Values Of Molar Volume Research Articles

Oxide ion polarizabilities and gamma radiation shielding features of TeO2–B2O3–SiO2 glasses containing Bi2O3 using Phy-X/PSD software

A system of lead-free silica borotellurite glasses containing bismuth oxide was fabricated in accordance with conventional melt-quenching procedure. XRD analysis, UV-Vis spectroscopy and Archimedes principle were employed to unveil the structural, and optical properties. User friendly Phy-X/PSD software was used to ascertain the theoretically radiation shielding features of the glasses. The existence of a diffuse hump in the XRD profile revealed the glasses amorphous characteristic. The molar volume and density values showed nonlinear variation with respect to the increase in mol% of Bi2O3. Optical bandgap, index of refraction, oxide ion polarizability (based on index of refraction and bandgap), optical dielectric constant, and third order susceptibility were computed. Various shielding related parameters, specifically, mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), effective atomic number (Zeff), effective electron density (Neff), mean free path (MFP), half value layer (HVL) and tenth value layer (TVL) were evaluated in the gamma photon energy range between 0.015 MeV and 15 MeV. The results revealed that BSBT5 glass containing higher Bi2O3 mol% exhibits maximum values of density, MAC, LAC, Zeff, Neff and minimum MFP, HVL and TVL. This indicates enhancement in the glass shielding properties with the addition of bismuth and the superiority of BSBT5 glass for radiation shielding applications compared to other studied glasses.

Effect of lanthanum oxide addition on physical, electrical and dielectric properties in lithium borosilicate glasses

In the present study, lanthanum oxide doped lithium borosilicate glasses were synthesized using standard melt-quenching technique. The synthesized glass materials were characterized by XRD, FTIR, density calculation, Electrical and dielectric properties measurements. The amorphous nature of the studied glasses was established through XRD spectra. FTIR spectra were used to investigate the different functional groups. Improvements in density and molar volume values were reported as the La2O3 content increased, it can be attributed to higher molecular weight of La2O3. Numerous other physical parameters such as lanthanum ion concentration (N), inter-nuclear distance (ri), polaron radius (rp), and field intensity (F) were determined using density values and are discussed in detail here. Electrical conductivity and dielectric measurements were carried out by impedance spectroscopy. The dynamical processes taking place in the glass system was studied by introducing conductivity and composition scaling. The dielectric constant (ε’) and dielectric loss (Tan δ) with frequency at various temperatures are extensively explored. There is a fairly good correlation among the physical parameters, FTIR, electrical conductivity and dielectric properties for the glasses studied in the present work.

Volumetric and acoustic properties of L-phenyl glycine and L-phenylalanine in aqueous solution of 1-dodecyl-3-methylimidazolium bromide [C12mim] [Br

To study the molecular interactions between the ternary mixtures containing long chain imidazolium based ionic liquid as a common solvent with substituted amino acids L-phenyl glycine and L-phenylalanine respectively, densities and speed of sound have been measured at three different temperatures viz. T = 288.15 K, 298.15 K, 318.15 and 318.15 K under 0.1 MPa pressure. The density and speed of sound data have been further utilized to calculate the apparent molar volume and apparent molar isentropic compression. From the data obtained, apparent molar volume (Vϕ), partial molar volume (Vϕ0), and standard partial molar volumes of transfer (ΔVϕ0). Positive values of apparent molar volume indicate strong interactions. Also, partial molar isentropic compression of transfer (ΔKϕ,S0) and partial molar isentropic compression (Kϕ,s) have been calculated from the sound of speed. Furthermore, structure making and structure breaking ability of solute have been discussed by evaluation of apparent molar expansivity, (ϕE0), Hepler's constant values ∂/∂Tp. The obtained results have been discussed in terms of solvation behavior, structural changes and various interactions present in different ternary mixtures (1-dodecyl-3-methylimidazolium bromide + amino acids + water).

