Volume Research Articles

Study of non-ideality behavior in p-methyl acetophenone and 2-alkanol mixtures

In the current study, the density and viscosity of four binary fluids of p-methyl acetophenone with 2-propanol up to 2-hexanol systems at various temperatures (293.15 K, 303.15 K, 313.15 K, and 323.15 K) have been reported. Excess molar volume (VmE) and viscosity deviation (Δη) for the mixtures above were calculated. Negative values of VmE for all solutions were obtained. Also, values of viscosity deviations were negative for p-methyl acetophenone + 2-alkanol at all temperatures. Findings revealed that in the mixtures containing shorter alcohols, molecular interactions are stronger, and intermolecular forces reduce with the alcohol chain. Dipole-dipole interactions, the formation of hydrogen bonds between unlike molecules, and steric hindrances are the main intermolecular forces in the mixtures. Moreover, the PC-SAFT model was used to correlate the binary densities at different temperatures. Scientific papers have not yet reported the density and viscosity values of the mentioned fluids.

Investigation of ethanol-phenol interactions used in steam reforming process: Molecular level understanding through experimental and theoretical studies

Ethanol-phenol binary mixtures are used as feed for hydrogen production in the steam reforming process. The present work investigates the physicochemical properties of the various compositions of ethanol-phenol binary mixtures experimentally to understand the interactions of these two molecules at the molecular level. The densities (ρ) and sound velocities (U) values of the binary mixtures increased with the mole fraction of the phenol. The excess molar volume (VmE) and various acoustic parameters such as acoustic impedance (ZE), compressibility (βsE), and intermolecular free length (LfE) were computed in the whole mole fraction range. The negative values of VE, LfE, βsE and positive values of ZE, UE up to a 0.5 mole fraction of phenol indicate strong intermolecular interaction between dissimilar molecules than similar molecules. DFT/B3LYP computational methods were used to optimize the structure of the monomer of ethanol and phenol and the dimers, ethanol-ethanol, ethanol-phenol, and phenol-phenol with a 6-311G ++ (d, p) basis set. The variation of energy of all-possible conformers of homo and hetero molecular dimers of ethanol and phenol was computed by varying the distance between the molecules. The energy values obtained in the computational method supported the experimental findings well and envisaged the significant interaction between ethanol-phenol than ethanol-ethanol and phenol-phenol binary mixture at a 1:1 composition. Summarizing, the 1:1 stoichiometric ratio of the ethanol-phenol binary mixture could be the appropriate feedstock for optimal hydrogen production in the steam reforming process, and accordingly suitable substitute of this mixture can be designed to lessen the overload on ethanol-phenol mixture.

Determination of adsorption parameters in shale gas resource/reserve calculation: Case study of Wufeng Formation–Longmaxi Formation in the Sichuan Basin

In the calculation of shale gas resources/reserves, isothermal adsorption parameters are mainly determined by dry sample data at the laboratory temperature, and the regression effect of total organic carbon content (TOC) isothermal adsorption parameters is poor. Based on the physical significance of key parameters in Langmuir and Henry adsorption models, the problems in determining the isothermal adsorption parameters in the calculation of shale gas reserves/reserves are analyzed by taking the marine shale in the Upper Ordovician Wufeng Forming–Lower Silurian Longmaxi Formation in the Sichuan Basin as an example. Based on a large number of measured isothermal adsorption data, the effects of TOC, temperature and water saturation on the shale gas adsorption parameters are analyzed. The influence model of TOC, temperature and water saturation on isothermal adsorption parameters of shale gas is established, and a novel method for calculating the adsorption parameters of shale gas from under experimental conditions to original reservoir conditions is proposed. The results are obtained as follows. First, there are problems in the calculation of shale gas resources/reserves, such as poor and contradictory fitting relation between isothermal adsorption parameters and TOC, difficulty in the conversion of Van't Hoff equation, and difficulty in direct application of water saturation (Sw) in resource/reserves calculation. Second, the problem of poor direct fitting relation between Langmuir pressure (pL) and TOC is solved by integrating the Langmuir adsorption model with the Henry adsorption model and by establishing a new parameter – Henry constant a for methane adsorption capacity of shale. Third, when Sw<40%, the Langmuir volume (VL) is linearly negatively correlated with Sw; when Sw<20%, a is constant relatively; by establishing the relationship between the normalized absolute adsorption capacity and Sw (<50%) under the pressure exceeding 30 MPa, the effect of Sw on the isothermal adsorption capacity can be calculated. Fourth, the in-situ stress in the Wufeng Formation–Longmaxi Formation shale reservoir affects the adsorption capacity of shale. For shale reservoirs with the same TOC, the higher the in-situ stress, the smaller the VL and a values. Under high pressure (>30 MPa), the effect of Sw on the methane adsorption capacity of shale shows a similar trend, and the effect of water molecules on the adsorption capacity on shale pore surface is constant. It is concluded that the proposed novel method for determining the isothermal adsorption parameters of shale with different TOC, temperature and water saturation conditions provides a technical support for the accurate calculation of shale gas resources/reserves and contributes to the scientific development of shale gas industry.

