Experimental solid–liquid–liquid equilibrium data for the H2O + NaOH + pyrrolidine ternary system. Application to the extraction of N-aminopyrrolidine

Salting-out using sodium hydroxide is a simple and relevant method of pre-concentrating organic compounds (amine + hydrazine) in crude synthetic solutions during the preparation of hydrazine products. Liquid–liquid, solid–liquid and solid–liquid–liquid equilibria were determined for the pyrrolidine + water + sodium hydroxide ternary system at 283.15 K, 293.15 K and 323.15 K under atmospheric pressure. The reliability of our experimental tie-lines data was confirmed by using the Othmer–Tobias correlation. Distribution coefficients and separation parameters were evaluated for the immiscibility region. Using the data in these isothermal sections, we can deduce the demixing temperature that transfers most organic compounds to the upper phase and also the composition of the organic phase recovered after this first extraction step.