Extraction of carboxylic acids with amine extractants. 3. Effect of temperature, water coextraction, and process considerations

Abstract

Coextraction of water during extraction of succinic acid by Alamine 336 in different diluents has been measured. The amounts of coextracted water lie in the same order as the solubilities of water in the diluents without amine present. Water coextraction with different acids follows the order fumaric > malonic > maleic = succinic > lactic > acetic. The effects of temperature on extraction of succinic and lactic acids by Alamine 336 with chloroform and methyl isobutyl ketone (MIBK) diluents have been measured. Enthalpies and entropies of complex formation have been derived from the results and are interpreted in terms of the differences in interactions among the species involved. Two approaches for regeneration through back-extraction into an aqueous phase are considered. These involve changes in the equilibrium relationship through a swing of temperature and a swing of diluent composition, respectively. The factors underlying the utility of each are explored and contrasted. The two approaches may be used in combination.In the production of carboxylic acids, processes such as fermentations produce multicomponent, aqueous solutions with product acid concentrations typically 10% w/w at most, and usually substantially less. Subsequent separation, purification, and concentration of these acids is difficult because of the high affinities of the acids for water.Distillation of dilute, nonvolatile acids involves large energy consumption for the heat of vaporization of water, which must be taken overhead. Furthermore, distillation cannot fractionate among nonvolatile acids. The low aqueous Biotechnol. 1983, 33B, 85-94.

Propionic acid production by extractive fermentation. I. Solvent considerations

“…Procedures for acid recovery from the solvent have included back extraction with water at higher temperature (temperature swing) (Tamada and King, 1990b), back extraction with caustic (Eyal and Bressler, 1993;Yang et al, 1991), and distillation (Poole and King, 1991). The choice of methods depends not only on the properties of the acid and the solvent to be separated, but also on the form of product desired.…”

Recovery of Glutaric Acid Using Tri-N-Butyl Phosphate: Effect of Diluents and Temperature

“…In high temperature range, change in enthalpy (∆H) and entropy (S) of the reaction are studied [7]. The equilibrium complexation constant is correlated with temperature, enthalpy and entropy and it can be expressed by the following equation.…”

Approaches for regeneration of amine-carboxylic acid extracts

“…Tables 1 and 2 show values for the apparent OH and OS and values for OH,,,,, and OStrans obtained by Tamada and King [12] from a linear least-squares fit of the experimental data. A sufficiently large enthalpy change is needed for temperature-swing regeneration to be attractive.…”

“…Figure 5 [12] shows that lower proportions of chloroform (the active diluent) in a chloroform-heptane diluent greatly decrease the equilibrium extraction of succinic acid in the forward direction. Therefore a regeneration process can be carried out with a lower active diluent content.…”