Physical, structural and gamma ray shielding behaviour of PbO-CuO-CaO-B2O3 glasses

The amorphous PbO-CuO-CaO-B2O3 glasses, fabricated using the melt quenching technique, were studied for their physical, structural and gamma ray shielding behaviour. The density of the glasses increases with PbO content. As ion concentration increases whereas the polaron radius and inter-nuclear distance decreases with lead content. Oxygen packing density and oxygen molar volume depends upon the density and molar volume values. The recorded FTIR spectra indicated the stretching and bending vibrations of the groups formed in the glasses. The transmission factor (TF) was calculated at 0.284 and 0.511 MeV and we found that for the glass with chemical composition 35PbO-35B2O3–15CuO–15CaO, the TF is 54% at a photon of 0.284 MeV, but this value increases to 77% when the photon has an energy of 0.511 MeV. Also, the radiation shielding results demonstrated that the radiation protection efficiency of glass is improved by adding PbO. From the tenth value layer TVL) results, we found that with increasing energy, the ratio TVLA1/TVLA4 decreases gradually, and this means that the effect of PbO is more pronounced at lower energies. At 0.284 MeV, the recorded ratio is 1.4, while this ratio decreases to 1.3 at an energy of 0.347 MeV and to 1.2 at an energy of 0.826 MeV. The results from this work reveal the importance of using a relatively high percentage of heavy metal oxides such as PbO in the manufacture of new and promising glass systems for use as alternative materials in radiation protection.

Density, speed of sound, and surface tension of binary aqueous solutions containing ammonium based protic ionic liquids

Density, ρ, speed of sound, u, and surface tension γ, of binary mixtures containing ethanolammonium based protic ionic liquids (PILs) and water were measured to access the influence of PIL-water interactions on physicochemical properties. Volumetric properties of PILs were evaluated at ambient pressure but at temperatures from 298.15 K to 313.15 K. Apparent molar volume and apparent molar isentropic compressibility values of ethanolammonium acetate [EAAc], ethanolammonium butanoate [EABu], and ethanolammonium hexanoate [EAHx], were calculated and commuted to determine the infinite dilution partial molar volume using Redlich-Mayer type of equation. Further, excess molar volume was also determined as a function of mole fraction. The coefficients of Redlich-Kister equation also determined and presented. Overall, the hydrophilic interactions occur between PILs and water molecules and the strength of interactions weakens as anionic chain length increases. Low surface tension values were observed for PILs with longest alkyl chain. The results indicate that hydrophobicity of alkyl chain strongly influences the interfacial properties.

Binary mixtures of {1-Ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][triflate]) + alcohols} at high-pressure: A thermodynamic, spectroscopic and correlation approach

The density of binary mixtures of {1-Ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][triflate]) + alcohols} has been measured at temperatures from (298.15 to 308.15) K and pressures from (0.1 to 40) MPa. The effect of temperature and pressure on density and calculated excess molar volumes, partial molar volumes, apparent molar volumes and partial molar volumes at infinite dilution was analyzed. The experimental density results were correlated by using the Tait-Tammann equation to deduce isothermal compressibility and isobaric expansivity. In addition to the thermodynamic study, some spectroscopic properties (H-NMR, C-NMR and FT-IR) were presented to elucidate some possible molecular interactions between the components under study. Furthermore, the Extended Real Associated Solution Model (ERAS Model) was applied to correlate the values of excess molar volume.

Optimization of Thermo-Physical Properties For The Binary System Of Acetone–Water At 303.15-318.15 K By Response Surface Quadratic Model

Thermo bodily residences of binary liquid combos are very beneficial in biotechnology, pharmaceutical, chemical and petroleum refining industries for improved favoured products from diverse raw materials. The physical property data on mixed solvents are important for the theoretical and applied areas of research and are frequently used in many chemical and industrial processes such as design of new process and process equipment (fluid flow, mass transfer or heat transfer calculation) and designing of bioreactor/fermenter. The objective of the current paper is to determine the density, viscosity, ultrasonic velocity, refractive index and surface tension of acetone (1) + water (2) at temperatures of 303.15K to 318.15K for the complete composition degrees and atmospheric pressure. These experimental values were used to calculate the respective excess homes in conjunction with a few acoustic properties. The experimental facts and excess residences have been used to calculate the interacting coefficients and well known deviations from different existing models. Also the new model equations have been evolved with the aid of the use of Design Expert application for density, viscosity, ultrasonic velocity, refractive indices and surface tension. Experimental consequences have been analysed on the premise of molecular interactions among element molecules with the assistance of FT-IR spectrum. Acetone-water binary structures of the prevailing observer have positive values of excess molar volumes and deviations in isentropic compressibility over whole composition range and at all temperatures which suggests sturdy interactions among the components of binary mixtures. Thermodynamic observations of acetone and water mixtures were made. Negative viscosity deviation of acetone-water combinations suggests robust dipole-dipole interactions within the device. Fourier remodel infrared spectroscopy also indicates the sturdy interaction made at 3589 cm-1 and based on the response surface method outcomes, more interplay takes area at zero. Five and zero six moles of acetone and water combination and the consequences are conformed with reference to the R2 cost (0.89). Excess molar extent and isentropic compressibility were decided and kinds of interactions have been discussed primarily based on the derived properties.

