Ionic Liquid - Rb < Sub > 2 < / Sub > Co < Sub > 3 < / Sub > / Cs < Sub > 2 < / Sub > Co < Sub > 3 < / Sub > New Phase Behavior Of The Aqueous Two-phase System And Its Application In L - Tryptophan Separation And Enrichment

Ionic liquid-based aqueous two-phase systems (ATPS), a new kind of systems emerged recently, have many advantages such as environment friendly, low viscosity, quick phase separation and little emulsion for extraction process. Thus, the ionic liquid-based ATPS have attracted much attentions since they have potential applications for the separation and purification of biomolecules. In this thesis, Rb2CO3and CS2CO3were firstly selected to form novel ATPS with ionic liquids, and the main research progresses are as following:The binodal curve data for [C2mim]Br/[C3mim]Br/[C4mim]Br/[C3’mim]Br (1)+Rb2CO3/CS2CO3(2)+H2O (3) two-phase systems at different temperatures were determined by the cloud point method. The effect of temperature, ionic liquid structure and inorganic salt were studied, respectively. The results showed that the two-phase area is not expanded with increasing temperature. The phase-forming ability of the four ionic liquids follows the order:[C4mim]Br>[C3mim]Br>[C3’mim]Br>[C2mim]Br. Moreover, for the same temperature and ionic liquid, Rb2CO3is easier to form two phase systems than CS2CO3. The experimental binodal curves were correlated using the empirical relationship described by Merchuk. The tie-lines (TLs) for [C2mim]Br/[C3mim]Br/[C4mim]Br/[C3’mim]Br (1)+Rb2CO3/Cs2CO3(2)+H2O (3) two-phase systems at different temperatures were determined by a empirical correlation method for density and refractive index. The tie-lines data were correlated with the Othmer-Tobias and Bancroft equations.Partition coefficients of L-tryptophan were determined in [C2mim]Br/[C4mim]Br/[C3’mim]Br (1)+Cs2CO3(2)+H2O (3) two-phase systems. The effect of the temperature, salt concentration and the structure of ionic liquids on L-tryptophan partition were investigated. Experimental results show that L-tryptophan partitioning coefficients decreased with a rise of temperature, which show that the transfer of L-tryptophan between the Cs2CO3-rich phase and the IL-rich phase is an exothermic process. However, this effect is not obvious. The extraction separation for L-tryptophan is suitable for the room temperature. With a rise of CS2CO3concentration, L-tryptophan partitioning coefficients increased. Furthermore, the partition ability of the ionic liquids follows the order:[C4mim]Br>[C3’mim]Br>[C2mim]Br. All the partition coefficients are much larger than that for the traditional PEG-aqueous two-phase systems.The phase behavior investigation for ionic liquids-Rb2CO3/CS2CO3ATPS can not only provide much basic data to develop solution chemistry, but also provide an effective method for separation and purification of biomolecules.