Excess Volumes VE Research Articles

Effects of 2-Butanol Addition on Waste Cooking Oil Biodiesel Density: An Updated Experimental Measurement and Thermodynamic Modeling Study

Biodiesels will become the most popular alternative energy resource to fossil diesels; they can be used alone or blended with an oxygenated additive in any proportion. The properties of biodiesels strongly depend on the type of the fatty acid methyl esters (FAME) that compose them. The main objective of the present work is to investigate the influence of 2-butanol addition on the waste cooking oil biodiesel (WCOB), for this fact, the new experimental density data (952 points) of WCOB + 2-butanol binary mixtures over a wide range of composition [seven compositions; 0 ≤ (WCOB) mole fraction x ≤ 1] between 0.1 and 140 MPa and 298.15 and 393.15 K are presented. The experimental data were correlated using Tait and perturbed chain-statistical associating fluid theory (PC-SAFT) equations of state (EoS), to our knowledge, this is the first time that density measurements for the WCOB + 2-butanol mixture are correlated using the famous PC-SAFT EoS. The Tait equation predicts successfully the density with a global absolute average deviation (AAD) of 0.089%, while the PC-SAFT model correlates well the density with a very small global AAD of 0.223% in each composition. Furthermore, contrary to the Tait equation, the PC-SAFT model can explain some interactions between fluid molecules. From the experimental data, the excess volumes VE have been calculated and fitted using the Redlich-Kister equation with a very small global standard deviation of 7.49 × 10-5 cm3 mol-1, and VE show a positive and symmetric parabolic shape in all composition ranges. Finally, the isobaric thermal expansivity, αp, and the isothermal compressibility, κT, have been derived from the Tait equation and their observed trend was as expected.

Molecular dynamics simulations of aqueous solutions of short chain alcohols. Excess properties and the temperature of maximum density

The excess enthalpy hE and excess volume vE of the binary systems {methanol, ethanol, 1-propanol, 2-propanol, and tert-butanol + water} over the whole composition range at 298.15 K and the temperature of maximum density, TMD, in the alcohol diluted region were studied by MD simulations at atmospheric pressure. Our model systems were defined using the flexible version of the TIP4P/2005 model of water, the OPLS-AA for alcohols, and the geometric combining rule for all the Lennard-Jones cross interactions, with the exception of those between oxygen sites of water and alcohol molecules. These latter values were fitted to reproduce the experimental excess properties of the mixtures. This new parameterization allows for an appropriate description of the excess thermodynamics of these short-chain alcohol/water systems over the whole composition range. The changes in the temperature of maximum density of water induced by the addition of small amounts of alcohol concentration are, however, not adequately reproduced by our models. In all instances we observe a pronounced decrease of the simulated TMDs when alcohol concentration increases. This is in sharp contrast with the experimental behavior, which at very high dilution displays slight increases in the TMD right before the decreasing regime sets in for higher alcohol concentrations. For similar alcohol mole fractions, the simulated decrease of the TMDs grows in parallel with the size of the alkyl group of the alcohol. A similar situation is found experimentally for concentrations higher than those that increase the TMD. These differences disappear when the TMD change is expressed in terms of the mass concentration of alcohol. This leads to very similar Despretz constants for all solutions studied in this work.

Excess Volume, Viscosity, and Isentropic Compressibility of Methyl Acrylate + Alkane Binary Mixtures

This paper reports experimental data on densities (ρ), viscosities (η), and ultrasonic velocities (u) of four binary mixtures of methyl acrylate with heptane, decane, dodecane, and tridecane at temperatures of 303.15, 308.15, and 313.15 K and atmospheric pressure. The excess or deviation parameters such as excess volume VE, deviation in viscosity Δη, and excess isentropic compressibility KSE are evaluated and interpreted in terms of molecular interactions. Further, Grunberg–Nissan, McAllister (three-body), and Krishnan–Laddha correlation equations were used for the correlative approach and the obtained results were compared with the experimental viscosities of mixtures. A perusal of comparison shows that the kinematic viscosities calculated with the Krishnan–Laddha relation are in good agreement with the experimental values.

