皂化P204微乳体系萃取大豆蛋白的研究

研究了NaOH皂化P204/正辛烷微乳体系萃取大豆蛋白的机理和工艺,考察了大豆加入量、P204的浓度、NaOH的浓度、萃取时间、水相pH值及离子强度等对大豆蛋白萃取率的影响。实验结果表明,该微乳体系萃取大豆蛋白的优化工艺条件为:大豆粉与微乳液的质量体积比1∶10,P204在油相中浓度0.8 mol/L,NaOH的浓度1.25 mol/L,萃取时间15 min,外水相pH值5,萃取率可达88.48%。通过调节水相pH和离子强度可实现大豆蛋白的萃取和反萃取。     

油酸钠微乳液体系的结构参数和电导行为研究

本文用稀释法测定了油酸钠/醇/正庚烷/水四组分W/O型微乳液体系的结构参数:水内核半径Rw,颗粒有效半径Re,界面层厚度L,平均聚集数N,颗粒总数Nd,分散相总界面积Ad等结构参数和醇从连续相转移到界面的自由能△Goc-i。结果表明微乳液水内核半径Rw大小在纳米尺度;随含水量的增加,水内核半径Rw直线增加,而醇转移的界面自由能-△Goc-i减小,在含水量较低时微乳液的稳定性较强。对助表面活性剂的种类、内水相盐度变化对油酸钠微乳液电导率的影响进行了考察,结果表明使用正丁醇时形成电导渗滤体系,而使用正戊醇、异戊醇和正己醇时形成的是非渗滤体系;内水相中加入Na NO3对电导渗滤有抑制作用。醇碳链长度增加及适当的盐度有利于微乳液体系的稳定。     

非离子表面活性剂TWeen80相图的研究

本文研究了醇类（正丁醇、正戊醇、正辛醇和正癸醇）、油类（正十八烷、正十六烷、正十四烷、正十烷、正癸烷和正辛烷）、正十八烷含量以及NaCl浓度对Tween80／醇／油／水体系相图的影响。结果表明，NaCl浓度对Tween80／正辛醇／正十八烷／水体系相图的影响不明显；醇类随着炭原子数目的增加，O／W微乳液区面积增大，W／O微乳液区面积减小，微乳液区总面积增大；不同的油类形成的微乳液区面积由大到小的顺序是：正十六烷≈正十四烷＞正十二烷＞正癸烷＞正十八烷＞正辛烷；随着正十八烷含量的增加，微乳区面积减小。用2277热活性检测系统测定了石油菌B－2分别在非微乳液和助表面活性剂分别是正戊醇、正辛醇，油是正十八烷所形成的微乳液中生长的功率－时间曲线。结果表明微乳液培养基更适用于B－2利用高碳烷烃进行生长；正辛醇作助表面活性剂形成的微乳液培养基比正戊醇作助表面活性剂形成的微乳液培养更为有利；O／W型微乳液比W／O型微乳液对B－2的生长更为有利。     

柴油中相微乳液的制备和相图分析

制备了柴油/复合表面活性剂/正戊醇/MnCl2盐水五元微乳液;研究了MnCl2浓度、表面活性剂浓度及正戊醇浓度对五元微乳液体系中相微乳液的形成和鱼尾相图的影响.结果表明,用MnCl2扫描时形成的中相微乳液范围较窄;在鱼尾相图中,当复合表面活性剂D0821(双(C8-10烷基)二甲基氯化铵)和AEO-3(脂肪醇聚氧乙烯醚)的质量比为4∶6时,形成单相微乳液的表面活性剂效率最高,最佳表面活性剂的质量分数为8.3%.     

阴离子型表面活性剂所组成微乳液的异常流变性

对以正十六烷、油酸钾、正己醇和水所组成的微乳液进行研究,对其流变性和机理作了探讨.微乳液粘度和水油比变化的关系可用相转化来说明.层形结构区显示出有高粘度特征,并具有明显的负触变性现象.对此进行了讨论,并研究了pH值和盐类的影响.     

