Solvent extraction of thorium(IV) using W/O microemulsion

The extraction of thorium(IV) was investigated using two types of W/O microemulsion,one of which was formed by a surface-active saponified extractant sodium bis(2-ethylhexyl) phosphate(NaDEHP) and the other was formed by a mixture of an anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate(AOT) and an extractant bis(2-ethylhexyl)phosphoric acid(HDEHP) as the cosurfactant.The extraction capacities of the above two systems were higher than that of the HDEHP extraction system.High concentration of NaNO 3 showed no influence on the extraction in the NaDEHP based W/O microemulsion system,whilst reduced the extractability in the AOT-HDEHP W/O microemulsion system.The mechanism in acidic condition was demonstrated by the log-log plot method.The structure of the aggregations and the water content in the organic phase after extraction were measured by dynamic light scattering and Karl Fischer water titration,respectively.It was found that NaDEHP based W/O microemulsion broke up after extraction,while AOT-HDEHP W/O microemulsion was reserved.     

Selective separation and enrichment of proteins in aqueous two-phase extraction system

A simple aqueous two-phase extraction system(ATPS) of PEG/phosphate was proposed for selective separation and enrichment of proteins.The combination of ATPE with HPLC was applied to identify the partition of proteins in two phases.Five proteins (bovine serum albumin,Cytochrome C,lysozyme,myoglobin,and trypsin) were used as model proteins to study the effect of phosphate concentration and pH on proteins partition.The PEG/phosphate system was firstly applied to real human saliva and plasma samples,some pro...     

Resolution of α-cyclohexyl-mandelic acid enantiomers by two-phase (O/W) recognition chiral extraction

This paper presents a new chiral separation technology: two-phase (O/W) recognition chiral extraction. Distribution behavior of α-cyclohexyl-mandelic acid enantiomers was studied in the extraction system with D(L)-isobutyl tartrate in 1,2-dichloroethane organic phase and β-CD derivatives in aqueous phase, and the influence of the kind and concentration of extractant and pH on extraction performance was investigated. The experimental results indicate that two-phase (O/W) recognition chiral extraction is of strong chiral separation ability. HP-β-CD, HE-β-CD and Me-β-CD have higher recognition ability for S-CHMA than that for R-CHMA, among which HP-β-CD has the strongest ability; whereas, D-isobutyl tartrate has reversed recognition ability for them. In the extraction system containing HP-β-CD and D-isobutyl tartrate, e.e.% of S-CHMA in aqueous phase reached 27.6% by one stage extraction, and the distribution ratio for R-CHMA(kR) and for S-CHMA(kS) and separation factor (α) are 2.44, 0.89 and 2.49, respectively. Meanwhile, pH and concentration of extractant have great effects on chiral separation ability. Two-phase (O/W) recognition chiral extraction has great significance for preparative separation of racemic compounds.     

Studies on the Hydrogen Bonding Network Structures of Amino-konjacglucomannan-zinc Chelate

Amino-Konjacglucomannan(NH2-KGM) was prepared through the reaction of ammonium hydroxide with KGM by ultrasonic. The influence of amount of ammonium hydroxide, concentration of KGM and ultrasonic time on the extent of amination was studied. Then, NH2-KGM and zinc sulfate were used as materials for the preparation of NH2-KGM-Zn complex. The results indicated that the extent of amination increases with increasing the ammonium hydroxide. The optimum concentration of KGM and ultrasonic time are 0.3% and 75 min respectively. IR showed KGM is successfully aminated and NH2-KGM forms stable complex with zinc(Ⅱ). The hydrogen bonding network structures of NH2-KGM-Zn are more stable and the key linking points of hydrogen bonding network are at the OH(6) and O(3) positions of mannose and OH(2) of glucose and O(3) of mannose on the KGM ring. It is more favorable for NH2-KGM-Zn to form intermolecular hydrogen bonds between KGM.     

正辛烷为稀释剂不对称N-甲基-N-辛基烷基酰胺萃取铀(Ⅵ)的研究(英)

The extraction of uranyl nitrate was studied with newly synthesized unsymmetrical alkylamides, Nmethyl-N-octyloctylamide (MOOA), N-methyl-N-octyldecanamide (MODA), and N-methyl-N-octyldodecanamide (MODOA), employing n-octane as diluent. The effect of the concentrations of nitric acid, sodium nitrate and extractants on the extraction was investigated and the extraction mechanism was suggested. The effect of temperature on the extraction was also studied and the related thermodynamic functions were calculated. The extracted species were characterized by FTIR spectrometry。     

