This study presents liquid–liquid
equilibrium solubility data of the mutual solubility of cyclohexane
and water in aqueous solutions of diethanolamine (DEA). Measurements
were taken using a series of jacketed cells connected to a thermostat
to maintain the desired solubility temperature. Different concentrations
of DEA (15, 25, 35, 45, and 50 wt %) were prepared and mixed with
cyclohexane in the measuring cells at temperatures ranging from 298
to 318 K and atmospheric pressure. Once thermodynamic equilibrium
had reached, samples from the aqueous phase were analyzed for cyclohexane
content using a gas chromatograph-mass spectrometer, while samples
from the hydrocarbon-rich phase were analyzed using a water content
apparatus. Results showed that the solubility of cyclohexane increased
with an increase in DEA concentration and varied directly with the
temperature. Similarly, the solubility of water in the organic phase
exhibited an increasing trend with an increase in temperature and
concentration of DEA. The alkanolamine concentration effect was modeled
using an activity coefficient model that was successfully used to
estimate the activity coefficient of cyclohexane in the aqueous DEA
phase from the measured solubility data.