Density, speed of sound, refractive index and relative permittivity of methanol, propan-1-ol or pentan-1-ol + benzylamine liquid mixtures. Application of the Kirkwood-Fröhlich model

Densities (ρ), speeds of sound (c), relative permittivities at 1 MHz (εr) and refractive indices at the sodium D-line (nD) at T = (293.15 K to 303.15 K) and p = 0.1 MPa are reported for binary liquid mixtures alkan-1-ol + benzylamine. Methanol, propan-1-ol and pentan-1-ol are the alkan-1-ols studied in this work. The values of the excess molar volume (VmE), excess isentropic compressibility (κSE), excess speed of sound (cE), excess refractive index (nDE), excess relative permittivity (εrE) and its temperature derivative (∂εrE/∂T)p are calculated, and they are adjusted to Redlich-Kister polynomials. The VmE values are negative, indicating a predominance of the solvation between unlike molecules and structural effects. εrE values indicate a positive contribution from the creation of (alkan-1-ol)-benzylamine interactions, and the positive value for the methanol mixture emphasises the importance of solvation. Calculations on excess molar refractions point out to weaker dispersive interactions than in the ideal mixture, which may be explained by the mentioned solvation effects. The Kirkwood-Fröhlich model has been applied to the mixtures, and the Kirkwood correlation factors suggest an important relative weight, especially in the methanol system, of linear-like molecules in the solutions, which is in accordance with the positive contribution of the formed multimers to εrE due to their good effective response to the electric field.

Towards highly transparent tungsten zinc sodium borate glasses for radiation shielding purposes

The impact of tungsten oxide (WO3) additions on the structure, some physical and radiation shielding parameters of sodium zinc borate glasses have been scrutinized. These glasses were properly produced by the melt quenching method. The amorphous state was affirmed by X-ray diffraction (XRD) data. The internal structure within the short-range order of the glassy network was studied by the method of infrared spectroscopy (IR). The results of IR showed that the BO4 units are transformed to BO3 accompanied by the formation of nonbridging oxygens with further WO3 doping. This transformation of BO4 to BO3 and nonbridging oxygens is employed to explain the increase in the molar volume values with changing WO3/ZnO amount. Further, the optical transmittance was measured within the visible range to assure the transparency of the prepared glasses. The transmittance results confirm the absence of W5+, W4+, W3+ states; based on the absence of their absorption bands. Also, the transmittance results indicate that the only oxidation state in the present glasses is hexavalent tungsten (W6+). Additionally, the parameters of radiation protection of the manufactured glasses were investigated. It was found that, the addition of WO3 improves not only the radiation protection parameters (such as the linear attenuation coefficient) but also the transparency of the prepared glasses. Finally, we concluded that, the addition of WO3 to the glass samples leads to transparent glasses with an improved shielding ability at low energies but effects slightly at high energies. Due to the high transparency and the increased values of the linear attenuation coefficient of the prepared glasses, they are considered promising glasses in the field of nuclear radiation protection, especially at low energies.

Volumetric properties of binary mixtures of glycerol + alkanols (C1-C4): Experimental study and application of the Peng–Robinson–Stryjek–Vera equation of state

Volumetric properties for binary mixtures of (glycerol + methanol, or + ethanol, or + 1-propanol, or + 2-propanol, or + 1-butanol) have been determined as a function of composition using experimental data of density at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K and p = 92.3 kPa. The density measurements have been determined by using a vibrating-tube densimeter. The density values enabled the determination of the thermal expansion coefficient and the excess molar volume. The values of excess molar volume were correlated by a Redlich-Kister polynomial and by the Peng-Robinson-Stryjek-Vera equation of state (PRSV EOS). These values were also used in the estimation of the partial molar volumes, excess partial molar volumes and apparent molar volumes. Three different methods were used to determine the partial molar volumes at infinite dilution. For all studied systems, the values of excess molar volumes were negative over the entire composition range and suggest predominance of chemical and structural effects.

