Co-reporter:Lei-Lei Chen;Fen-Fang Li;Zhi-Jian Tan
Chemical Papers 2015 Volume 69( Issue 11) pp:1465-1472
Publication Date(Web):2015 November
DOI:10.1515/chempap-2015-0162
In this paper, an ionic liquid-based aqueous two-phase system (ILATPS) was applied to the chiral separation of α-cyclohexylmandelic acid (α-CHMA) enantiomers with hydroxypropyl-β-cyclodextrin (HP-β-CD) as the chiral selector. Several influencing parameters were investigated including the types and concentration of ionic liquids, the amount of phase-forming salt, temperature, mixing time, pH, and the content of HP-β-CD. The results showed that not all ILATPS had the ability to chirally recognise the selected enantiomers and that [C4mim]BF4/(NH4)2SO4-based ATPS possessed the best enantioseparation ability of the investigated ILATPSs. Under optimal conditions, the separation factor (α) attained 1.59 in a single-step extraction. ILATPS is much “greener” than other liquid-liquid extraction systems, showing its potential for application to the chiral separation.
Co-reporter:Fen-Fang Li;Zhi-Jian Tan;Zhi-Feng Guo
Chemical Papers 2014 Volume 68( Issue 11) pp:1539-1545
Publication Date(Web):2014 November
DOI:10.2478/s11696-014-0594-y
An alcohol/salt-based aqueous two-phase system (ATPS) was employed for enantioseparation of (R,S)-mandelic acid (MA) and (R,S)-α-cyclohexylmandelic acid (α-CHMA). Sulfonated β-cyclodextrin (Sf-β-CD) with different degrees of substitution (DS) was considered as the chiral selector. The ethanol/(NH4)2SO4 system showed the optimal chiral recognition ability for MA. To optimize the experimental conditions, Sf-β-CD concentration, ethanol and salt concentration, temperature, and pH were studied. The recognition ability of enantiomers was mainly dependent on the type of the chiral selector but the ethanol and (NH4)2SO4 concentrations also had significant influence on the enantiomeric recognition. The maximum values of α and eeup of 1.69 and 16.3 % were obtained, respectively, for MA under the optimal conditions. A potential application of this alcohol/salt ATPS is the scale-up of chiral separation of MA.
Co-reporter:Zhijian Tan, Fenfang Li, Xuelei Xu
Separation and Purification Technology 2012 Volume 98() pp:150-157
Publication Date(Web):19 September 2012
DOI:10.1016/j.seppur.2012.06.021
To explore mild and efficient techniques for separation and purification of the active ingredients in natural plants is still ongoing. Ionic liquid (IL) is a new class of molten salts that are liquid at ambient temperature, which has many unique properties is safe and environmentally friendly chemical. Aqueous two-phase systems (ATPSs) based on ILs and salts were applied to isolate and purify anthraquinones (AQs) from aloe leaves. The main affecting parameters on the partitioning behavior and extraction efficiency were investigated through the partitioning process: type and mass of salt, pH, extraction temperature, and equilibrium time of the systems. Aloe AQs preferentially migrated into the IL-rich phase. Under the optimal conditions, the maximal extraction efficiency 92.1% of total AQs was obtained with the [C4mim]BF4/Na2SO4 system at 25 °C and pH 4.0. The reverse extraction experiments were done by adjusting pH with IL being recycled. Furthermore, the major constituents of aloe-emodin and chrysophanol were analyzed by a HPLC method. Ionic liquid-based ATPSs (ILATPSs) are great candidates for the replacement of volatile organic compounds in typical liquid–liquid extraction. This proposed extraction technique opens up new possibilities in purification of other active ingredients in natural plants or biologic samples.
Co-reporter:Jian-min Xing ;Fen-fang Li
Journal of Chemical Technology and Biotechnology 2012 Volume 87( Issue 3) pp:346-350
Publication Date(Web):
DOI:10.1002/jctb.2720
Abstract
BACKGROUND: R-mandelic acid is an important chiral pharmaceutical intermediate, which is commonly obtained by biotransformation. This work has focused on using novel chiral recognition technology, aqueous two-phase extraction, for the chiral separation of mandelic acid.