Volumetric, Acoustic, and Refractive Behavior of Acid Gas Absorbers: N-Vinyl-2-pyrrolidinone and Glycol Ethers (2-(2-Ethoxyethoxy)ethanol, 2-(2-Butoxyethoxy)ethanol, and 2-(2-(2-Methoxyethoxy)ethoxy)ethanol)

Thermophysical properties such as density (ρ), speed of sound (u), and refractive index (nD) for pure N-vinyl-2-pyrrolidinone (NVP) and binary mixtures of NVP with 2-(2-ethoxyethoxy)ethanol (DEGMEE), 2-(2-butoxyethoxy)ethanol (DEGMBE), and 2-(2-(2-ethoxyethoxy)ethoxy)ethanol (TEGMME) have been measured over the whole range of mole fraction from temperature T = (298.15 to 323.15) K and at 0.1 MPa pressure employing an Anton Paar vibrating U-tube density and sound velocity meter (DSA 5000 M) and an Abbemat refractometer, respectively. To quantify the nonideality in these systems, the experimental data has been used to evaluate various acoustical and thermodynamic parameters, such as excess molar volume (VmE), deviation in the speed of sound (Δu), isentropic compressibility (κs), excess isentropic compressibility (κsE), deviation in refractive index (ΔnD), molar refraction (Rm), and polarizability (α). Molecular interactions prevailing in these systems have been explained in terms of variation in the measured and calculated values of physicochemical parameters. The collected thermophysical data can be employed in the optimization and design of a desulfurization/CO2-capture process utilizing the studied solutions. Furthermore, this data can also be utilized for the theoretical model extension as well as in solving many difficult engineering problems such as fluid flow, heat and mass transfer, and energy transformations.

Iris volume change with physiologic mydriasis to identify development of angle closure: the Zhongshan Angle Closure Prevention Trial

AimsTo assess dynamic change of iris area (Iarea) and volume (VOL) with physiologic pupil dilation for progression of primary angle closure suspects.MethodsParticipants underwent baseline examinations including gonioscopy and anterior segment...

Influence of alkyl chain length and temperature on the densities, viscosities and speeds of sound of binary liquid mixtures of {2-methyl-1-butanol + 2-ethoxyethanol, or 2-propoxyethanol, or 2-butoxyethanol} at T = (298.15, 303.15 and 308.15) K

Density (ρ), viscosity (η) and speed of sound (u) of pure components and binary mixtures of 2-methyl-1-butanol with alkoxyethanols viz., 2-ethoxyethanol, 2-propoxyethanol and 2-butoxyethanol have been measured over the entire range of composition at different temperatures T = (298.15, 303.15 and 308.15) K. Using the experimental data various thermophysical properties such as excess molar volume (VmE), excess molar isentropic compressibility (Ks,mE), excess speed of sound (uE), deviation in viscosity (Δη) and excess Gibb’s free energy of activation for viscous flow (ΔG∗E) have been calculated. The excess or deviation properties used to define the molecular interactions between like and unlike components. Further, the values of excess and deviation properties have been fitted to the Redlich-Kister polynomial equation. The measured viscosities have been correlated with various semi-empirical relations such as Grunberg-Nissan, Tamura-Kurata, Hind et al., Katti-Chaudhri, McAllister (three body interaction) model, Heric-Brewer and McAllister (four body interaction) model. Apart from this, Prigogine–Flory–Patterson (PFP) theory is also used for the estimation of VmE values for studied binary mixtures.

Full-scale pore characteristics in coal and their influence on the adsorption capacity of coalbed methane.