Thermophysical properties of diethylammonium (acetate + water) mixtures at different temperatures

Density (ρ), speed of sound (w), dynamic viscosity (η), and the electrical conductivity (κ) of the protic ionic liquid (PIL) diethylammonium acetate ([DEA][Ac]), in binary mixtures with water, were measured in order to evaluate how these thermophysical properties are affected by the variation of temperature along a wide composition range. The studied temperature range used for ρ and w was (293.15–323.15) K, for η was (283.15–343.15) K, and for κ was (298.15–363.15) K. The pressure was 100.90 kPa. The values obtained for ρ and w were used to calculate the apparent molar volume (vϕ), excess volume (vE), the thermal expansion coefficient (α), and the isentropic compressibility (ks). It was found that temperature affects the properties of the binary mixtures differently and at different degrees, depending on the mole fraction of the PIL. It can also be noted that the electrical conductivity of the system does not depend on its dynamic viscosity only, which would be expected if the electrical conductivity was dominated by diffusion. The other known electrical conductivity mechanisms for PILs are dependent on the formation of hydrogen bonds. Therefore, based on the combined evaluation of the measured properties, [DEA][Ac] seems capable of forming hydrogen bonds with water, leading to high conductivities and making it promising for electrochemical applications.

Recent studies on thermophysical properties of metallic alloys with PROSPECT: Excess properties to construct a solution model

We have developed the system PROSPECT for measuring thermophysical properties at high temperature. Precise thermophysical measurements provide accurate excess functions, which represent non-ideality of solutions. We use excess functions to discuss solution models on the basis of electronic structure and thermodynamics. Pd-Fe systems show positive excess volume VE with negative excess Gibbs energy GE. The phase diagrams of these systems have common features with those of other Pd-X and Pt-X systems (where X is Fe, Ni, Co, or Cu), which means they all have order-disorder transitions. The correlation between VE and GE is discussed in terms of the electronic structure of the alloys, and an energy diagram is proposed to understand this correlation. The excess heat capacity CpE of Fe-Ni melts is positive over a whole composition range and a wide temperature range. We estimate the temperature dependences of the excess enthalpy HE and excess entropy SE of Fe-Ni melts from CpE. The Lupis-Elliott rule is satisfied for HE and SE with positive CpE.

On the Regular Behavior of a Binary Mixture of Ionic Liquids.

Binary mixtures of the ionic liquids 1-ethyl-3-methylimidazolium dicyanamide and tributyl(methyl)ammonium dicyanamide, [C2C1im]x[N4441](1-x)[N(CN)2], are studied by means of their excess properties (enthalpy and volume), their viscosity, and their Raman spectra. The mixtures exhibit positive values of excess volume VE and excess enthalpy HE. The plot of the logarithm of viscosity as a function of composition is consistent with the finding HE > 0. The excess thermodynamic properties of the ionic liquid mixtures are compared with well-known results for binary mixtures of (high-temperature) molten salts. The asymmetry of the curve HE versus composition is reproduced by considering the volumetric fraction of the [C2C1im]x[N4441](1-x)[N(CN)2] mixtures according to basic results of the theory of regular solutions. The anion totally symmetric stretching mode νs(C≡N) was used to probe the local environment around the anion in a Raman spectroscopy investigation of the [C2C1im]x[N4441](1-x)[N(CN)2] mixtures as a function of the composition. The Raman band shape (peak frequency and bandwidth) of the νs(C≡N) mode changes as expected from the fluctuation of concentration around the probe oscillator according to models for vibrational spectroscopy of liquid mixtures. This thermodynamic and spectroscopic study leads to the classification of the [C2C1im]x[N4441](1-x)[N(CN)2] mixture as a regular solution. The application of the regular solution equation for HE to other ionic liquid binary mixtures is discussed.

Measurement and Prediction of Excess Properties of Binary Mixtures Methyl Decanoate + an Even-Numbered n-Alkane (C6–C16) at 298.15 K

The molar excess volumes vE of the three binary mixtures methyl decanoate + n-alkane (n-dodecane, n-tetradecane, and n-hexadecane) were measured at temperature T = 298.15 K and atmospheric pressure...

Volumetric investigation of the ternary system ethanol + dimethylformamide + cyclohexane at 298.15 K

Density measurements have been carried out by means of a vibrating tube densimeter for the ternary system ethanol (EtOH)+dimethylformamide (DMF)+cyclohexane (CyH) and for the binary mixture DMF+CyH. Molar excess volumes VE at 298.15K, as well as excess apparent molar volumes ΦV,iE of the components, have been obtained from the measured quantities. A large miscibility gap is exhibited by DMF+CyH and by the ternary mixtures in the region near this binary. The VE's are largely positive for DMF+CyH and EtOH+CyH, while slightly negative for EtOH+DMF. The VE's of the ternary mixtures are always positive except in a narrow strip in the proximity of the binary EtOH+DMF. The positive sign of VE (as well as of GE and HE) for EtOH+CyH and DMF+CyH, and of large portions of the ternary domain, can be qualitatively explained with a net destruction in the mixing process of H-bonding in EtOH and of dipolar interactions in DMF. The behavior of ΦV,iE of single components confirms that the self-association of EtOH or DMF is the largest in the pure liquids and the least in dilute solution, and that the unlike association EtOH–DMF in the ternary mixtures produces a volume contraction which increases with increasing content of each of the polar components.

