Experimental Mutual Solubility Data for Cyclohexane and Water in Aqueous Solutions of Diethanolamine

Abstract

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.