Coalbed methane (CBM) is primarily stored and transported through the pores in the coal matrix, making it essential to study the development of different scales of pores in coal to better understand the evaluation and exploration of CBM. In this study, four coal samples of varying ranks (Ro,max = 0.68%-2.86%) were selected, and different scale pores were obtained through low-pressure CO2 and Ar adsorption (LP-CO2/ArGA) and mercury intrusion porosimetry (MIP) experiments. A full-scale pore evaluation model was established, and the impact of pores on methane adsorption and restriction was analyzed and discussed through high-pressure adsorption experiments. Our results show that (1) at high pressures (> 100 MPa), the MIP technique caused pore compression and overestimated the pore size below 30 nm by up to 47.2%; (2) to obtain a comprehensive pore evaluation, we developed an accurate model that combines LP-CO2/ArGA with NLDFT and BJH and NLDFT models to determine micropore (0.3-1.5 nm) and mesopore (1.5-30 nm) parameters. By combining this model with MIP test results, we can obtain a full-scale pore size in the range of 0.3 nm-200 μm; (3) coal rank affected the development of full-scale pore characteristics. As coal rank increased, the specific surface area (SSA) of micropores and adsorption capacity of methane first decreased, then increased. Micropores were found to be the most important storage space for CBM and control gas adsorption, with a microporous SSA and PV to total SSA and total PV ratio of 97.93% and 63.69%, respectively. (4) We also observed a significant linear relationship between the fractal dimension of micropores and the Langmuir volume (VL) based on fractal theory. As the fractal dimension increased, VL also increased (R2 = 0.8581), indicating that VL is controlled by the complexity of micropores, which is consistent with the comprehensive evaluation index (Dt) and VL (R2 = 0.8744). Based on our predicted model, VL can be estimated using the SSA of micropores and Dt. Our findings shed light on the relationship between pore morphology and CBM occurrence and have practical implications for fields such as catalytic synthesis, E-CBM, and gas purification.

Excess properties, computational chemistry and spectroscopic analyses of 1,2-propanediamine + n-propanol/isopropanol binary mixtures

To understand excess properties and intermolecular interactions of 1,2-propanediamine and n-propanol/isopropanol binary mixtures, their density and viscosity were systemically measured at T = (298.15–318.15) K under atmospheric pressure (1005 hectopascals in Tianjin, China), and their excess molar volume (VmE), viscosity deviation (Δη) and excess viscous activation free energy (ΔG*E) were also calculated. From the results of VmE, it can be inferred that two n-propanol/isopropanol molecules and one 1,2-propanediamine molecule have the strongest binding capacity and form the most stable intermolecular hydrogen bonds. The experimental density and kinematic viscosity were correlated and predicted by several semi-empirical models, among which the Jouyban-Acree model had a better fit for the density and the McAllister four-body equation had a better fit for the kinematic viscosity, and the calculated results of VmE, Δη and ΔG*E were analyzed using the R-K equation. Meanwhile, the apparent molar volume, partial molar volume, thermal expansion coefficient and viscous activation parameters of 1,2-propanediamine and n-propanol/isopropanol solutions were calculated and analyzed. After that, the existence of intermolecular hydrogen bonds (IHBs) between 1,2-propanediamine and n-propanol/isopropanol binary mixtures was demonstrated on the basis of computational chemistry. And then, the IHBs between 1,2-propanediamine and n-propanol/isopropanol binary mixtures with the form of –OH···NH2– were further confirmed based on Raman, ultraviolet (UV), fluorescence (FLS) and nuclear magnetic resonance (1H NMR) spectral technologies.

Experimental, theoretical, computational and spectroscopic analysis in binary liquid mixtures containing 1-propanol and C-1 to C-4 alkyl acetates (T = 298.15–318.15 K): Physicochemical properties and molecular interaction studies

The molecular interactions between 1-propanol (1P) (1) and alkyl acetates (AAc) (C1-C4) (2) were examined by understanding of thermophysical properties of given binary liquid mixtures. Density (ρ), viscosity (η) and speed of sound (u) were measured for 1P, AAc and their binary mixture at T = 298.15–318.15 K with interval of 5 K at 0.1 MPa. Experimental data of ρ, η and u were used to evaluate VmE (excess molar volume), uE (excess ultrasonic speed), Δη (deviation in viscosity), ksE (excess molar isentropic compressibility), G∗E (excess Gibbs free energy of activation of viscous flow), VfE (excess free volume), LfE (excess intermolecular free length) and VaE (excess available volume) and correlated with R.K. (Redlich-Kister polynomial) equation. VmE data was also examined in term of Graph theoretical approach (GTA) and Prigogine-Flory-Patterson (PFP) theory. Δη were analyzed by Bloomfield and Dewan model (BFD) and also examined in terms of Graph theoretical approach (GTA). The u data was examined by different correlations like Van Dael, Nomoto, JFLT (Jacobson’s free length theory), Impedance dependence and CFT (Schaaff’s collision factor theory). FT-IR spectroscopic studies provide important information for understanding the intermolecular interactions between 1P (1) and AAc (2) components in the binary mixture which is also recognized by GTA. Further, DFT studies indicated the strength of molecular interactions and supported the graph theory in predicting probable associative molecular species in the liquid mixtures.