STRUCTURE-REACTIVITY STUDIES ON THE EXTRACTION OF RARE EARTHS BY DIALKYL ISOPROPYLPHOSPHONATES

Dialkyl isopropylphosphonates with various alkyl groups are synthesized for the structure-reactivity studies on the extraction of rare earths. Steric effect of ligands on the extrac-tion behaviour of rare earth is well demonstrated due to the lanthanide contraction. Thethermodynamic functions of the extraction reaction are estimated and the influence of chem-ical structure of extractants is discussed. By the method of continuous variation as well asthe elementary analysis, the composition of the extracted species is deduced as Ln(NO_3)_3·3L.The structure of the coordination compound is further elucidated by IR and NMR spectra.The magnetic property and the differential thermal analysis of the complexes are also studied.     

GRAFTING OF POLYSTYRENE ONTO A NANOMETER SILICA SURFACE BY MICROEMULSION POLYMERIZATION

The grafting of polystyrene onto a nanometer silica surface by microemulsion polymerization is described. Silicawas functionalized with 3-methacryloxypropyltrimethoxysilane coupling agent before polymerization. A mixture of ionic andnon-ionic surfactants as well as water-soluble and oil-soluble initiators were used. The effect of the amount of silica and ionicsurfactant on the graft polymerization was studied. The graft polymerization procedure for styrene was also applied to methylmethacrylate. Composite particles with a core-shell structure were obtained and the yield and grafting efficiency of monomerwere high.     

Dispersive Liquid-liquid Microextraction for Simultaneous Determination of Six Parabens in Aqueous Cosmetics

A simple and rapid sample preparation method of dispersive liquid-liquid microextraction（DLLME） was applied in the simultaneous determination of six parabens in the aqueous cosmetics. The analysis was performed on gas chromatography coupled with a flame ionization detection（GC-FID）. The mixed solution containing 30 μL of chloroform（extraction solvent） and 300 μL of tetrahydrofuran（dispersive solvent） was rapidly injected into the sample solution for the purpose of microextraction. After that, the solution mentioned above was centrifuged at 4000 r/min for 10 min, and then the organic sediment phase was detected by GC-FID. The effects of experimental parameters, such as the extraction solvent and the volume of it, and the dispersive solvent and the volume of it, on the yield of the extraction were studied in detail. Under the optimum conditions, the enrichment factors of the target analytes range from 87 to 214. Linearity ranges are 0.05-10.0μg/mL for methylparaben and 0.025--5.0 μg/mL for the other five parabens. The relative standard deviations（RSDs） are lower than 8.2%（n=6）. The proposed method was applied to the analysis of six parabens in eleven aqueous cosmetics. The recoveries of the target analytes in the spiked real samples are in the range of 81.0%-103%.     

Studies on the Phenylfluorone-Mo(Ⅵ) Complex as Interacting Mode Spectroscopic Probe of Protein in OP Microemulsion Medium

The application of phenylfluorone (PF)-Mo(VI) complex as a spectroscopic probe is studied. In the presence of OP microemulsion at pH 3.04, PF-Mo(Ⅵ) complex combines protein rapidly to form a stable compound and the absorbance at 527 nm is in proportion to the concentration of protein in the range 0-16 μg mL-1 for bovine serum albumin (BSA). OP microemuslion media is introduced into protein determination, it has increased markedly the sensitivity of the system. The molar absorption coefficient was 5.98×l06 L mol-1 cm-1 for BSA. The assay, with sensitivity, simplicity and tolerance to many foreign substances, is applied to the determination of protein in samples with satisfactory results. Moreover, the binding number of BSA with the complex, which is determined by molar ratio and slope ratio methods, is in good agreement.     

Comparison Between Catalytic Activity and Activity Changes During Denaturation by Guanidine Hydrochloride of Enzymes in Crystalline State and in Solution

The catalytic activity and activity changes during denaturation by guanidine hydrochloride of glyceraldehyde-3-phosphate dehydrogenase,lactate dehydrogenase and α-chymotrypsin in crystalline state and in solution have been compared.The catalytic activities are lower in crystalline state than in solution. Enzymes in crystalline state are more stable than in solution during denaturation by guanidine hydrochloride.Ammonium sulfate has different effects on catalytic activities of different enzymes and shows protection on all enzymes studied during denaturation by guanidine hydrochloride.The protection is more obvious at high concentrations of guanidine hydrochloride than at low concentrations.It is suggested that the flexibility or mobility of enzyme is required for the catalytic activity and related to the stability of enzymes. Enzymes with less flexibility or mobility are more stable.     

