Orientador(es)
Resumo(s)
Solid-liquid equilibria (SLE) data for two binary organic mixtures of N-(2-methoxyethyl)-p-nitroaniline+Nethyl-
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.
Descrição
Palavras-chave
Eutectic mixture Excess thermodynamic properties Microstructure Physicochemical characterization Propellant stabilizer Semi-empirical models
Contexto Educativo
Citação
Chelouche, Salim; Trache, Djalal; Neves, Catarina M.S.S.; Pinho, Simão P.; Khimeche, Kamel; Benziane, Mokhtar (2018). Solid + liquid equilibria and molecular structure studies of binary mixtures for nitrate ester's stabilizers: Measurement and modeling. Thermochimica Acta. ISSN 0040-6031. 666, p. 197-207