Multi-site comparison of clonal arrangements for tropical and subtropical hybrids of Eucalyptus

The definition of the ideal eucalyptus clonal arrangement directly affects the forest industrial chain, quality of products, and stand yield. The impact of eucalyptus in mono- versus multiclonal stands on plantation production and sustainability has been frequently discussed by primary stakeholders within the pulp industry, but few studies have examined this topic through direct comparison. In this study, we evaluated the differences in genotype ranking and yield of Eucalyptus spp. and clones displayed in mono- and multiclonal arrangements. In this context, the objectives addressed were: (i) to estimate genetic parameters in multi-environment and site-by-site analyses; (ii) to predict genotypic values of clones and the effects of species in mono- and multiclonal experiments, and (iii) to compare the similarity between the ranks of clones and species in the two types of clonal stands. The study was conducted in 2018 at four different sites of the CMPC Celulose Riograndense company, located in the state of Rio Grande do Sul, Brazil. Mono- and multiclonal arrangements were tested at each site, involving 33 eucalyptus clones belonging to 10 species and hybrids. Multiple-tree-plot (MTP) and single-tree-plot (STP) experiments were used to simulate monoclonal stands and multiclonal or composite stands, respectively. In each experiment, a randomized block design was set with three repetitions, 16 plants per plot for MTP, and 24 repetitions and one plant per plot for STP. Traits monitored were diameter at breast height (DBH), total height (H), tree volume (VOL), mean annual volume increment (MAI), and survival (SUV). Data were analyzed using mixed model approaches, considering a normal distribution for growth traits and a binomial family for survival. There was a strong genotype × site interaction for all traits, indicating that edaphoclimatic conditions must be considered for the successful establishment of clonal composites of differing genotypes. There was high similarity in the classification of clones in both mono- and multiclonal experiments, with genetic correlation values above 0.90. The performance of clones differed in mono- and multiclonal experiments, which correlated with their competition behavior toward each other (aggressive, suppressed, or homeostatic). Thus, clonal composites can be recommended based on clonal competition and genetic heterogeneity to maximize the yield of the stand and safeguard the plantations from biotic and abiotic disturbances. This study allowed us to identify the differences between the two types of commercial stands and provide direction for future research regarding the performance of Eucalyptus spp. in differing clonal arrangements. Novel information about competition categories for different eucalyptus tropical and subtropical species were provided.

Densities and Viscosities for the Ternary Mixtures of n-Undecane (1) + Butylcyclohexane (2) + 1-Pentanol (3) and Corresponding Binaries at T = (293.15 to 333.15) K

The actual composition is known to be highly responsible for the physical and chemical properties of a fuel. To understand the foundational physical properties of an aviation kerosene substitute mixture for hypersonic aircraft, n-undecane, butylcyclohexane, and 1-pentanol were used to construct a ternary system. The values of density (ρ) and viscosity (η) for the ternary system and three corresponding binaries were measured at temperatures T = (293.15 to 333.15) K and pressure p = 0.1 MPa. The Redlich–Kister equation was used to fit the excess molar volumes (VmE) and viscosity deviations (Δη) of the binary systems, while those of the ternary system were correlated with four semi-empirical formulas (Cibulka, Singh, Redlich–Kister, and Nagata–Tamura equations). The experimental results show that the VmE values of the three binary mixtures have a positive relationship with the mole fraction of nonpolar components, while Δη values have a negative relationship. The non-ideal behavior of mixtures is discussed from the perspective of molecular interactions and structural effects. This work provides data support and guidance for fuel compatibility research.

