Speed Of Sound Data Research Articles

Applications of Flory’s Statistical Theory to Ionic Liquids in the Extended Pressure Range and at Different Temperatures

Introduction: Flory’s statistical theory (FST), for the first time, has been applied successfully to two pure ionic liquids, [C3mim][NTf2] and [C5mim][NTf2], in an extended range of pressure (0.10 – 59.9 MPa) and at different temperatures (298.15 – 333.15 K). Methods: Density and sound speed data have been employed to compute a number of useful and important properties of these ionic liquids in the light of FST. Using Flory parameters (P*, T*, V*, P̃, T̃, Ṽ), the expression for the surface tension (σ) has been deduced in the form σ = σ* σ (Ṽ), with σ* and σ (Ṽ) being the characteristic and reduced values of surface tension. Since the experimental σ of liquids is not known, the validity of FST has been tested by calculating “u” using four different u-ρ- σ correlations, namely Auerbach (1948), Altenberg (1950), Singh et al. (1997), and Modified Auerbach (2016). Results: Several useful and important properties of ionic liquids, under varying physical conditions, have been deduced and compared to the observed ones with a quite satisfactory agreement. Such properties include Pint, van der Waals constants (a & b), parachor [P], Eötvas constant (kB), energy (ΔEV) and heat of vaporization (ΔHV), cohesive energy density (ced), polarity index (n), and solubility parameter (δ). Conclusion: In this study, the validity of FST to two ionic liquids under the present study has been confirmed.

Solvation properties of l-lysine and l-arginine in aqueous solutions of 1-heptyl-3-methyl imidazolium tetrafluoroborate [C7mim][BF4]at different temperatures

Thermodynamic and physicochemical properties of lysine and arginine in aqueous and aqueous solution of 1-heptyl-3-methyl imidazolium tetrafluoroborate [C7mim][BF4] have been studied by measuring density and speed of sound data at T = (288.15–308.15 K) under atmospheric pressure. The measured data has been further used to calculate limiting partial molar volume, Vϕ0 , the limiting partial molar compression Kϕ,S0 , and limiting partial molar volumes of transfer, ΔtrVϕ0,and limiting partial molar isentropic compression of transfer ΔtrKϕ,S0 . Furthermore, structure making and structure breaking ability of solute has been discussed by evaluation of apparent molar expansivity, Eϕ0 , Hepler's constant values, ∂Eϕ0∂TP and hydration numbers, nH .

Physicochemical studies of L-valine and L-isoleucine in aqueous solutions of [Emim][HSO4] at different temperatures

The present work deals with experimental determination of density, speed of sound and viscosity (ƞ) data for L-valine and L-isoleucine in aqueous [Emim][HSO4] over range of concentration (0.0301–0.0702) mol kg−1 and temperature (293.15–313.15 K). The density and speed of sound data are used to evaluate the volumetric and compressibility parameters. Through the graphical fitting of the evaluated parameters in some standard relations the limiting apparent molar volume (Voϕ) and Limiting apparent molar isentropic compression (K°ϕ,s) are calculated. The transfer parameters of volume (ΔtrV°ϕ) and compressibility (ΔtrK°ϕ,S) studies evaluated using the limiting apparent molar parameters are used to deduct the solute–solvent interactions by means of the cosphere overlap model which shows that the hydrophilic-hydrophilic and ion-hydrophilic interactions are less dominant in the solution over the hydrophobic-hydrophobic and ion-hydrophobic interactions. The viscosity data is utilized to calculate the relative viscosity (ηr) and viscosity B-coefficient. The Helper’s constant and first temperature derivative of B-coefficients (dB/dT) has been used to analyze whether solute acts as structure maker or structure breaker in the solution.

Thermodynamic Properties of Liquid Toluene from Speed-of-Sound Measurements at Temperatures from 283.15 K to 473.15 K and at Pressures up to 390 MPa

We report the speeds of sound in liquid toluene (methylbenzene) measured using double-path pulse-echo apparatus independently at The University of Western Australia (UWA) and Imperial College London (ICL). The UWA data were measured at temperatures between (306 and 423) K and at pressures up to 65 MPa with standard uncertainties of between (0.02 and 0.04)%. At ICL, measurements were made at temperatures between (283.15 and 473.15) K and at pressures up to 390 MPa with standard uncertainty of 0.06%. By means of thermodynamic integration, the measured sound-speed data were combined with initial density and isobaric heat capacity values obtained from extrapolated experimental data to derive a comprehensive set of thermodynamic properties of liquid toluene over the full measurement range. Extensive uncertainty analysis was performed by studying the response of derived properties to constant and dynamic perturbations of the sound-speed surface, as well as the initial density and heat capacity values. The relative expanded uncertainties at 95% confidence of derived density, isobaric heat capacity, isobaric expansivity, isochoric heat capacity, isothermal compressibility, isentropic compressibility, thermal pressure coefficient and internal pressure were estimated to be (0.2, 2.2, 1.0, 2.6, 0.6, 0.2, 1.0 and 2.7)%, respectively. Due to their low uncertainty, these data and derived properties should be well suited for developing a new and improved fundamental Helmholtz equation of state for toluene.