An improvement on Martin–Hou equation of state for more precise prediction in the liquid region

AbstractA modified Martin–Hou (M–H) equation of state (EOS) for the accurate representation of thermodynamic property data of some pure substances in liquid phase is presented in this work. The improvement is achieved by substituting a new parameter η into the original M–H EOS. Eighteen pure substances are chosen to construct the dependency relationship of η on reduced temperature Tr and acentric factor ω. Furthermore, to verify the effectiveness and improvement of the modified M–H EOS, the calculated values of the saturated vapor and liquid molar volumes are compared with the literature data in the reduced temperature ranging from approximately 0.6 to 1.0. The results show that the modified M–H EOS perform a good prediction in gaseous phase for pure substances with the average absolute deviation (AAD) generally less than 1%, and more precise liquid molar volume values can be obtained with the modified equation. In liquid phase, the AAD of the modified M–H EOS is 3.71%, which is much lower than 6.16% of the original M–H EOS.

Synthesis, physical, optical, structural and radiation shielding characterization of borate glasses: A focus on the role of SrO/Al2O3 substitution

In a bid to expand the amount of information available on glass systems and their potential applications for radiation shielding design, glass samples with the compositions (30-x)SrO-xAl 2 O 3 –68B 2 O 3 –2V 2 O 5 (x = 5, 7.5, 10, 12.5&15 mol %) coded as SABV0 - 4 were prepared by the melt-quenching technique and analyzed for their optical, structural, physical, and radiation shielding features. The glassy (amorphous) nature of the SABV glass samples was affirmed by broad peaks of X-ray diffraction spectra. Calculated values of density and molar volume shown opposite behavior and the variation of these values were discussed as structural modifications in the glass matrix. From recorded optical absorption spectra optical band gap energy (Eg)-indirect transition, Urbach energy and optical basicity were estimated. FTIR spectra were recorded for all the samples in the range 400 cm −1 to 4000 cm −1 . The FTIR absorbance spectra unveiled the SABV network structure mainly incorporating of BO 3 and BO 4 units. Raman spectroscopy is achieved to detect the structural changes and at higher wavenumber, B–O stretching modes in [BO 3 ] observed with one or two NBO's. The results of ESR spectra of glasses have indicated the highly covalent environment of vanadium ions. Analysis of the photon shielding parameters of the glasses which were obtained primarily from FLUKA Monte Carlo simulations and XCOM computations revealed photon energy and glass chemical composition dependence. The mass attenuation coefficient and effective atomic number ranged from 0.2668 to 0.3385 cm 2 g -1 and 12.98–15.93 accordingly as the weight fraction of Sr increased from 16.06 to 26.72% in the glasses. Generally, photon shielding ability of the SABV glasses follows the trend: SABV0 > SABV1 > SABV2 > SABV3 > SABV4. The thermal neutron total cross section follows the same trend with values fluctuating between 71.9553 and 80.6268 cm −1 . However, SABV1 showed superior fast neutron moderating capacity among the glasses. The present SABV glasses showed outstanding photon shielding ability compared to common shields. The prepared glasses are thus suitable candidates for radiation protection applications.

Volumetric properties, conductivity and computation analysis of selected imidazolium chloride ionic liquids in ethylene glycol