Multi-scale pore fractal characteristics of differently ranked coal and its impact on gas adsorption

Well-developed pores and cracks in coal reservoirs are the main venues for gas storage and migration. To investigate the multi-scale pore fractal characteristics, six coal samples of different rankings were studied using high-pressure mercury injection (HPMI), low-pressure nitrogen adsorption (LPGA-N2), and scanning electron microscopy (SEM) test methods. Based on the Frankel, Halsey and Hill (FHH) fractal theory, the Menger sponge model, Pores and Cracks Analysis System (PCAS), pore volume complexity (Dv), coal surface irregularity (Ds) and pore distribution heterogeneity (Dp) were studied and evaluated, respectively. The effect of three fractal dimensions on the gas adsorption ability was also analyzed with high-pressure isothermal gas adsorption experiments. Results show that pore structures within these coal samples have obvious fractal characteristics. A noticeable segmentation effect appears in the Dv1 and Dv2 fitting process, with the boundary size ranging from 36.00 to 182.95 nm, which helps differentiate diffusion pores and seepage fractures. The D values show an asymmetric U-shaped trend as the coal metamorphism increases, demonstrating that coalification greatly affects the pore fractal dimensions. The three fractal dimensions can characterize the difference in coal microstructure and reflect their influence on gas adsorption ability. Langmuir volume (VL) has an evident and positive correlation with Ds values, whereas Langmuir pressure (PL) is mainly affected by the combined action of Dv and Dp. This study will provide valuable knowledge for the appraisal of coal seam gas reservoirs of differently ranked coals.

Morphological and physiological traits of the respiratory system in Iguana iguana and other non-avian reptiles

Functional morphology considers form and function to be intrinsically related. To understand organismal functions, a detailed knowledge of morphological and physiological traits is necessary. Regarding the respiratory system, the combined knowledge about pulmonary morphology and respiratory physiology is fundamental to understand how animals exchange gases and regulate critical functions to sustain metabolic activity. In the present study, the paucicameral lungs of Iguana iguana were analyzed morphometrically through stereological analysis using light and transmission electron images and compared with unicameral and multicameral lungs of six other non-avian reptiles. The morphological data were combined with physiological information to perform a principal component analysis (PCA) and phylogenetic tests of the relationship of the respiratory system. Iguana iguana, Lacerta viridis, and Salvator merianae presented similar pulmonary morphologies and physiologies when compared to Varanus examthematicus, Gekko gecko, Trachemys scripta, and Crocodylus niloticus. The former species showed an elevated respiratory surface area (%AR), a high diffusion capacity, a low volume of total parenchyma (VP), a low percentage of parenchyma concerning the lung volume (VL), and a higher surface/volume ratio of the parenchyma (SAR/VP), with high respiratory frequency (fR) and consequently total ventilation. The total parenchymal surface area (SA), effective parenchymal surface-to-volume ratio (SAR/VP), respiratory surface area (SAR), and anatomical diffusion factor (ADF) showed a phylogenetic signal, evidence that the morphological traits are more strongly correlated with the species' phylogeny than the physiological traits. In sum, our results indicated that the pulmonary morphology is intrinsically related to physiological traits of the respiratory system. Furthermore, phylogenetic signal tests also indicate that morphological traits are more likely to be evolutionary conserved than physiological traits, suggesting that evolutive physiological adaptations in the respiratory system could happen faster than morphological changes.

Intra- and Inter-molecular Interactions between 1-Alkanol and Benzonitrile: Computational and Thermodynamic Study

This study presents an investigation on the intra- and inter-molecular interactions of binary systems composed of benzonitrile (BN) and 1-alkanols, namely, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-heptanol. For this purpose, from the experimental density (ρ) and speed of sound (u) data, excess volume (VE), isentropic compressibility (κs), and excess isentropic compressibility (ksE) were calculated for all binary liquid mixtures at different temperatures from (293.15 to 323.15) K with an interval of 5 K and at 0.1 MPa. Then, the calculated excess properties data have been correlated with the Redlich–Kister polynomial equation satisfactorily. Moreover, the interaction energies, bond characteristics, optimized geometries, and natural bond orbital (NBO) were theoretically calculated using the DFT-B3LYP method with 6-31G (d,p) basis sets for pure components and their complexes.

