Study On Solid-Liquid Equilibria Of Some Organic Systems

The solid-liquid equilibria were an important part of thermodynamicresearch, and also were the foundation of industrial crystallization. Study onsolid-liquid equilibria played a crucial role in chemical industry. In this paper,hexamethylenetetramine,1-adamantanamine hydrochloride and ribavirin wereselected as solute to do organic solid-liquid equilibria research.The solid-liquid equilibria for binary system of hexamethylenetetramine-methanol, hexamethylenetetramine-ethanol, hexamethylenetetramine-1-propanol,hexamethylenetetramine-2-propanol, hexamethylenetetramine-1-butanol andhexamethylenetetramine-1-pentanol were measured using a laser monitoringobservation technique with the dynamic method. The result indicated that thesolubility of hexamethylenetetramine in all solvent increased with an increasein temperature, and was the maximum in methanol. Apelblat equation, λhequation and Wilson equation were used to correlate the experimental data,the average relative deviations of three methods were0.89%,1.23%and1.97%, respectively.The solid-liquid equilibria for ternary system of hexamethylenetetramine -methanol-ethanol,1-adamantanamine hydrochloride-ethanol-DMF and ribavirin-acetic acid-NMP were determined in this paper, respectively. And Wilsonequation, λh equation and polynomial equation were used to correlate theexperimental data. The results showed that polynomial equation was the best.The c-CH₂group in ring structure was used in this work to improve theprediction accuracy of UNIFAC equation for this experimental system, and theinteraction parameters were regressed using the experimental data of binarysystem of hexamethylenetetramine. Finally, the average relative deviations ofUNIFAC method for binary and ternary system of hexamethylenetetramineusing new group parameters were1.62%and2.16%, respectively.