Interaction studies of diglycine with aqueous solutions of sulphathiazole drug at different temperatures

The interactions of diglycine with sulphathiazole drug as a function of temperatures have been studied using volumetric and acoustic parameters. Densities and speeds of sound of diglycine in (0.001, 0.002,0.005, and 0.010) mol·kg-1 aqueous solutions of sulphathiazole drug have been measured at five different temperatures of (288.15,293.15,298.15,303.15 and 308.15) K under 0.1MPa pressure. From density data, the apparent molar volume (Vf), the partial molar volume ( ) and the standard partial molar volume of transfer ( ) for glycine from water to aqueous sulphathiazole solutions have been calculated. Partial molar isentropic compression and partial molar isentropic compression of transfer ( ) have been calculated from the speed of sound data. Transfer parameters by using cosphere overlap model have been explained from the point of view of concentration dependence of solute-solute and solute-solvent interactions. To draw the conclusion from the volumetric and acoustic data, limiting apparent molar expansion , as well as hydration numbers, have been studied. The calculated values of thermal expansion coefficient, , have small and positive values. All of these derived or calculated parameters are explained to understand the solvation behavior, mixing aspects and various types of interactions born in the ternary solutions of (drug + water + dipeptide) due to change in structure. We have also attempted to examine the temperature and concentration dependence of such interactions.

Volumetric and compressibility studies on aqueous mixtures of deep eutectic solvents based on choline chloride and carboxylic acids at different temperatures: Experimental, theoretical and computational approach

Deep eutectic solvents (DESs) constitute a new class of green solvents, the studies on which are going at a fast pace. The binary mixtures of DESs with water are attracting a great deal of interest for various industrial applications owing to their unique properties not exhibited by the neat components. Therefore, thermodynamic properties of DESs-water mixtures should be explored to better understand the prevailing intermolecular interactions for enhancing the application arena of such binary mixtures. Herein, the density (ρ) and speed of sound (u) of binary mixtures of DESs (choline chloride: acetic acid; 1: 2; and choline chloride: L-(+)-lactic acid; 1: 2) with water has been measured over whole composition range at different temperatures (T = 298.15 to 313.15 K) and atmospheric pressure. The values of various thermodynamic parameters have been derived and discussed in terms of the varying extent of intermolecular interactions governed by the components of DESs. The negative values of excess molar volumes (VmE) are ascribed to the stronger hydrogen bond interactions and efficient molecular packing in the binary mixtures over repulsive interactions. The VmE values have been analyzed using Prigogine-Flory-Patterson (PFP) theory, which satisfactorily explained the volumetric behaviour of the binary mixtures. Density functional theory (DFT) calculations have been made to support the variation in VmE and the underlying interactions prevailing between the components. Further, isentropic compressibility (ks) and excess isentropic compressibility (ksE) have been evaluated from the speed of sound data. It is expected that such studies will be beneficial from the academic as well as industrial point of view considering the increasing utilization of DESs for various applications.

Studies on volumetric and acoustic behfavior of L-alanine and L-leucine in aqueous 1-dodecyl-3-methylimidazolium bromide ionic liquid solutions at different temperatures

In this work density (ρ) and speed of sound (c) of a ternary system containing {1-dodecyl-3-methylimidazolium bromide + water + L-alanine or L-leucine} have been determined at five working temperatures, T= (288.15, 293.15, 298.15, 303.15 and 308.15) K. From density data, thermodynamic parameters like the apparent molar volumes (Vϕ), the apparent molar volumes at infinite dilution (Vϕ0) and partial molar volume of transfer ΔVϕ0has been determined. Speed of sound data has been used to determine parameters like partial molar isentropic compression (Kϕ,s), partial molar isentropic compression at infinite dilution (Kϕ,s0) and partial molar isentropic compression of the transfer ΔKϕ,S0. The limiting apparent molar expansibilities at infinite dilution ϕE0= (∂Vϕ0/∂T)p deliver valuable information about the (solute–solvent) interactions present in the system. These parameters provide information about the molecular interactions prevailing between amino acids and ionic liquid.