Thermodynamics of bicyclic compound + n-alkane mixtures

Mixtures formed by a cyclic molecule A, namely cyclohexane, or benzene, or bicyclohexyl ((1,1′-bi(cyclohexane)), or cis-decalin (cis-bicyclo[4.4.0]decane), or trans-decalin (trans-bicyclo[4.4.0]decane), or cyclohexylbenzene, or tetralin (1,2,3,4-tetrahydronaphthalene) and a n-alkane have been investigated by means of excess molar functions, enthalpies (HmE) and volumes (VmE), available in the literature, and of isochoric excess properties determined in this work, internal energies (UVmE) and heat capacities (CVmE). The behaviour of the systems with respect to the GmE(excess molar Gibbs energy) vs. HmE is discussed. The mixtures have been also studied using the zeroth approximation of DISQUAC and the Flory model. Dispersive interactions are dominant in the considered systems. The HmE values increase with n, the number of C atoms in the n-alkane, along each homologous series. Mixtures containing shorter n-alkanes and a bicyclic compound are characterized by large negative VmE values, which remark the existence of large structural effects. It is shown that longer n-alkanes are poorer breakers of the A-A interactions, which leads to decreased values of UVmE when n increases in systems with a given cyclic compound. The disruption of the short orientational order of longer n-alkanes by the A molecules lead to increased values ofUVmE. This effect is predominant in systems with cyclohexane, or benzene from n = 8, and UVmE decreases up to this alkane and then increases. However, the mentioned effect seems to be only predominant in systems with a bicyclic compound for n = 16. Thus, UVmE decreases up to n = 12 and increases for n = 16. The different behaviour of the treated systems is described by the Flory model through a X12 parameter which increases with n in solutions with cyclohexane or benzene, and that changes similarly to UVmE in the remainder solutions. In terms of DISQUAC, the enthalpic interaction parameter for the aromatic/aliphatic contact is independent of the n-alkane in systems with tetralin. For solutions with bicyclohexyl or cis-decalin, the variation with n of the mentioned parameter for the aliphatic/cyclic contact is similar to that observed for cyclohexane systems.

Density and Dynamic Viscosity of Perfluorodecalin-Added n-Hexane Mixtures: Deciphering the Role of Fluorous Liquids

Fluorous solvents are deputed as prominent solvent systems owing to their salient features, unique physical properties, and ecological importance. In this study, the temperature- and composition-dependence of physical properties, density (ρ/g·cm−3), and dynamic viscosity (η/mPa·s), of neat perfluorodecalin (PFD) and PFD-added n-hexane mixtures with select compositions are reported. Density follows a linear decrease with temperature and a quadratic increase with the mole fraction of PFD. The sensitivity or dependence of density on temperature increases with an increase in PFD mole fraction. The temperature-dependence of the dynamic viscosity of the investigated mixtures follows the Arrhenius-type expression from which the resultant activation energy of the viscous flow (Ea,η) is determined. Interestingly, the composition-dependence of dynamic viscosity shows exponential growth with an increase in PFD mole fraction. Excess molar volumes (VE) and deviation in the logarithmic viscosities ∆(ln η) of the mixtures are calculated to highlight the presence of strong repulsive interactions between the two mixture components.

Volumetric properties of binary liquid mixture of cyclopentyl methyl ether with 1-pentanol at 298.15 k temperature

The densities (ρ) and ultrasonic speeds (u) of Cyclopentyl methyl ether, 1- Pentanol and their binary mixture with the whole composition range have been measured at 298.15 K. From the experimental data the excess molar volume (VE), deviations in isentropic compressibility (∆ks), deviations in ultrasonic speed (∆u), deviations in acoustic impedance (∆Z) have been determined. The sign and magnitude of these parameters were found to be sensitive towards interactions prevailing in the studied system. Moreover, VE values were theoretically predicted by using Flory’s statistical theory. The variations of derived parameters mentioned above with composition offer a convenient method to study the nature and extent of interactions between the component molecules of the liquid mixture not easily obtained by other means.

Volumetric properties of ternary mixtures of N, N, N', N'-tetramethylethylenediamine/pentamethyldiethylene triamine + acetonitrile + H2O from (288.15 to 323.15) K

The densities of two ternary mixtures, N, N, N', N'-tetramethylethylenediamine (TMEDA) + acetonitrile (ACN) + H2O and pentamethyldiethylenetriamine (PMDETA) + ACN + H2O, and the corresponding binary mixtures TMEDA + ACN, PMDETA + ACN, TMEDA + H2O, PMDETA + H2O and ACN + H2O, were measured at different temperatures and 0.1 MPa. The studied temperatures are T = (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K. From the experimental data, excess molar volume (VmE), apparent molar volume (Vφ), partial molar volume (V¯) and excess partial molar volume (V¯E), were calculated. Furthermore, the VmE values for the binary mixtures were fitted to the Redlich-Kister polynomial equation. For the ternary systems, the VmE values were fitted to Nagata-Tamura equation and the fitting results were compared with those by Cibulka, Singh and Redlich-Kister equations. All the results were analyzed from the intermolecular interactions and molecular structure.

