz, the apparent molar volume of solute Vϕ, limiting apparent molar volume of solute Vϕ0, isentropic compressibility of solution κS, apparent molar isentropic compression of the solute KS,ϕ, limiting apparent molar isentropic compression of solute KS,ϕ0 and apparent molar expansibility Eϕ0. Further, the coefficient of thermal expansion α*, the second-order derivative of limiting apparent molar volume ∂2Vϕ0/∂T2, Jones-Dole equation viscosity A, B, D coefficients, temperature derivative of B coefficient i.e. dB/dT, activation parameters for viscous flow and hydration number nH have also been computed. The results obtained have been used to elucidate different interactions taking place in the aqueous electrolytic solutions. To corroborate the experimental results, quantum chemical calculations were performed using density functional theory (DFT) by Gaussian software package. The calculations included an analysis of molecular orbitals, with particular emphasis on the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO).

Acoustical Studies on Binary Mixtures of Methyl Acrylate with Benzene and Mono-Substituted Benzenes at 313.15 K

Ultrasonic velocities and Densities of binary mixtures of Methyl Acrylate (MA) with Benzene and mono-substituted Benzenes like Benzene (B), Methyl benzene (MB), and Ethyl benzene (EB) have been measured at 313.15 K, by using these data, various acoustical parameters like Isentropic compressibility (KS), Intermolecular free length (Lf), acoustic impedance (Z) and relative association (RA) were calculated, further by using these acoustical parameters, excess properties like excess ultrasonic velocities (uE), excess acoustic impedance (ZE), excess isentropic compressibility (KSE) and excess inter-molecular free-length (LfE) were calculated and fitted to Redlich-Kister equation. The existence of inter-molecular interactions between the components in the liquid mixtures was discussed.

Interactional behaviour of analgesic drugs in aqueous solution of caffeine at different temperatures using multi-technique approach

Drug combination therapies have been a promising strategy to overcome drug resistance. However, unexpected drug–drug interaction may cause adverse reactions, which puts patients in danger. Keeping this in mind, the interactions between pain killers, paracetamol (PCM), and ibuprofen sodium with caffeine (CAF) have been studied. Apparent molar volumes ( V2,ϕ) and apparent molar isentropic compression ( Ks,2,ϕ) for analgesic drugs in aqueous (1, 2, 5, and 10 mmol·kg−1) CAF solutions have been determined from measured densities, ρ, and speeds of sound, u, respectively, at T = 288.15–318.15 K and at pressure p = 101.3 kPa. The results have also been interpreted in terms of various interactions occurring in the mixed solution. Calorimetrically determined negative values of ΔtrΔdil H0 indicate the exothermicity and thus the occurrence of energetically more favorable process. The hyperchromic shift (UV absorption) in the spectra of PCM in aqueous solution of CAF suggests the dominance of solute–cosolute interactions through the hydrophobic–hydrophobic/hydrophilic groups (1H NMR) of PCM + CAF system.

Application of ERAS-model and PFP theory on excess and deviation properties for binary systems of ionic liquid + amine derivatives

Thermodynamics of mixtures includes ionic liquid 2-hydroxyethylammonium propionate [2-HEAPr] + 1-propanol, 3-amino-1-propanol [AP], 1-amino-2-propanol [MIPA], and monoethanolamine [MEA] were studied. Density ρ, speed of sound u, and refractive index nD of pure and mixtures were measured at T = (298.15, 308.15, 318.15) K. Excess molar volume VmE, excess partial molar volume Vm,iE, excess thermal expansion coefficient αE, isothermal coefficient of excess molar enthalpy (∂Hm∂P)T,x, deviations in isentropic compressibility Δ ks, and refractive index Δ nD were calculated and data correlated with Redlich-Kister polynomial relation. The Prigogine-Flory-Patterson (PFP) and Extended Real Associated Solution (ERAS) models were applied to analyze intramolecular and intermolecular interactions between like and unlike molecules. The accuracy of theoretical models were found to be in agreement with empirical results. Finally, the study confirmed the structures of the ILs using FT-IR and HNMR analysis.

A consistent framework to characterize the impact of co-solvents in the key process thermophysical properties of choline chloride-based DESs

In the pursuit of environmentally greener solvents, Deep Eutectic Solvents (DESs) have emerged as suitable solutions for diverse industrial applications. The reliable prediction of the physicochemical properties of DESs, affecting the design and operation of processes, is a challenging task that can be accelerated through computational modelling, reducing the amount of experimental work. The purpose of this contribution is to introduce a straightforward yet robust coarse-grained molecular model, able to characterize the thermodynamic properties of several choline chloride-based DESs, including the effect of water and alcohols as co-solvents. This is carried out using the soft-SAFT equation of state by developing an accurate and transferable parametrization. A description of the key properties of pure DESs and their mixtures, including density, speed of sound, isentropic compressibility, viscosity and activity coefficients, is provided and discussed thoroughly, revealing good agreement with the available experimental data. This methodology allows the screening of the thermophysical properties of DESs, whose knowledge is essential pre-requisite for process design.