Improvements in the Experimentation and the Representation of Thermodynamic Properties (iso-p VLE and yE) of Alkyl Propanoate + Alkane Binaries

This paper presents the experimental measurements of isobaric vapor–liquid equilibria (iso-p VLE) and excess volumes (vE) at several temperatures in the interval (288.15 to 328.15) K for six binary systems composed of two alkyl (methyl, ethyl) propanoates and three odd carbon alkanes (C5 to C9). The mixing processes were expansive, vE > 0, with (δvE/δT)p > 0, and endothermic. The installation used to measure the iso-p VLE was improved by controlling three of the variables involved in the experimentation with a PC. Experimental iso-101.32 VLE data showed a positive consistency with Fredenslund’s point-to-point method. Systems of methyl propanoate + heptane and ethyl propanoate + heptane presented azeotropes (xaz,Taz) at (0.844, 351.86) and (0.481, 366.61), respectively. Representations were obtained of pvE = φ(x,T) and hE = φ(x,T), using a model proposed previously [Ind. Eng. Chem. Res. 2010, 49, 406], and the behavior of the binary systems studied was interpreted. An adequate extended version of the same model was used to perform a stepwise correlation of the different properties according the following order (x,T,cpE)→(x,T,hE)→(x,T,gE), positively valuing the multiproperty correlation. The paper conducts a comparison with the results obtained by applying the nonrandom two-liquid (NRTL) model, which were acceptable with the exception of the inadequate reproduction of values of the second derivative of the Gibbs function. The universal functional activity coefficient (UNIFAC) group contribution model did not give a satisfactory representation of the properties for the binaries of this work.

Densities, Viscosities, and Sound Speed of Binary Mixtures of Hexyl Acetate with Tetrahydrofuran, 1,4-Dioxane, Anisole, and Butyl Vinyl Ether

Densities, viscosities, and speeds of sound for the binary mixtures of hexyl acetate with tetrahydrofuran, 1,4-dioxane, anisole, and butyl vinyl ether were measured at (298.15, 303.15, 308.15, and 313.15) K. From the experimental data, values of excess volume, VE, deviation in viscosity Δη, and deviation in isentropic compressibility ΔKS, have been calculated. These results were fitted to Redlich–Kister polynomial equation. The excess volumes VE and deviations in isentropic compressibility ΔKs were found to be completely negative, while the deviations in viscosity Δη were found to be either negative or positive depending on the nature of liquid mixtures.

Studies on Excess Volume, Viscosity, and Speed of Sound of Binary Mixtures of Methyl Benzoate in Ethers at T=(303.15,308.15, and 313.15) K

Densities, viscosities, and speed of sound have been determined at T = (303.15, 308.15, and 313.15) K for the binary mixtures of methyl benzoate with tetrahydrofuran, 1,4-dioxane, anisole, and butyl vinyl ether over the entire range of composition. Using these measured values, excess volume VE, deviation in viscosities Δη, excess Gibb’s free energy of activation for viscous flow ΔG*E, and deviation in isentropic compressibility Δks have been calculated. These calculated binary data have been fitted to Redlich-Kister equation to determine the appropriate coefficients. The values of excess volume VE and deviation in viscosities Δη are negative over the entire range of composition for all the binary systems at the studied temperatures. The behavior of these parameters with composition of the mixture has been discussed in terms of molecular interactions between the components of liquids.

