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 developedrnfor the study of a amine – NaOH – H2O ternary system with vapor pressures from 1 uprnto 13 bars. The results are important to design new process for the recovery of aminernfrom aqueous mixture by leaching with sodium hydroxide. Three isothermal sectionsrnwere determined at 298 K, 313 K and 343 K. The compositions of the liquidsrn(miscibility curves, ternary invariant liquids) and the critical points were respectivelyrndetermined by chemical titration and by the generalized diameter method (Labarthe etrnal., 2009). Tie line data were also correlated by the Othmer – Tobias method on a massfractionrnbasis (Othmer and Tobias, 1942). Experimental results show the existence of arnmiscibility gap in the amine – NaOH – H2O system. Further study of these data suggestsrnthat it is possible to obtain an organic phase containing more than 95%w of the aminerncompound.