Separation of pyruvic acid from aqueous solutions by reactive extraction method using trioctylphosphineoxide

Pyruvic acid (CH3-CO-COOH), one of the most important α-oxocarboxylic acids, has been started to be produced by fermentation method in industry in recent years. However, pyruvic acid must be recovered selectively and with high efficiency from the dilute production medium. Many methods have been studied to achieve this goal. With its various advantages, reactive extraction method has come to the fore in recent years and begun to be preferred over other alternatives. In this MS thesis, the recovery of pyruvic acid from aqueous solutions by reaction extraction method using various solvents and Tri-octyl phosphine oxide (TOPO) was investigated. Four different solvents; 1-octanol, 1-decanol, toluene and MIBK were tested as organic phase solvents. The effects of parameters such as solvent type, initial acid concentration, contact time, pH value and extractant concentration on the separation process were investigated. The time for the process to reach equilibrium was determined to be 60 minutes. The highest recovery efficiency was achieved at the natural pH=1.3 of the pyruvic acid solution. A sharp decrease in separation efficiency was observed with increasing pH value. Among the solvents tested, the highest recovery values were obtained with MIBK and toluene, 77.39% (KD=3.38) and 76.85% (KD=3.32), respectively. It was found that the yields obtained with two different solvents at the lowest PA concentrations were very close to each other. While the separation efficiency increased with the amount of extraction agent, it decreased with the pyruvic acid concentration. The observed trends were found to be consistent with many studies in the literature. In this MS thesis study, it has been shown that pyruvic acid can be recovered from water-based solutions by using the TOPO and suitable solvents by reactive leaching. In the following studies, it is aimed to recover pyruvic acid from fermentation media. Keywords: Pyruvic acid, TOPO, Reactive extraction, Separation, Equilibrium