Experimental Determination of Liquid-Liquid Equilibria under Pressure in an Amine-Water-NaOH Ternary System: Application to the Extraction Process

摘要

In the present paper an experimental apparatus and sampling method were developed for the study of a amine – NaOH – H2O ternary system with vapor pressures from 1 up to 13 bars. The results are important to design new process for the recovery of amine from aqueous mixture by leaching with sodium hydroxide. Three isothermal sections were determined at 298 K, 313 K and 343 K. The compositions of the liquids (miscibility curves, ternary invariant liquids) and the critical points were respectively determined by chemical titration and by the generalized diameter method (Labarthe et al., 2009). Tie line data were also correlated by the Othmer – Tobias method on a massfraction basis (Othmer and Tobias, 1942). Experimental results show the existence of a miscibility gap in the amine – NaOH – H2O system. Further study of these data suggests that it is possible to obtain an organic phase containing more than 95%w of the amine compound.