Effect of some choline based deep eutectic solvents on volumetric and ultrasonic properties of gabapentin drug in water at T = (288.15 to 318.15) K

A key part of the drug preparation process is the optimization of molecular interactions between drugs and solvents. Thermodynamic properties provides complete information on interactions and the selection of suitable solvents for various pharmaceutical processes. Especially, the investigation of antiepileptic drugs in aqueous solutions has been a subject of interest because they employ their effect by interaction with biological membranes. In this study, the density and speed of sound for the gabapentin (GBP) in aqueous deep eutectic solvents (DESs), (choline chloride/ethylene glycol (ChCl/EG), choline chloride/glycerol (ChCl/Gly), and choline chloride/urea (ChCl/U)) as novel category of green solvents were measured at temperature range 288.15 K to 318.15 K. The apparent molar volumes Vφ, apparent molar isobaric expansion Eφ0, Hepler’s constant and apparent molar isentropic compressibility κφ were calculated from the density and speed of sound data. Findings show that Vφ values are higher for binary systems compared to ternary systems. The order of Vφ values for aqueous DESs solutions are as follows: ChCl/EG > ChCl/U > ChCl/Gly. The standard partial molar volume Vφ0 and partial molar isentropic compressibility κφ0 were obtained by using the Redlich-Meyer equation. The obtained results for the Vφ0 quantity indicate a strong interaction between the GBP drug and the ChCl/Gly. Finally, using the results of Eφ0, it is understood that GBP has acted as a structure maker in the presence of all DESs.

Volumetric and 1H NMR spectroscopic studies of saccharides-calcium lactate interactions in aqueous solutions

The solute-solvent interactions governing the hydration behaviour of saccharide [D(+)-glucose, sucrose and D(+)lactose monohydrate) molecules were studied in aqueous solution of calcium salt at temperatures (298.15 K 313.15 K) and at atmospheric pressure. The volumetric properties were evaluated from experimentally measured densities and speed of sound data. The nature of interactions influencing the taste behaviour of saccharides in presence of calcium lactate is evaluated from apparent specific volume and apparent specific isentropic compressibility values. The volumetric transfer parameters (ΔtZ2° = ΔtV2° or ΔtK°s,2) were evaluated and the magnitude of these parameters were analysed on the basis of co-sphere overlap model. Among various interactions occurring in the system, hydrophobic types of interactions were found to be the dominating one. The 1H NMR of the studied system was recorded and from the variation in chemical shift (Δδ) it was further concluded the presence of hydrophobic-ionic types of interactions.

The effect of moisture content on the acoustic characteristic of bioenergy feedstocks—Corn Stover

Corn stover is increasingly being used as a bioenergy feedstock. From harvest to handling and storage, its inconsistent moisture content imposes limits on the industry's growth and profitability. We propose an acoustic approach that can detect changes in corn stover moisture content and shows the capability to propagate through corn stover and improve the moisture sensing range and accuracy as compared to currently available technologies. Using air-coupled transducers that operate at 20 kHz and a simple experimental setup, we determine the sound speed in corn stover. Signal analysis using cross-correlation and fast Fourier transform allows the calculation of sound speed and signal amplitude from the A-scan. An inverse relationship between the sound speed and the packing density of corn stover is found. Sound speed and transmission amplitude data enable the determination of corn stover’s moisture content between 10i% and 55%. The benefit of this technology also lies in its ability to sense through the center of a packed sample of corn stover at a density above 300 kg/m3. The improvement promises a decrease in the cost of handling and processing, which will help establish corn stover as an economically-viable bioenergy feedstock.

Shock-compressed silicon: Hugoniot and sound speed up to 2100 GPa

High-pressure equation of state and isentropic sound speed data for fluid silicon to pressures of 2100 GPa (21 Mbar) are reported. Principal Hugoniot measurements were performed using impedance matching techniques with \ensuremath{\alpha}-quartz as the reference. Sound speeds were determined by time correlating imposed shock-velocity perturbations in both the sample (Si) and reference material (\ensuremath{\alpha}-quartz). A change in shock velocity versus particle velocity (${u}_{s}--{u}_{p}$) slope on the fluid silicon principal Hugoniot is observed at 200 GPa. Density functional theory based quantum molecular dynamics simulations suggest that both an increase in ionic coordination and a 50% increase in average ionization are coincident with this experimentally observed change in slope.