Thermodynamic properties of binary liquid mixtures of benzyl alcohol with 2-Alkoxyethanols at varying temperatures

In the present research, density (ρ) and speed of sound (u) for binary liquid mixtures of the benzyl alcohol (BA) with three 2-alkoxyalcohols {2-methoxyethanol (2-ME), 2-ethoxyethanol (2-EE), and 2-butoxyethanol (2-BE)} at temperatures of 298.15, 303,15 and 308.15 K have been measured over complete concentration of benzyl alcohol under 0.1 MPa pressure. According to measured results, excess molar volume (VmE) and deviation in isentropic compressibility (Δκs) were computed and these observed results were correlated to Redlich−Kister (R-K) polynomial expansion. Further, molar volume (Vm), apparent molar volumes (Vm,∅,1 and Vm,∅,2), acoustic impedance (Z), isentropic compressibility (ks), intermolecular free length (Lf), deviation in intermolecular free length (ΔLf) were calculated at all worked temperatures. For all studied systems, excess molar volume (VmE) and deviation in isentropic compressibility (Δκs), and deviation in intermolecular free length (ΔLf) were negative over the entire mole fraction range of benzyl alcohol at all measured temperatures. Among the three systems, benzyl alcohol with 2-ethoxyethanol containing system showed more negative. By using the obtained results, intermolecular interactions were discussed between benzyl alcohol and 2-alkoxyethanols. Moreover, the influence of temperature on intermolecular interactions was analyzed using above said parameters.

Thermodynamic properties of ketone with 2-methyl-1-butanol/2-ethyl-1-butanol at various temperatures

PurposeThe paper aims to throw light on the interactions taking place between the different chemical compositions at various temperatures. P-methylacetophenone is a polar dissolvable, which is positively related by dipole–dipole co-operations and is exceptionally compelling a direct result of the shortfall of any critical primary impacts because of the absence of hydrogen bonds; hence, it might work an enormous dipole moment (μ = 3.62 D). Alcohols additionally assume a significant part in industries and research facilities as reagents and pull in incredible consideration as helpful solvents in the green innovation. They are utilized as pressure-driven liquids in drugs, beauty care products, aromas, paints removers, flavors, dye stuffs and as a germ-free specialist.Design/methodology/approachMixtures were prepared by mass in airtight ground stopper bottles. The mass measurements were performed on a digital electronic balance (Mettler Toledo AB135, Switzerland) with an uncertainty of ±0.0001 g. The uncertainty in mole fraction was thus estimated to be less than ±0.0001. The densities of pure liquids and their mixtures were determined using a density meter (DDH-2911, Rudolph Research Analytical). The instrument was calibrated frequently using deionized doubly distilled water and dry air. The estimated uncertainty associated with density measurements is ±0.0003 g.cm−3. Viscosities of the pure liquids and their mixtures were determined by using Ostwald’s viscometer. The viscometer was calibrated at each required temperature using doubly distilled water. The viscometer was cleaned, dried and is filled with the sample liquid in a bulb having capacity of 10 ml. The viscometer was then kept in a transparent walled water bath with a thermal stability of ±0.01K for about 20 min to obtain thermal equilibrium. An electronic digital stop watch with an uncertainty of ±0.01 s was used for the flow time measurements for each sample at least four readings were taken and then the average of these was taken.FindingsNegative values of excess molar volume, excess isentropic compressibility and positive values of deviation in viscosity including excess Gibbs energy of activation of viscous flow at different temperatures (303.15, 308.15 and 313.15 K) may be attribution to the specific intermolecular interactions through the hetero-association interaction between the components of the mixtures, resulting in the formation of associated complexes through hydrogen bond interactions.Originality/valueThe excess molar volume (VE) values were analyzed with the Prigogine–Flory–Patterson theory, which demonstrated that the free volume contribution is the one of the factors influencing negative values of excess molar quantities. The Jouyban–Acree model was used to correlate the experimental values of density, speed of sound and viscosity.