Excess Gibbs energies and volumes of the ternary system ethanol + dimethylformamide + tetrahydrofuran at 298.15 K

Density measurements have been carried out by means of a vibrating tube densimeter for the ternary system ethanol (EtOH)+dimethylformamide (DMF)+tetrahydrofuran (THF) and for the binary mixtures containing DMF. For the same ternary system and for the binary DMF+THF vapour–liquid equilibrium data have been collected by head-space gas-chromatographic analysis of the vapour phase directly withdrawn from an equilibration apparatus. All experiments have been conducted at 298.15K. Molar excess Gibbs energies GE and volumes VE, as well as activity coefficients γi and excess apparent molar volumes ΦV,iE of the components, have been obtained from the measured quantities. Both binaries involving THF show positive deviations from ideality for GE, while slightly negative deviations are exhibited by EtOH+DMF. The GE's and lnγi of the ternary system are positive almost throughout due to destruction upon mixing of H-bonding in EtOH and dipolar interactions in DMF and THF pure liquids. Feeble negative VE's are displayed by the binaries involving DMF, whereas EtOH+THF shows an S-shaped curve with very small VE values. As a consequence, the VE's and ΦV,iE of the ternary system, differently from GE and lnγi, are negative nearly over the whole composition domain suggesting a more ordered structure in solution, namely that EtOH–DMF association prevails on EtOH and DMF self-association.

Density, ultrasonic velocity, viscosity and their excess parameters of the binary mixtures of N,N-dimethylaniline+1-alkanols (C3-C5), +2-alkanols (C3-C4), +2-methyl-1-propanol, +2-methyl-2-propanol at 303.15K

The density, ultrasonic velocity of sound and viscosity of binary mixtures of N,N-dimethyl aniline (N,NDMA) with 1-propanol, +2-propanol, +1-butanol, +2-butanol, +1-pentanol, +2-methyl-1-propanol, +2-methyl-2-propanol were measured at 303.15 K. These experimental data have been used to calculate excess volume V E , excess ultrasonic speeds u E , excess intermolecular free length L , excess acoustic impedance Z E , excess isentropic compressibility κ , deviation in viscosity Δη and excess Gibbs free energy of activation of viscous flow (G* E ). The values of L and κ are negative over the wide range of composition for all the binary mixtures, while the values of Z E are positive. These results have been used to discuss the nature of interaction between unlike molecules in terms of hydrogen bonding, dipole-dipole interaction, proton-acceptor interaction and dispersive forces. The viscosity data have been correlated using three equations: Grunberg and Nissan, Katti & Chaudhri and Hind et al. The excess/deviations were fitted by a Redlich-Kister equation and the results were analyzed in terms of specific interactions present in these mixtures.

Excess properties of diethyl carbonate + ketone binary mixtures at variable temperatures: Application of PFP theory to excess volumes

Measurements of densities ρ, viscosities η, and refractive indices nD have been carried out for binary mixtures of diethyl carbonate (DEC) with acetophenone, cyclopentanone, cyclohexanone, and 3-pentanone over the entire composition range at the temperatures (303.15, 308.15 and 313.15) K and at atmospheric pressure. From these experimental data, the excess volumes VE, deviation in viscosity Δη and deviation in molar refraction ΔR have been calculated. The Redlich–Kister polynomial equation has been used to estimate the binary fitting parameters and the standard errors. The Prigogine–Flory–Patterson (PFP) theory and its applicability in predicting VE at (303.15, 308.15 and 313.15) K has been tested. The experimental viscosities were analyzed on the basis of Lobe and Auslaender models. Further different mixing rules have been applied to predict the refractive index values of the studied mixtures.

Volumetric properties of the ionic liquids: [C6mim][MeSO4], [C6mim][EtSO4], [C4mim][EtSO4] and their mixtures with methanol or ethanol

Densities of pure ionic liquids, 1-hexyl-3-methylimidazolium methylsulfate [C6mim][MeSO4], 1-hexyl-3-methylimidazolium ethylsulfate, [C6mim][EtSO4], 1-butyl-3-methylimidazolium ethylsulfate [C4mim][EtSO4] and their mixtures with either methanol or ethanol, were measured at temperatures T/K=(283.15, 298.15, 313.15, 328.15) at ambient pressure. The excess volumes VE were correlated by the van Laar equation with the temperature-dependent parameters. Isobaric expansivity and excess isobaric expansivity were described as functions of temperature and composition. The negative deviations from ideal mixing were observed for excess volume VE and the excess isobaric expansivity αE.

Thermodynamics of amine + ketone mixtures 3. Volumetric, speed of sound data and viscosity at (303.15 and 308.15 K) for the binary mixtures of N,N-dimethylaniline + propiophenone, + p-methylacetophenone, + p-chloroacetophenone

Densities ρ, viscosities η and ultrasonic sound speed u of pure propiophenone (PP), p-methylacetophenone (p-MeAP), p-chloroacetophenone (p-ClAP) and those of their binary mixtures prepared using N,N-dimethylaniline (N,N-DMA) as a common component, were measured at 303.15K and 308.15K over the entire composition range. These experimental data have been used to calculate excess volume VE, excess ultrasonic velocity uE, isentropic compressibility κs, intermolecular free length Lf, acoustic impedance Z, excess isentropic compressibility κsE, deviation in viscosity ∆η and excess Gibbs free energy of activation of viscous flow (G⁎E) were evaluated. The viscosity data have been correlated using three equations; Grunberg and Nissan, Katti and Chaudhri and Hind et al. The excess/deviations have been fitted by a Redlich–Kister equation and the results are discussed in terms of molecular interactions present in these mixtures.