Modeling and Determining the Averaged Binary Potential Fields of Five Noble Gases from Sound Speed

In terms of averaged interactive fields, this research discovered a new relation between averaged binary potential field (ABPF) and sound speed. Then, the ABPFs of five noble gases were modeled using an extended Lennard–Jones potential function. The derived equation based on the ABPF and the model potential accurately described the sound speed data of the five noble gases from the National Institute of Standards and Technology. Later, the surface of the ABPF was determined from the data, which indicated that the ABPF principally exhibited the conventional Lennard–Jones’ potential at low temperatures, but performed as a soft sphere potential at high temperatures. This temperature-based shift represents new knowledge regarding intermolecular interactions. The derived equation also provided a novel and practical method to calculate the sound speed from temperature and density.

Volumetric and Acoustic Properties of D(+) Glucosamine·HCl and L-Lysine·HCl in Aqueous Solutions at Different Temperatures

In present work, density and speed of sound of aqueous binary mixtures of biologically important amino acid derivatives namely D(+) glucosamine·HCl and L-lysine·HCl have been measured at three different temperatures i.e. (278.15, 288.15 and 298.15) K and in the concentration range of 0.0-0.2 mol kg-1. Using density and speed of sound data, different thermodynamic and acoustic parameters like apparent molar volume (Vφ) and apparent molar isentropic compression (Kφ) of solute have been computed at different temperatures. Speed of sound data have also been used to calculate hydration number (nH) of solute. The temperature dependence of the limiting apparent molar volume of solute has been used to calculate thermal expansion coefficient (α*), apparent molar expansivity (E0 φ) of solute and Hepler’s constant (∂2V0 φ/∂T2). The final outcome of the study has been discussed in terms of various interactions among solute and solvent molecules.

Investigation on stability, density and viscosity of ZnO/PEG nanofluids in the presence of 1-butyl 3-methylimidazolium chloride and 1-butyl 3-methylimidazolium bromide ionic liquids

Addition of ionic liquids (ILs) into the fluids containing nanoparticles is often used to minimize particle aggregation and improve dispersion behavior of nanofluids. However, they also affect the physical characteristics of liquids, such as thermophysical properties and viscosity. The aim of this work was to investigate the role of 1-butyl 3-methylimidazolium bromide [C4mim][Br] and 1-butyl 3-methylimidazolium chloride [C4mim][Cl] on the dispersion stability, volumetric characterizations and viscosity of polyethylene glycol 200 (PEG 200) nanofluids containing ZnO nanoparticles. Particle size distribution of these nanofluids has been studied by UV–Vis spectroscopy and dynamic light scattering (DLS). The obtained results show that the nanofluids with PEG 200 + [C4mim][Cl] have lower stability than PEG 200 + [C4mim][Br]. Additionally, in order to understand molecular interactions between components of studied nanofluids (ZnO, PEG 200 and ILs) the density (d), speed of sound (u) and viscosity ( $$\eta$$ ) of these nanofluids were measured at 293.15, 298.15, 308.15 and 308.15 K. The excess molar volume ( $$V_{m}^{E}$$ ), apparent molar volume ( $$V_{\phi }$$ ) and isentropic compressibility ( $$\kappa_{s}$$ ) have been calculated using density and speed of sound data. These properties can help us to discuss about the stability and volumetric characterizations of the nanofluids. Also, theoretical analyses of $$V_{m}^{E}$$ , $$\kappa_{s}$$ and $$\eta$$ were performed using some existing models (Ott et al., Redlich–Kister, Eyring-mNRF and Eyring-NRTL) and the obtained results were compared with experimental data.

Evaluation and Comparative Study of Acoustic Non-Linearity Parameter of Liquid Metals and Alloys using Sound Speed and Density Data

The non-linearity acoustic parameter (B/A) has been computed for six pure liquid metal alloys (Na, K, Rb, Cs, Pb and Sn), four liquid metal alloys (K-Rb, Na-Cs, Pb-Sn and Na-K) and other several liquid metals at different temperatures. This parameter has been calculated by using three different approaches viz. Hartmann method, Ballou rule and Johnson et al. method. The input data required density, sound speed and thermal expansivity were taken from literature. A comparative study has been carried out and quite satisfactory results are obtained.