In this paper, the influence of the side chain length of five ionic liquids (ILs): 1-methylimidazolium chloride ([C0mim][Cl]), 1,3-dimethylimidazolium chloride (([C1mim][Cl]), 1-ethyl-3-methylimidazolium chloride (([C2mim][Cl]), 1-butyl-3-methylimidazolium chloride (([C4mim][Cl]) and 1-hexyl-3-methylimidazolium chloride (([C6mim][Cl]) on the interactions with ethylene glycol (EG) was studied. Based on the measurement of density and electrical conductivity of the ionic liquid + EG mixture in the temperature range (278.15–313.15) K, the values of apparent molar volume, standard partial molar volumes, apparent molar volume at infinite dilution, Masson’s interaction coefficient, thermal expansion coefficient, limiting apparent molar expansibilities, Heppler’s coefficient, ion association constants, thermodynamic parameters of ion-pair formation as well as diffusion coefficient was calculated. Experimental results were supported by molecular dynamic simulations. With the increase of the side chain length, from C0mim+ to C6mim+ cation, ion–dipole interactions on the solvation process decrease, and the influence of solvophobic solvation increases. Ionic liquids [C0mim][Cl] and [C1mim][Cl] show structure-breaker properties, [C4mim][Cl] and [C6mim][Cl] structure-making properties in EG solutions, while [C2mim][Cl] is borderline. The values of ion association constants in EG are higher than in water. The ion association process is spontaneous for all ionic liquids and entropy-driven.

Spectroscopic properties in simple cost glasses with alkaline oxides doped with Sm2O3 for display laser emission

This research investigates the influence of the concentration of Sm+3 ions on the properties of a new borosilicate glass system with the composition 50B2O3– 14SiO2- 20Li2O– 15Na2O– 1.0Al2O3-x(Sm2O3), where × = 100, 200, 300, 400, and 500 ppm. The glasses are characterized by XRD, FTIR, UV– Vis-NIR, and photoluminescence spectra. The XRD results proved that all glasses prepared are amorphous. Moreover, it was found that the values of density (ρ), and refractive index (n), rise with increasing of Sm+3 content. Otherwise, the value of molar volume, optical energy gap, and boron-boron distance decrease by increasing Sm+3 concentration. The structure of glasses studied was investigated by computing Internuclearri, Polaron radius rp, field strength F and the deconvolution of FTIR spectra. Judd-Ofelt theory was applied to clarify the structural changes and nature of the bonds of glasses prepared. Moreover, a spectroscopic quality factor, the branching ratio (βr), and lifetime (τ) are calculated with the use of Judd-Ofelt parameters. The color chromaticity of the glasses confirmed that the emission in the white-reddish orange region under 402 nm excitation is affected by the concentration of Sm3+ ions. The results of photoluminescence emission stimulated emission cross-section, and CIE chromaticity leads to the conclusion that the glass BSLNA5 are promising candidates as laser material for light-emitting diode (LED).

Density, viscosity, surface tension, excess properties and molecular interaction of diethylene glycol (1) + 1,2-propanediamine (2) at atmospheric pressure and T = 293.15 K ∼ 318.15 K

Under atmospheric pressure of the laboratory (88.94 KPa), the density (ρ), viscosity (η) and surface tension (γ) for binary mixture system of the diethylene glycol (DEG) (1) + 1,2-propanediamine (1,2-PDA) (2) were measured in different concentration ranges at T = 293.15 K ∼ 318.15 K. According to the basic data of ρ, η and γ, excess molar volumes values (VmE), viscosity deviation (Δη), surface tension deviation (Δγ), partial molar volume (V1¯ and V2¯), apparent molar volume (Vφ,1 and Vφ,2) and thermal expansion coeficiente (αρ) were calculated and fitted by Redlich-Kister (R-K) equation, the least square method and other formulas. At the same time, the interaction between DEG (1) + 1,2-PDA (2) was also discussed by Gaussian 09, Fourier Transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–vis), and Fluorescence spectroscopy (FLS) etc. The results were displayed that a hydrogen bond was formed between the nitrogen atom (N) on the amino group (–NH2) of 1,2-PDA and the hydrogen atom (H) on the hydroxyl group (–OH) of DEG, which took the form of HOCH2CH2OCH2CH2OH⋯NH2CH2CHNH2CH3.

Apparent molar volumes of ILs [EmimNTf2], [BmimNTf2], and [BmmimNTf2] in DEC and PEGMME solvents

Different groups have important influence on the interaction between molecules. In order to understand the effect of group introduction on the molecular interaction in solution, the densities of six diluted solutions including three ionic liquids (ILs) and two organic solvents were measured. The groups include methylene and methyl. The three ILs are 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][NTf2]), 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Bmim][NTf2]), and 1-butyl-2,3-dimethylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Bmmim][NTf2]). The organic solvents are diethyl carbonate (DEC) and propylene glycol monomethyl ether (PEGMME). The measured densities were used to calculate apparent molar volumes, Vϕ/cm3·mol-1, from 293.15 to 328.15 K with ± 0.02 K. Then, the fitting of infinite dilution apparent molar volumes, Vϕ0/cm3·mol-1, were obtained by using the calculated values of apparent molar volumes. The effects of different structures of ILs cations and organic solvents on the apparent molar volume, infinite dilution apparent molar volume, limiting apparent molar expansibility and thermal expansibility coefficient were discussed.