Acoustic, thermodynamic and transport properties of binary liquid mixtures of isopentyl acetate with aryl halides at 303.15 and 313.15 K

Densities, viscosities and speeds of sound of the binary systems of isopentyl acetate with chlorobenzene, bromobenzene and fluorobenzene have been measured as a function of composition at 303.15 and 313.15K. Other mixing properties of interest such as excess volumes VE, viscosity deviations ∆η, excess free energy of activation for viscous flow ∆G⁎E, deviation in speeds of sound ∆u, isentropic compressibility KS, deviation in isentropic compressibility ∆KS, intermolecular free length Lf, excess intermolecular free length LfE, specific acoustic impedance Z, and excess specific acoustic impedance ZE have been obtained for each of the system. The calculated excess properties were correlated with the Redlich–Kister Polynomial equation. Further the predictive ability of Grunberg–Nissan, Lobe, Krishnan and Laddha, McAllister (four-body) interaction viscosity models was tested. The speeds of sound data were also correlated using Vandeal–Vangeel and Jouyban–Acree models.

Volumetric, viscometric and optical study of molecular interactions in binary mixtures of diethyl malonate with ketones at 303.15, 308.15 and 313.15K

Density ?, viscosity ?, and refractive index nD were measured for the binary mixtures of diethyl malonate with ketones (acetophenone, cyclopentanone, cyclohexanone and 3-pentanone) at temperatures (303.15, 308.15 and 313.15) K over the entire composition range. Excess volume VE, deviation in viscosity ??, excess Gibb?s free energy of activation for viscous flow ?GE and deviation in molar refraction ?R were determined from the experimental data and computed results were fitted to the Redlich-Kister polynomial equation. The values of VE, ??, ?GE, and ?R were plotted against the mole fraction of diethyl malonate. The observed positive and negative values of excess parameters for all the studied binary mixtures were explained on the basis of intermolecular interactions present in these mixtures. Further different empirical relations were used to correlate the binary mixture viscosities and refractive indices.

Advances in the Correlation of Thermodynamic Properties of Binary Systems Applied to Methanol Mixtures with Butyl Esters

This work analyzes the utility of a new model to correlate thermodynamic properties of solutions, the foundations of which have been published in a previous study. The model is applied to a set of experimental data for several properties of binary systems of methanol with four butyl alkanoates (vapor−liquid equilibria at p = 141.32 kPa and excess enthalpies and volumes at 298.15 and 318.15 K). Vapor−liquid equilibrium data (VLE) indicate that the four binary systems deviate positively from Raoult’s law and do not present azeotrope. Excess enthalpies (hE) are positive for the entire range of compositions and decrease regularly with increasing length of the ester chain, with (∂hE/∂T)p,x > 0. The excess volumes (vE) decrease regularly with the length of the acid chain; they are positive for the binary systems of methanol with butyl (methanoate, ethanoate, and propanoate) and become negative for the system with butyl butanoate, with (∂vE/∂T)p,x > 0. The new model can be used to obtain a satisfactory correlati...

Thermodynamic Excess Properties of the 1-Alkylamine + Alkane and di-n-Alkylamine + Alkane Systems in Terms of an Associated Mixture Model with Equation of State Contribution

AbstractThe model proposed by Treszczanowicz and Benson (1985) is applied for the description and interpretation of excess enthalpyHE, excess volumeVEand excess molar isobaric heat capacityCEpof the binary systems formed by 1-alkylamines and dialkyl-amines withn-alkanes. In the model, the self-association contribution is described by an athermal associated mixture model with the continuous mode of association of the Mecke–Kempter type and the equation of state contribution described by the Flory theory. The three self-association parameters: enthalpy, entropy and volume are valid over the whole homologous series of 1-alkylamines and dialkylamines. The equation of state interaction parameters are correlated for both series of mixtures with the structure of the component molecules by using the Kehiaian–Guggenheim group contribution method. The model predicts reasonably wellHEas well asVEfor both these classes of mixtures.