Pentafluoroethane Dehydration with Ionic Liquids

Ionic
liquids (ILs) were proposed as promising separating agents
for the hydrofluorocarbons (HFCs) pentafluoroethane (R125) dehydration.
Taking into account the H2O solubility and selectivity
of H2O to R125 in a variety of IL candidates, we determined
the hydrophilic [EMIM]­[BF4] as a satisfactory absorbent.
Besides, some theoretical insights into separation mechanism at the
molecular level were explored by means of the combination of COSMO-RS
model and quantum chemistry calculation. The gas–liquid equilibrium
(GLE) data for the binary R125-[EMIM]­[BF4] and ternary
R125-H2O-[EMIM]­[BF4] systems were measured,
and the experimental data were compared with the predicted results
by COSMO-RS model. The R125 dehydration experiment with IL was carried
out. Furthermore, the continuous processes for R125 dehydration with
[EMIM]­[BF4] and the conventional benchmark solvent tetraethylene
glycol (TeEG) as absorbents were simulated and optimized with the
rigorous equilibrium (EQ) stage model, in which COSMO-SAC model was
selected. It was confirmed that the R125 gas dehydration with IL presented
in this work is a typical process intensification technology.