Effects of temperature and pH on phase behavior for the ternary systems of water + inorganic salt + alkoxyethanols at atmospheric pressure

Abstract

The effects of temperature, pH, inorganic salts, as well as molecular structure on the phase behavior of water + salt + alkoxyethanol(CnEm, n = 2-4, m = 1-3) ternary systems were investigated. Binodal data for water + NaCl + C2E1, C3E1, C4E1, C4E2, C4E3 were obtained and correlated to investigate how the system's phase-split ability is influenced by the type of alkoxyethanol. In addition, the binodal data for aqueous solution of C4E1 with NaCl, KCl, CsCl, NaF, NaBr were investigated to understand the effects of the salts. Furthermore, the complete two-liquid-phase coexistence regions for water + NaCl + C4E1 at T = (283.15, 293.15, 303.15, 313.15) K were acquired to investigate the effects of temperature. The liquid-liquid equilibria (LLE) were also studied based on tie-line data, in which three correlation equations, the Othmer-Tobias equation, the Bancroft equation and the Setschenow equation were used. Finally, the binodal data of water + NaCl + C4E1 was measured at pH = (3, 5, 7, 9, 11) to investigate the impact of pH.