Extraction of cobalt(Ⅱ) from aqueous solution by N,N'-carbonyl difatty amides

The development of economic and environmentally friendly extractants to recover cobalt metal is required due to the increasing demand for this metal.In this study,solvent extraction of Co(Ⅱ) from aqueous solution using a mixture of N,N’-carbonyl difatty amides(CDFAs) synthesised from palm oil as the extractant was carried out.The effects of various parameters such as acid,contact time,extractant concentration,metal ion concentration and stripping agent and the separation of Co(Ⅱ) from other metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ) were investigated.It was found that the extraction of Co(Ⅱ) into the organic phase involved the formation of 1:1 complexes.Co(Ⅱ) was successfully separated from commonly associated metal ions such as Fe(Ⅱ),Ni(Ⅱ),Zn(Ⅲ) and Cd(Ⅱ).Co(Ⅱ) stripping from the loaded organic phase was studied in aqueous solution.These results are useful to recover Co(Ⅱ) from aqueous solution utilising(CDFAs) as an extractant.     

TRANSFER MECHANISM OF QUININE DRUG ACROSS THE OIL/WATER (O/W) INTERFACE

The transfer phenomena of quinine drug at the aqueous 1,2- dichloroethane (DCE)interface have been studied by the current- scanning polarography. The relationships be-tween the wave height and pH of aqueous phase, concentration of quinine as well as therate of water drop are discussed. The effect of supporting electrolyte, buffer solution andthe nature of organic solvent on the polarographic wave is studied. The transfer char-acteristics of quinine in aqueous phase and in organic phase are compared, The mono- pro-tonated and diprotonated quinines can both transfer at the interface so as to produce twopolarographic waves. The transfer process of quinine at the interface is simultaneouslycontrolled by diffusion and reestablishment of the disturbed protonated equilibrium ofquinine. A further investigation is made by chronopotentiometry. On the basis of thetheoretical analysis, the formulae of the limiting current are derived and discussed. Thetheoretical results are in agreement with the experimental ones.     

Preconcentration and Determination of Copper（Ⅱ） Using Octadecyl Silica Membrane Disks Modified by 1,5-Diphenylcarhazide and Flame Atomic Absorption Spectrometry

A simple and reproducible method for the rapid extraction and determination of trace amounts of copper（Ⅱ） ions using octadecyl-bonded silica membrane disks modified by 1,5-diphenylcarbazide （DPC） and atomic absorption spectrometry was presented, which was based on complex formation on the surface of the ENVI-18 DISK^TM disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution was efficient and quantitative. The effect of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to be about 1000 mL providing a preconcentration factor of 400. The maximum capacity of the disks was found to be （255±5） lag for Cu^2＋, and the limit of detection of the proposed method was 5 ng per 1000 mL. The method was applied to the extraction and recovery of copper in different water samples.     

Effects of the chemical structure of surfactants on the stability of naphthenic oil-based metalworking fluids

In this study,various nonionic surfactants(NS) with different ethylene oxide(EO) numbers and tail lengths and its binary blends with anionic surfactants(AS) were used as emulsifiers for naphthenic oil to form the microemulsion metalworking fluids(MWFs),and the effects of them on the stability of the emulsion system were investigated by formulation triangle method.The results indicated that binary complex surfactants of NS and AS as emulsifiers exhibited better emulsifying effect than that of single NS.NS with different EO numbers and tail lengths presented various emulsifying effects.NS(EO=10)exhibited the greatest number of stable formulations,especially the TX-10,but no linear relationship existed between the number of stable formulations and the tail length of NS.In addition,aromatic primary alcohol ethoxy late(APAE) series surfactants containing benzene groups similar to the cycloalkanes in the naphthenic oil so that presented the best emulsifying affect and the greatest number of stable formulations.The co-surfactant of sodium dodecyl benzene sulfonate(SDBS) binary blends with NS exerted the best synergistic effect,and the stable formulations numbers were ranged from 5 to 7,next sodium stearate(SS) comes last followed by sodium dodecyl sulfate(SDS-1) and sodium dodecyl sulfonate(SDS-2).     

N，N′-二甲基-N，N′-二辛基丙二酰胺萃取铀(Ⅵ)的研究

The novel unsymmetrical extractant N，N′-dimethyl-N，N′-dioctylmalonamide (DMDOMA) was prepared by reaction of diethyl malonate with N-methyl octanamine. The extraction mechanism and the behavior of uranyl nitrate with DMDOMA employed cyclohexane as diluent were studied. The effects of concentrations of nitric acid, sodium nitrate, extractant and also the temperature on the extraction were considered. The stoichiometry of the extracted species is and the coordination of extracted species was suggested based on the IR data. The value of ΔH of extraction is -26.9 ± 0.80 kJ·mol^-1. The value of the apparent extraction constant is 133.88 ± 17.92, which shows that the optimization of extractant structure improves the extractability of malonamide for uranyl nitrate.     

