A method for a liquid-liquid extraction of hydrophilic organic compounds
from aqueous solutions thereof is described. The method generally
includes intermixing a sufficient quantity of a specified glycol ether
with the aqueous liquor at a first temperature to form a suspension
comprising an aqueous raffinate phase and a glycol ether extract phase;
separating the glycol ether extract phase from the aqueous raffinate
phase; heating the glycol ether extract phase to a second, higher
temperature to form a suspension comprising an aqueous extract phase
containing a portion of the hydrophilic organic compound and a glycol
ether raffinate phase; and separating this glycol ether raffinate phase
from the aqueous extract phase. The selected glycol ether has an inverse
solubility in water and the partition ratio, value K, for the hydrophilic
organic compound is greater than 0.1. This method is useful for
recovering valuable hydrophilic organic acids produced via fermentation
or produced or used in various manufacturing processes.