Measurement and correlation of the (vapor + liquid) equilibria of pure 4-ethylmorpholine, 1,2-dimethylisopropylamine and N,N-dimethylethanolamine, and their binary aqueous solutions

• Vapor pressures of 4-ethylmorpholine, DMIPA and DMAE and their aqueous solutions.
• The investigated temperatures are from 273 K through 363 K.
• The two first mixtures show positive azeotropic behavior and exhibit positive GE.
• The third solution shows either positive or sinusoidal shape for GE.
• The Wilson, NRTL and UNIQUAC models were applied.

The vapor pressures of (4-ethylmorpholine + water), (1,2-dimethylisopropylamine + water), (N,N-dimetylethanolamine + water) binary mixtures, and of pure 4-ethylmorpholine, 1,2-dimethylisopropylamine and N,N-dimethylethanolamine components were measured by means of two static devices at temperatures between {273 (or 283) and 333 (or 363)} K. The data were correlated with the Antoine equation. From these data excess Gibbs functions (GE) were calculated for several constant temperatures and fitted to a fourth-order Redlich–Kister equation using the Barker’s method. The (4-ethylmorpholine + water), and (1,2-dimethylisopropylamine + water) binary systems show positive azeotropic behavior. The aqueous solutions of 4-ethylmorpholine and 1,2-dimethylisopropylamine exhibit positive deviations in GE for all investigated temperatures over the whole composition, where the aqueous solution of N,N-dimetyhlethanolamine show a S shape for GE for (273.15 < T < 313.15) K. Additionally, the Wilson, NRTL or UNIQUAC models have been used and quite good results were obtained in the prediction of the total pressure.