Lightscattering investigations of the liquidliquid phase transition of the ionic system: Trimethylethylammonium bromide in chloroform
Abstract
Phase diagrams and lightscattering measurements of solutions of trimethylethylammonium bromide in chloroform (ɛ=4.72 at 25 C) with an ethanol content of 1% are reported. The system has a lower critical point near T = 25°C. The critical mole fraction is x_{c},=0.0503 ± 0.0002, which corresponds to the reduced variables T {_{/c } ^{*}}=0.036 and c {_{/c } ^{*}}=0.029 of the restricted primitive model (RPM) and is slightly below the values predicted by the RPM for the critical parameters. The analysis of the scattering intensity at critical composition gives v = 0.631 ± 0.003 for the critical exponent of the correlation length Σ with an amplitude of 0.87± 0.01 nm. The system, a solution of a salt of essentially spherical ions of almost equal size in a simple lowdielectric polar liquid, with critical parameters very close to predictions of the RPM, nevertheless has an Ising critical point.
 Publication:

International Journal of Thermophysics
 Pub Date:
 November 1994
 DOI:
 10.1007/BF01458814
 Bibcode:
 1994IJT....15.1045W
 Keywords:

 chloroform;
 critical phenomena;
 ionic solution;
 light scattering;
 liquidliquid phase transition;
 ternary mixture;
 trimethylethylammonium bromide