RESULTS: The copper (II) formed a 2:1 complex with β-CD in an alkaline solution, which was isolated from solution by the addition of ethanol. The complex structure was characterized by IR and UV spectroscopy. The chiral recognition system was established by adding Cu2-β-CD into the triton-114 aqueous two-phase extraction system, which preferentially recognizes the (R)-enantiomer rather than the (S)-enantiomer. Factors affecting the extraction mechanism were analyzed, namely the concentration of Cu2-β-CD and tritonX-114, the types of salts, pH, and temperature. It was found that the concentration of Cu2-β-CD and temperature were the most important influencing factors for chiral separation of mandedlic acid. The experimental results showed that the ee values increased with pH and concentration of trition-114, and the maximum ee was 67.91%. The addition of inorganic salt had a strong influence on ee, which decreased when salt was added into the aqueous two-phase extraction system.
CONCLUSION: A novel chiral recognition technology - aqueous two phase extraction is reported in this paper.The tritonX-114 aqueous two phase system have a good recognition ability for mandelic acid. Copyright © 2012 Society of Chemical Industry
Co-reporter:Zhi-jian Tan 谭志坚;Fen-fang Li 李芬芳
Journal of Central South University 2012 Volume 19( Issue 8) pp:2136-2141
Publication Date(Web):2012 August
DOI:10.1007/s11771-012-1256-2
A novel cloud-point extraction (CPE) was successfully used in preconcentration of biphenol A (BPA) from aqueous solutions. Majority of BPA is extracted into the surfactant-rich phase. The parameters affecting the CPE such as concentration of surfactant and electrolyte, equilibration temperature and time and pH of sample solution were investigated. The samples were analyzed by high-performance liquid chromatography with ultraviolet detection. Under the optimized conditions, preconcentration of 10 mL sample gives a preconcentration factor of 11. The limit of detection (LOD) and limit of quantification (LOQ) are 0.1 μg/L and 0.33 μg/L, respectively. The linear range of the proposed method is 0.2–20 μg/L with correlation coefficients greater than 0.998 7 and the spiking recoveries are 97.96%–100.42%. The interference factor was tested and the extraction mechanism was also investigated. Thus, the developed CPE has proven to be an efficient, green, rapid and inexpensive approach for extraction and preconcentration of BPA from water samples.
Co-reporter:Jian-min Xing;Fen-fang Li
Applied Biochemistry and Biotechnology 2009 Volume 158( Issue 1) pp:11-19
Publication Date(Web):2009/07/01
DOI:10.1007/s12010-009-8641-9
A two-step process was developed for the purification of polysaccharides from the pulp of Aloe varavia using aqueous two-phase system (ATPS) extraction and a novel copolymer ultrafiltration membrane. The first step was ATPS under optimal separations conditions using a total composition of 18% PEG2000, 25% ammonium sulfate, pH 3.0, and 0.3 M NaCl. To form the copolymer membrane, poly(acrylonitrile-acrylamide-styrene) was prepared by solution polycondensation using azoisobutyronitrile as initiator. Then, membranes were formed from the dissolved copolymer by the phase inversion method. Copolymer structure was investigated by infrared spectrum and thermogravimetric analysis (TGA). The copolymer membrane surface and cross section were observed by scanning electron microscopy. The water flux of this membrane was 26.33 mL/(cm2 h), and retention was 96% for bovine serum albumin and 34% for dextran T40000. The separation and purification of aloe polysaccharide were carried using this copolymer membrane following ATPS. The TGA of aloe polysaccharide demonstrated a high purity of the polysaccharide. By gas chromatographic analysis, it was shown that mannose is the main monosaccharide in the aloe polysaccharide, and only a few glucose residues are present.
![2-Propenoic acid,2-methyl-, 6-[(4'-cyano[1,1'-biphenyl]-4-yl)oxy]hexyl ester](http://img.cochemist.com/ccimg/117400/117318-91-9.png)
![2-Propenoic acid,2-methyl-, 6-[(4'-cyano[1,1'-biphenyl]-4-yl)oxy]hexyl ester](http://img.cochemist.com/ccimg/117400/117318-91-9_b.png)
