Liquid–Liquid Equilibria in Mixtures of 2-Ethylhexanoic Acid, Ethanol, and Water

Mixtures of 2-ethylhexanoic acid (EHA), ethanol, and water are common constituents of precursor solutions for the spray flame synthesis of nanoparticles. As EHA and water are poorly miscible, the question arises whether phase separation can occur during the process. Since no experimental data on liquid–liquid equilibria (LLE) in mixtures of EHA, ethanol, and water are available in the literature, they were measured in the present work. Binary and ternary LLE were studied at temperatures between 283 and 333 K. A thermodynamic nonrandom two-liquid model (NRTL) was adjusted to the data from this work and to vapor–liquid equilibrium data from the literature. With this model, residue curves in the ternary system were calculated, which indicate that liquid–liquid demixing upon the evaporation of droplets in the spray flame synthesis process is unlikely.