Patent ID: 6087532
Filing Date: 2000-07-11
Classification: C12P

Abstract:
A process for isolating lactic acid; said process including the steps of:(a) forming a first phase including 40-70%, by wt., sodium lactate, in solution;(b) forming a second, water-immiscible, phase including:(i) 30-95%, by wt., trialkyl amine selected from the group consisting of: trihexylamine, trioctylamine, triisooctylamine, tricaprylylamine, tridodecyl amine and mixtures thereof;(ii) 5-70%, by wt., solvent including:(A) liquid hydrocarbon; and(B) alkanol selected from the group consisting of isopropanol, n-butanol, n-octanol and mixtures thereof; and,(iii) dissolved CO.sub.2 under a partial pressure of at least 75 psig;(c) contacting the first aqueous phase with the second, water-immiscible, phase in an extraction process under a partial pressure of CO.sub.2 of at least 75 psig;(i) said step of contacting including a feed ratio of water-immiscible phase to aqueous phase, into the extraction process, within the range of 15:1 to 1:1; and,(ii) said step of contacting comprising a countercurrent extraction process;(d) recovering from the countercurrent extraction process:(i) a separated aqueous phase or slurry including sodium bicarbonate; and,(ii) a separated water-immiscible phase including lactic acid values;(e) decompressing the separated water-immiscible phase from step (d) to release a majority of dissolved CO.sub.2 therefrom, and to form a CO.sub.2 decompressed, water-immiscible, lactic acid containing phase; and(f) conducting an aqueous extraction of the CO.sub.2 decompressed, water-immiscible, lactic acid containing phase to extract lactic acid into an aqueous phase.