Measurement and Correlation of Solid−Liquid Equilibria of 18-Crown-6 in Alcohols. 1

Abstract

The solid-liquid equilibria of 13 binary mixtures of 1,4,7,10,13,16-hexaoxaoctadecane (18-crown-6) in alcohols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butyl alcohol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-dodecanol) have been determined experimentally by a dynamic method in temperature range from 275 K to the melting temperature of 18-crown-6. The results of solubility have been correlated by the Wilson, NRTL 1, and UNIQUAC equations. The existence of solid-solid first-order phase transition in 18-crown-6 has been taken into consideration in the solubility calculations. The best correlations of the solubility data have been obtained by the Wilson equation, where the average root-mean-square deviation of the solubility temperature is 0.45 K.

The Water–18-Crown-6 System: Experimental Investigation and Thermodynamic Modeling

“…To control the quality of 18-crown-6, its melting point was measured by differential scanning calorimetry (DSC) on a 204 HP Phoenix in a dry argon flow (10 –5 m 3 ·min –1 ) in the temperature range of (263.15 to 333.15) K at a heating rate of 2 K·min –1 . The melting point of 18-crown-6 agreed well with the literature data [mp = (39.1 and 39.3) °C, respectively] . For the preparation of aqueous solutions distilled water was used.…”

“…The melting point of 18-crown-6 agreed well with the literature data [mp = (39.1 and 39.3) °C, respectively]. 18 For the preparation of aqueous solutions distilled water was used.…”

Stability Constants for the 18-Crown-6–Sodium Ion Complex in Mixtures of Water and Butan-1-ol or Butan-2-ol

“…Crown ether was purified from impurities by standard recrystallization from acetonitrile. The sample was considered to be pure if there were no anomalies in thermoanalytical curves, which were measured by differential scanning calorimetry on a Netzsch DSC 204 F1 calorimeter, and if the melting point and the enthalpy of melting were equal to the published values for 18-crown-6: T m = 312.25 K, Δ m H = 35.5 kJ·mol –1 and T m = 312.45, Δ m H = 36.66 kJ·mol –1 …”

Guidelines for reporting of phase equilibrium measurements (IUPAC Recommendations 2012)

“…Table 5: (Solid + liquid) equilibrium data; often termed "solubility" data [72]. Table 6: (Solid + liquid) equilibrium data; often termed "SLE phase diagram" data [73]. The experimental data are shown in Fig.…”