VOLUMETRIC AND VISCOMETRIC DETERMINATION OF BINARY LIQUID MIXTURES OF 2-ETHOXYETHANOL AND AMYL ACETATE AT TEMPERATURES OF (298.15 AND 303.15) K

Densities and viscosities have been determined at temperatures of (298.15 and 303.15) K for binary liquid mixtures of 2-ethoxyethanol with amyl acetate over the entire range of solvent composition. From the experimentally determined values, excess molar volume, VE, excess viscosity, ηE and excess Gibbs free energy of activation of viscous flow, G*E have been calculated. These calculated excess thermodynamic functions were fitted to Redlich-Kister polynomial equation to obtain the fitting coefficients and standard deviations. The values of excess molar volume, VE were negative and that of the excess viscosities, ηE were found to be positive, while excess Gibbs free energy of activation of viscous flow, ΔG*E were negative over the whole range of solvent composition for the binary systems at the studied temperatures. The behavior of these excess functions with composition of the mixtures have been discussed in respect of molecular interactions between the components of liquid systems. The mixture viscosities were correlated using empirical relations like Grunberg-Nissan, Frenkel, Hind, Wijk and Kendall-Monroe model equations. Comparison of these interaction parameters have been engaged to explain the intermolecular interactions between the alkoxy alcohol and the ester.

Influence of manganese ions on physical and spectroscopic properties of mixed alkali-alkaline earth oxide borate glasses

In this paper the studies on xMO-10Li2O-10Na2O–10K2O-(70-x)B2O3 [M=Mg, Sr and Ba] [x = 2, 4, 6, 8 and 10 mol%] glasses doped with manganese ions are reported. The physical and spectroscopic properties were investigated to know about the influence of the alkaline ions. The density values of all the glasses were found to increase with increasing alkaline earth oxide content while the values of molar volume were decreasing. The UV–VIS spectra of these glasses have shown single broad band which was assigned to the 6A1 g(S) → 4T1 g (G) transition. The non-linear variation of the optical band gap with the increase of alkaline earth oxides suggests non-linear variation in the number of non-bridging oxygens. The EPR spectra demonstrated a predominant sextet hyperfine structure located around g = 2.0 which were ascribed to the octahedral symmetric octahedral Mn2+ ions. From the hyperfine splitting parameters (Aavg), it was noticed that the environment around Mn2+ ions is ionic. The number of spins participated in resonance (N) and magnetic susceptibility (χ) values were evaluated taking the high field g-values (g ≈ 2.0). It is interesting to note that, the observed zero field splitted (ZFS) values (D) are varying non-linearly with the glass compositions and their values were increasing with the substitution of alkaline earth ions from Mg to Ba. The FTIR spectra of the glasses were analyzed in the range 400–2200 cm–1 to investigate the structural changes in the glass network.

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.

Adsorption properties of amino acid-based ionic liquids (AAILs) on edge fluorinated graphene surface – a DFT study

ABSTRACT We have investigated the adsorption properties of amino acid-based ionic liquids (AAILs) on edge fluorinated graphene surface (FG). Adsorption of organic ILs on the FG surface occurs via hydrogen bonds (X-H···FC), electrostatic interactions, and π···π interactions. There are large charge transfers between the interfaces, primarily from the lone pair of the fluorine (C-F bond) to the X-H (X = C, N, O) bond of both cations/anions AAILs. These non-conventional reversible hydrogen bridges are essential in surface interactions. However, substantial charge transfer occurs to cations and anions in both aromatic and aliphatic systems, respectively. Interestingly, aromatic AAILs are firmly physisorbed than aliphatic ILs. The inclusion of dispersion corrections increases the accuracy of total binding energy contributions from multiple adsorption interactions and predicts the complex's kinetic stability. Molar volume values determine the materiality of AAIL/FG to bulk systems.