Formation and characteristics of aqueous two-phase systems formed by a cationic surfactant and a series of ionic liquids.
Aqueous two-phase systems (ATPS) were obtained in the aqueous mixtures of a cationic surfactant and a series of ionic liquids (ILs). The effects of IL structure, temperature and additives on the phase separation were systematically investigated. The microstructures of some ATPS were observed by freeze-fracture replication technique. Lyotropic liquid crystal was found in the bottom phase besides micelles under different conditions. Remarkably, both IL structure and additives profoundly affected the formation and properties of the ATPSs. The phase separation can be attributed to the existence of different aggregates and the cation-π interactions of the cationic surfactant with the ILs, which has a significant role in the formation of ATPS. The extraction capacity of the studied ATPS was also evaluated through their application in the extraction of two biosubstances. The results indicate that the ILs with BF4(-) as anion show much better extraction efficiencies than the corresponding ILs with Br(-) as anion do under the same conditions. l-Tryptophan was mainly distributed into the NPTAB-rich phase, while methylene blue and capsochrome were mainly in the IL-rich phase.
Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong 252059, PR China. Electronic address: weixilian@lcu.edu.cn.
Xi-Lian
XL
Wei
Xiu-Hong
XH
Wang
A-Li
AL
Ping
Pan-Pan
PP
Du
De-Zhi
DZ
Sun
Qing-Fu
QF
Zhang
Jie
J
Liu
D000596:Amino Acids / Q000737:chemistry / Q000302:isolation & purification; D002412:Cations; D005591:Chemical Fractionation / Q000379:methods*; D007093:Imidazoles / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry / Q000302:isolation & purification; D008956:Models, Chemical; D012212:Rheology; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D014783:Viscosity
D000596:Amino Acids; D002412:Cations; D007093:Imidazoles; D052578:Ionic Liquids; D013501:Surface-Active Agents; D008751:Methylene Blue
Additives; Aqueous two-phase systems; Cationic surfactant; Ionic liquids; Partitioning