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The experimental measurement of density and enthalpy of mixture for two binary liquid mixtures of n-tridecane or n-tetradecane with decalin was reported in this paper. The measurements were conducted at a temperature range of 293.15–323.15 K and at 303.15 K using calorimeter C80. The mixtures were analyzed at various proportions, including the entire composition range and dilute solutions. The excess molar volume (VE) and excess molar enthalpy (HE) of mixtures were calculated and fitted using the Redlich–Kister equation. The paper observed the expansion phenomenon for the VE at all temperatures, including over the entire composition range and dilute solutions. Additionally, the HE exhibited endothermic behavior at the studied temperature range and composition range. The Prigogine–Flory–Patterson (PFP) theory was utilized to predict both thermodynamic properties, namely the VE and HE. The results obtained using the PFP theory were compared with those obtained using the Treszczanowicz and Benson association (TB) model for VE and with the NRTL, Wilson, and Flory models for HE. The PFP model, which employed a single-fitted parameter to describe VE, demonstrated satisfactory performance in predicting VE. Conversely, the Treszczanowicz and Benson association (TB) model yielded relatively poor results in fitting VE. However, the NRTL, Wilson, PFP, and Flory models exhibited good performance in predicting HE. [ABSTRACT FROM AUTHOR]

The present work falls within the research line focused on the phase equilibria of binary mixtures comprising typical compounds, widely present in biodiesel/petrodiesel blends. The study was performed by investigating the liquid–vapor equilibria and thermodynamic properties of two binary systems: ethyl octanoate (1) + n-tetradecane (2) and ethyl dodecanoate (1) + n-tetradecane (2) using experimental and computational methods. The experimental data of vapor pressures were measured through a static apparatus at nine temperatures from (373.15 K and 453.15 K) with an interval of 10 K. The obtained experimental data are used to determine the activity coefficients (γi) and excess molar Gibbs energies (GE) of the investigated binary mixtures by applying the Redlich–Kister equation according to Barker's method. Positive values of the excess molar Gibbs energy are obtained for all the investigated constant temperatures and over the whole composition range. The obtained GE values were correlated by using two semi-predictive models (NRTL and Heil). The prediction displays agreement with the experimental data obtained with Barker's method. The present work provides a set of thermodynamic data that may be very useful for the development of eco-friendly alternative biodiesel. [ABSTRACT FROM AUTHOR]

The vapor pressures of three binary systems ethyl hexanoate (1) + n-dodecane (2), ethyl decanoate (1) + n-dodecane (2) and ethyl tetradecanoate (1) + n-dodecane (2) were measured by means of a static apparatus at temperatures between 373.15 and 453.15 K. The data were correlated with the Antoine equation. From these data, the molar excess Gibbs energies G were obtained with Barker's method and fitted to the Redlich-Kister equation. The excess Gibbs energy is positive for all the investigated constant temperatures and over the whole composition range. The Wilson equation was used and good results were obtained in the prediction of the total pressure and thermodynamic excess properties; however, deviations were observed with respect to the experimental and predicted G , using UNIFAC (Dortmund) group contribution model. [ABSTRACT FROM AUTHOR]

Differential scanning calorimetry (DSC) is used to investigate the thermal properties of N-(2-ethanol)-p-nitroaniline + N-(2-acetoxyethyl)-p-nitroaniline, and their binary systems. The experimental results demonstrate that the studied binary system presents a simple eutectic behavior and the corresponding mole fraction (xeu) of N-(2-ethanol)-p-nitroaniline at the eutectic point is 0.5486, whereas the temperature (Teu) is found to be equal to 363.6 K. The quality of the solid-liquid equilibria (SLE) data has been checked by thermodynamic consistency tests, presenting good quality factor. The SLE data have been correlated by means of Wilson, NRTL, and UNIQUAC equations. The three models describe satisfactorily the phase diagram as the root-mean-square deviations for the equilibrium temperatures vary from 1.25 K to 2.07 K. Nevertheless, the Wilson model provides the best correlation results. The three equations have also been used to compute excess thermodynamic functions viz. excess Gibbs energy, enthalpy and entropy. The obtained results revealed a sensitive positive deviation to ideality thus demonstrating the nature of the interactions between the compounds forming the mixture. Microstructural studies have been carried out by FTIR, XRD and optical microscopy showing weak molecular interactions for the eutectic mixture. [ABSTRACT FROM AUTHOR]

Solid-liquid equilibria (SLE) data for two binary organic mixtures of N-(2-methoxyethyl)-p-nitroaniline + N-ethyl-4-nitroaniline (S1) and N-(2-ethanol)-p-nitroaniline + N-ethyl-4-nitroaniline (S2) have been measured using differential scanning calorimeter to build the corresponding solid-liquid phase diagrams. The quality of the SLE data has been checked by consistency tests, presenting good quality factors for both systems. Simple eutectic behavior has been observed for these systems with the presence of a solid-solid transition for S2. The SLE data have been correlated by means of Wilson, NRTL, and UNIQUAC equations. The used models calculate the equilibrium temperatures very satisfactorily. The best modeling results were obtained using the Wilson equation with a root mean square deviation between experimental and calculated values for S1 and S2 of 1.15 and 1.99, respectively. The Wilson, NRTL, and UNIQUAC equations have also been used to compute excess thermodynamic functions viz. excess Gibbs energy, enthalpy, and entropy. The obtained results demonstrated a moderate positive deviation to ideality for S1, and a strong positive deviation for S2, unveiling the nature of the interactions between the compounds forming each mixture. In addition, microstructural studies have been carried out by FTIR, XRD and optical microscopy. Weak molecular interactions have been shown for the eutectic compositions. Jackson’s roughness parameter was calculated and found to be greater than 2, suggesting the faceted morphology with irregular structures. [ABSTRACT FROM AUTHOR]