Volumetric, acoustic, transport and FTIR studies of binary di-butylamine + isomeric butanol mixtures as potential CO2 absorbents

Due to application of dibutylamine as absorbent for CO2, densities (ρ), speed of sound (u) and viscosities (η) of binary liquid mixtures containing di-butylamine (DBA) + 1-butanol or + 2-butanol or + 2-methylpropan-1-ol or + 2-methylpropan-2-ol were determined in the temperature range 298.15 to 308.15 K as a function of mole fraction of DBA. Experimental data were used to calculate excess molar volume,VmE, deviation in speed of sound, Δu, excess isentropic compressibility, κSE, deviation in viscosities, Δη. These calculated properties were correlated by Redlich-Kister polynomial equation. Negative sign of VmEand κSE indicated the formation of strong associative interactions between unlike components, DBA and isomeric butanols. Negative values of Δη also is in support with the analysis made on the basis of VmEand κSE. VmEand κSEdata were analyzed theoretically in terms of PFP and Graph theoretical approach. Both theories predict sign as well as magnitude and both the theoretical results well supported the experimental data. The speeds of sound data were examined in terms of free length theory and various related correlations like Nomoto, van Dael, Impedance and collision factor theory (CFT). Δη values were analyzed in terms of Bloomfield and Devan's (BFD) model and theoretical results assisted the experimental results.

Speeds of Sound in n-Hexane and n-Heptane at Temperatures from (233.33 to 353.21)\xa0K and Pressures up to 20\xa0MPa

The speed of sound in high-purity n-hexane and n-heptane was experimentally studied utilizing the double-path length pulse-echo technique. Measurements with each alkane were carried out at temperatures from (233 to 353) K with pressures up to 20 MPa. Considering the uncertainty contributions from temperature, pressure, path-length calibration, pulse timing and sample purity, the relative expanded combined uncertainty (k = 2) in the speed of sound in n-hexane ranges from (0.012 to 0.042) % over the investigated ranges of pressure and temperature; for n-heptane, the uncertainty varies from (0.014 to 0.018) %. The sound speed data measured in n-hexane were among the data used for the development of a new fundamental equation of state, which is, however, not described in this work. The experimental data of n-heptane can be considered appropriate for modeling purposes and validation of existing equations of state.

Topological investigation of intermolecular interactions in di-isopropylamine (DIPA) + isomeric butanol mixtures: Volumetric and acoustic properties

This paper reports the density (ρ) and speed of sound (u) data of the binary DIPA+ isomeric butanol mixtures at the temperatures 298.15, 308.15 and 318.15 K. The excess molar volume, VmE, deviation in speed of sound, Δu, and excess isentropic compressibility, κSE, were calculated from the measured data. The excess properties were fitted to Redlich-Kister polynomial equation. VmE values were further analyzed in terms of Prigogine-Flory-Patterson (PFP) theory and Graph theoretical approach. The intermolecular interactions recognized by Graph theoretical approach were also confirmed by IR studies of the present binary mixtures. The speed of sound data were analyzed by Jacobson's free length theory and also predicted by various correlations.

Molecular interactions of l-glutamic acid and l-aspartic acid in aqueous solutions 1-heptyl-3-methyl imidazolium tetrafluoroborate [C7mim][BF4] at different temperatures

To study the molecular interactions between the ternary mixtures containing 1-heptyl-3-methyl imidazolium tetrafluoroborate [C7mim][BF4] as a common solvent with l-glutamic acid and l-aspartic acid respectively, densities and speed of sound have been measured at three different temperatures viz. T = 288.15 K, 298.15 K and 308.15 K under 0.1 MPa Pressure. The density and speed of sound data have been further utilized to calculate apparent molar volume and apparent molar isentropic compression. From the apparent molar volume and apparent molar isentropic compression, both properties at infinite dilution i.e. Vϕ0 and Kϕ,S0 have also been computed. To draw the conclusion from the volumetric and acoustic data, limiting apparent molar expansion Eϕ0, as well as hydration numbers, nH have been studied. It is quite worthwhile to study all of these derived or calculated parameters to perceive the solvation behavior, mixing aspects and various types of interactions born in the ternary solutions of (amino acid + [C7mim][BF4] + water) due to change in structure.

On the potential and challenges of laser-induced thermal acoustics for experimental investigation of macroscopic fluid phenomena

Mixing and evaporation processes play an important role in fluid injection and disintegration. Laser-induced thermal acoustics (LITA) also known as laser-induced grating spectroscopy (LIGS) is a promising four-wave mixing technique capable to acquire speed of sound and transport properties of fluids. Since the signal intensity scales with pressure, LITA is effective in high-pressure environments. By analysing the frequency of LITA signals using a direct Fourier analysis, speed of sound data can be directly determined using only geometrical parameters of the optical arrangement no equation of state or additional modelling is needed at this point. Furthermore, transport properties, like acoustic damping rate and thermal diffusivity, are acquired using an analytical expression for LITA signals with finite beam sizes. By combining both evaluations in one LITA signal, we can estimate mixing parameters, such as the mixture temperature and composition, using suitable models for speed of sound and the acquired transport properties. Finally, direct measurements of the acoustic damping rate can provide important insights on the physics of supercritical fluid behaviour.Graphic