Equilibrium and Kinetic Studies on Reactive Extraction of Pyruvic Acid with Trioctylamine in 1-Octanol

Abstract

Interest in pyruvic acid has been growing due to the increase in its potential areas of use and its importance in metabolic reactions. These reasons along with the limitations on recovery have prompted researchers to consider novel recovery techniques. Reactive extraction has been proposed as a promising approach to the recovery of carboxylic acids. In this study, equilibrium and kinetic data were obtained for reactive extraction of pyruvic acid using trioctylamine (TOA) or Alamine 336 in 1-octanol or oleyl alcohol. The results showed that, without pH adjustment in the aqueous phase, and without the use of an extractant, 1-octanol extracted more pyruvic acid than oleyl alcohol with a distribution coefficient (K D ) of 0.30. This trend remained the same when tertiary amines were used as an extractant. The K D values did not significantly differ with TOA or Alamine 336. The recovery of pyruvic acid was observed to increase as a function of TOA concentration and the stoichiometry of the reaction was mainly 1:1. As tertiary amines react only with undissociated acids, an increase in the initial pH of the aqueous phase lowered the K D values. When the pH was 4.0, the effect of TOA concentration on pyruvic acid extraction disappeared and for all concentration levels a distribution coefficient of 0.10 was obtained. Kinetic measurements showed that the reaction between pyruvic acid and TOA in 1-octanol is first order with respect to the two reactants with a rate constant of 0.94 L mol À1 s À1 . The enhancement factor was calculated as 25.

Recovery of Formic Acid by Reactive Extraction Using an Environmentally-Friendly Solvent

“…This was valid for almost all FA concentrations. The results obtained for the investigation of the acid concentration effect were consistent with the literature (Tamada et al, 1990;Gu et al, 1998;Keshav et al, 2009;Martı et al, 2011;Uslu et al, 2014;Martı et al, 2016).…”

“…However, at the same extractant levels and higher FA concentrations, the z values varied between 1 and 2, indicative of the simultaneous presence of 2:1 and 1:1 type acid-amine complexes. The results are consistent with those reported in the literature for tertiary amines and carboxylic acids (Tamada et al, 1990;Wasewar et al, 2002;Qin et al, 2003;Uslu, 2009;Martı et al, 2011) CONCLUSION Solvent or diluent type used during reactive extraction is so important for the recovery of carboxylic acids (Kertes and King, 1986). However, the most effective solvents are generally toxic chemicals and this is the most critical disadvantage of the technique that prevents its widespread use in industries.…”

“…It was shown that the recovery with reactive extraction was significantly influenced by the concentration and type of the acid (Gu et al, 1998;Martı et al, 2011;Martı and Gürkan, 2015). Figure 3 shows that the recovery efficiencies were influenced in different ways by initial FA concentrations when octanol or SFO was selected as the organic phase diluent.…”

“…Several separation techniques such as solvent extraction, distillation, membrane filtration, electrodialysis, ion exchange and adsorption have been tested for the purpose (Martı 2010). Reactive extraction, which is the advanced form of traditional solvent extraction method, has been favored over other techniques due to its high efficiency, ease of operation, low energy demand and cost (Kertes and King, 1986;Martı et al, 2011). Another advantage of the technique is thermal stability of the target molecule during the process (Martı and Gürkan, 2015).…”

Liquid-liquid extraction equilibrium for pyruvic acid recovery: experimental data and modeling

“…However, a few technical problems exist at the purification and separation stage that could be resolved by using liquid -liquid extraction (Marti et al, 2011). Extraction is a highly energy efficient, cheap and sustainable technique that could provide high yield and selectivity over conventional methods of separation of carboxylic acids from fermentation broth.…”