STUDIESOF MOLECULAR REORIENTATION OF A NON-SPHERICAL MOLECULE IN THE LIQUID STATE BY DEPOLARIZED RAYLEIGH SCATTERING

Effects of orientational pair correlations on the reorientationrate of non-spherical molecules are studied.The Keyes-Kivelsonequation for the coherent light scattering relaxation time isderived using a different technique.Experimental data on thecoherent light scattering relaxation time and the single parti-cle reorientation for n-butanol are obtained as a function ofthe concentration of n-butanol.The results are compared withthe Stokes-Einstein-Debye equation and are discussed in termsof the orientational pair correlation effect.     

Effect of Addition of Cosurfactant on the Phase Behaviour of Oil-in-water Aminosilicone Oil Microemulsion

Stable and transparent aminosilicone oil microemulsion of the average particle size below 0.05 micron was prepared. The interaction of the aminosilicone oil, water, complex surfactants and cosurfactant was studied by part pseudotemary phase diagram. The effect of cosurfactants (such as alcohol) and the mechanism of its effect on the phase behaviour of the pseudotemary system were investigated.     

Modeling phase equilibria of semiclathrate hydrates of CH_4,CO_2 and N_2 in aqueous solution of tetra-n-butyl ammonium bromide

Semiclathrate hydrates of tetra-n-butyl ammonium bromide(TBAB) offer potential solution for gas storage,transportation,separation of flue gases and CO2 sequestration.Models for phase equilibria for these systems have not yet been developed in open literatures and thus require urgent attention.In this work,the first attempt has been made to model phase equilibria of semiclathrate hydrates of CH4,CO2 and N2 in aqueous solution of TBAB.A thermodynamic model for gas hydrate system as proposed by Chen and Guo has been extended for semiclathrate hydrates of gases in aqueous solution of TBAB.A correlation for the activity of water relating to the system temperature,concentration of TBAB in the system and the nature of guest gas molecule has been proposed.The model results have been validated against available experimental data on phase equilibria of semiclathrate hydrate systems of aqueous TBAB with different gases as guest molecule.The extended Chen and Guo's model is found to be suitable to explain the promotion effect of TBAB for the studied gaseous system such as,methane,carbon dioxide and nitrogen as a guest molecule.Additionally,a correlation for the increase in equilibrium formation temperature(hydrate promotion temperature,ΔTp) of semiclathrate hydrate system with respect to pure gas hydrate system has been developed and applied to semiclathrate hydrate of TBAB with several gases as guest molecules.The developed correlation is found to predict the promotion effect satisfactorily for the system studied.     

微乳液合成胶体CuO/γ-Al2O3及其催化芳香硝基化合物还原（英文）

Monodispersed colloidal copper oxide nanoparticles were synthesized by water-in-oil microemulsion using CuCl 2·H2O and NaOH.The effect on CuO particle size was studied by varying the water-to-surfactant molar ratio,precursor concentration and molar ratio of NaOH to CuCl2.The morphology,size and size distribution of the particles were studied by transmission electron microscopy and dynamic light scattering.Dispersion destabilization of the colloidal copper oxide nanoparticles was detected by a Turbiscan apparatus.CuO/γ-Al2O3 catalysts were prepared by dispersing highly stable CuO nanoparticles on γ-alumina by mechanical stirring.The catalysts were analyzed by scanning electron microscopy,transmission electron microscopy,X-ray photoelectron,and X-ray diffraction,which confirmed the uniform dispersion of CuO on the support.The reduction of the nitro aromatic compounds,4-nitrophenol,3-nitrophenol,and 2-nitrophenol,were studied.The CuO/γ-Al2O3 catalysts were active for the reduction of these nitro aromatic compounds.     

Electrochemical Oxidation of L-Cystenine in SDS／BA／H2O Microemulsion

The electrochemical oxidation of L-cysteine in an SDS/BA/H2O microemulsion system was studied with the methods of ultramicroelectrode cyclic voltammetry and AC impedance. The catalytic efficiency of the microemulsion on the electrochemical oxidation increases with the increase of BA or SDS content, but decreases with the increase of the water content because of the effects of BA, SDS and water on the solubilization of Lcysteine in the microemulsion. Furthermore, the catalytic efficiency of the bicontinuous structure is greater than that of an O/W microemulsion system. The results derived from both the rate constant k^0 and Gibbs free energy △G^≠ accord with those from the catalytic efficiency.