Liquid-Liquid Equilibrium of Water+ 1-Butanol+ Amino Acid (Glycine or DL-Alanine or L-Leucine)

Abstract

Amino acids play an important role both in animal metabolism and in industrial processes.Since they are rarely found in nature in a free form, they must be obtained from hydrolysis ofprotein-containing materials, or by fermentation. These production methods often result inaqueous mixtures containing various solutes including several types of amino acids. As aconsequence, the cost of the separation processes and concentration of biomolecules from themedia can be as high as 90 per cent of their total manufacturing cost. In this way, the designof such processes requires the knowledge of the partitioning behaviour in two-phase systemsand thermodynamic models should support this optimization procedure. However, both thecomplexity of biomolecules, due to their multiple functional groups, and the crucial role ofwater, make the standard available thermodynamic models unattractive for the computation ofphase behaviour. Therefore, new thermodynamic models for the description of the phasebehaviour of systems containing biomolecules are required.In this work, liquid-liquid equilibria (LLE) of the ternary systems 1-butanol/water/amino acid(glycine, DL-alanine or L-leucine) were measured at 40 oC. The experimental results werecorrelated and interaction parameters for the modified-NRTL, UNIFAC and UNIFACCampinas models were estimated.