Lactic acid extraction with trioctyl amine

Abstract

Lactic acid extraction was carried out with trioctyl amine (TOA) in three diluents. The effect of initial lactic acid concentrations on the extraction ef®ciency was investigated. It was observed that although the percentage extraction remained constant or decreased but the loading ratio was increased in all the cases. The overloading was observed in the case of TOA in methyl isobutyl ketone (MIBK). The extraction of lactic acid was favored at a lower aqueous pH in all the diluents. The improvement of the extraction ef®ciency at a higher aqueous pH ( 6) was achieved by using the modi®ed TOA (treated with HCl) in MIBK. However, the recovery of lactic was very poor in the case of modi®ed TOA in MIBK, although the complete recovery was obtained for untreated TOA.

Liquid–Liquid Equilibria of Lactic Acid/Water Solutions in Tri-iso-octylamine/Dodecane/1-Dodecanol at 306.1, 310.1, and 316.1 K. Experimental Data and Prediction

“…15 Active diluents (called modifiers 15 as well) are organic compounds that contain polar groups with the capacity of stabilizing the bond of the formed acid−amine complex by solvation 16,17 favoring the extraction process. 17 Active diluents provide a strong effect on the extraction mechanism 5 and change the activity coefficients of the complex. 12 For instance, the acid and the amine form a complex by ion-pair in an organic phase containing an active diluent while it forms a complex by H-bond in an organic phase with an inert diluent.…”

“…Inert diluents are usually nonpolar organic compounds that are used to improve the physical properties of the organic phase . Active diluents (called modifiers as well) are organic compounds that contain polar groups with the capacity of stabilizing the bond of the formed acid–amine complex by solvation , favoring the extraction process . Active diluents provide a strong effect on the extraction mechanism and change the activity coefficients of the complex .…”

Comparison of Lactic Acid Productivities at High Substrate Conversions in a Continuous Two-stage Fermenter With Cell Recycle Using Different Kinetic Models

“…In order to achieve low costs and high production rates of lactic acid fermentation processes, various microbiological attempts have been carried out (Litchfield, 1996). One typical method with a high rate of fermentation is to use a membrane recycle bioreactor system (Litchfield, 1996;Xavier et al, 1995;Melzoch et al, 1997;Choudhury and Swaminathan, 1998;Kwon et al, 2001). In this system, a continuous stirred tank fermenter is coupled in a semi-closed loop with a membrane filter for cell separation, and the concentrated cells are returned to the fermenter for recycling.…”

Investigation of liquid–liquid phase equilibria for reactive extraction of lactic acid with organophosphorus solvents

“…High partition coefficients are achieved with secondary and tertiary amines. But re‐extraction is often carried out with bases because of high thermal stability due to the ionic character of amine salts . With increasing concentration of bases the tendency for emulsification increases.…”