Recovery and separation of lactic and malic acids from fermentation broth with N,N,N,N-Tetrabutylbutanediamide by reactive liquid−liquid extraction and stripping

Abstract

It is of great importance to extract and separate lactic and malic acids which used as raw materials in chemical industry. Taking into account its desirable selectivity of lactic and malic acids, the discovery of the novel extractant called N,N,N,N-Tetrabutylbutanediamide (N4423) is a innovation in this paper. Separation and purification the malic and lactic acids that present in the fermentation broth by reactive liquid-liquid extraction is the principal objective of this study. The lactic acid extraction was ideal when the reaction performed in the optimum conditions: 60 wt% of N4423, phase ratio (O/A) of 3, temperature at 35°C and magnetic stirred 5 minutes. As a result, the purity of lactic acid exceeded 98%. Based on the slope method, the equilibrium concentration of lactic and malic acids in the organic phase were high enough to form the complexes which the mole ratio of N4423 to lactic acid and malic acid were 1.61, 1.86 respectively. FT-IR characterization indicated that the formation of hydrogen bonding between N4423 and lactic acid were predominant to the excellent extraction efficiency. The adopted reactive liquid-liquid extraction method is of low cost, low energy consumption and environmental friendliness. The N4423 has good extraction and separation efficiency of lactic and malic acids, the obtained lactic acid has high purity. The results gathered in this work might prove to be a potential approach to acquire lactic and malic acids.