[Omim][BF_4]基离子液体微乳液萃取金属镧离子的研究

制备了OP-4+OP-7/苯甲醇/煤油/P204/[Omim][BF_4]/HCl微乳液体系,采用FTIR光谱以及表面张力方法对该微乳液体系的结构进行表征,并研究了该离子液体微乳液对La~(3+)的萃取行为,考察了不同的料液浓度、料液酸度、振荡时间、水乳比、温度等因素对La~(3+)萃取率的影响。结果表明:OP-4+OP-7/苯甲醇/煤油/P204/[Omim][BF_4]/盐酸体系中形成了W/O结构;少量的[Omim][BF_4]可对La~(3+)的萃取起到显著提升的作用,得到较高的萃取率;当水乳比为3∶1,振荡时间为8 min,料液浓度为0.004 mol·L-1,p H为3时,萃取率最高可达94.94%。     

他汀类药物在微乳液相色谱体系中的保留行为

以普伐他汀钠、阿托伐他汀钙、辛伐他汀和洛伐他汀为研究对象,考察了微乳液流动相中表面活性剂的浓度、油相浓度、助表面活性剂浓度以及流动相的pH值等对他汀类药物在微乳液相色谱体系中保留行为的影响。实验结果表明,微乳流动相中表面活性剂、助表面活性剂、亲脂性溶剂的浓度对他汀类药物保留行为的影响与理论模型一致;流动相的pH值对酸性他汀类药物保留行为的影响与理论模型基本一致,对中性他汀类药物保留行为的影响存在着隐函数关系。所建立的保留模型能较好地反映微乳液组成对他汀类药物保留行为的影响。     

皂化P204/煤油微乳体系分离L-苯丙氨酸的研究

研究了P204-煤油-NaOH组成的微乳液膜配方及其稳定性。通过该液膜体系对L-苯丙氨酸水溶液进行提取实验,考察了P204的浓度、乳水比、外水相pH值、膜相重复使用次数、分离时间等对提取效率的影响。实验结果表明,微乳液膜不仅稳定性好,无明显溶胀和泄漏,分离速度快,而且分离效果好,可自动破乳,油相可重复多次使用,对L-苯丙氨酸的一次性提取率达88.25%。     

四磺化酞菁钴在微乳液、醇－水体系中的二聚现象研究

采用分光光度法研究了四磺化酞箐钴（ＣｏＴＳＰｃ），在微乳液（ＴｒｉｔｏｎＸ－１００－壬烷－正戊醇－水）、醇－水（甲醇、乙醇、丙醇）体系中的二聚现象，计算了ＣｏＴＳＰｃ的二聚常数ＫＤ。结果表明，ＣｏＴＳＰｃ的二聚常数ＫＤ值随着微乳液中表面活性剂的浓度及醇－水溶液的介电常数的增加而减小     

四磺化酞菁钴在微乳液、醇-水体系中的二聚现象研究

采用分光光度法研究了四磺化酞菁钴（ＣｏＴＳＰｃ），在微乳液（ＴｒｉｔｏｎＸ－１００－壬烷－正戊醇－水）、醇－水（甲醇、乙醇、丙醇）体系中的二聚现象，计算了ＣｏＴＳＰｃ的二聚常数ＫＤ。结果表明，ＣｏＴＳＰｃ的二聚常数ＫＤ值随着微乳液中表面活性的浓度及醇－水溶液的介电常数的增加而减小。     

Extraction of europium by sodium oleate/pentanol/heptane/NaCl microemulsion system

The extraction of europium to a W/O microemulsion with an anionic surfactant was studied. In the sodium oleate (NaOL)/pentanol/heptane/NaCl system, the influence of aqueous-microemulsion ratio, concentration of NaOL, extraction temperature, concentration of cosurfactant, pH and salting-out agent on the extraction yield were investigated. Europium was probably extracted into the microemulsion phase in the form of Eu(OL)₂Cl, and the extraction yield (E%) was above 99% when R = 8. The enthalpy and entropy of Eu(III) extraction were calculated to be −12.18 kJ/mol and −61.41 J/(mol K), respectively. The back-extraction is conducted by hydrochloric acid (0.8 mol/L), which provided better back-extraction yields (95.15%).     

Extraction of rare earth metal samarium by microemulsion

The influence of the concentration of sodium oleate (NaOL), alcohol and the nature of the internal water phase on the water content of microemulsion was studied. The effect of the concentration of NaOL, sodium stearate, alcohol, salting-out agent, Alamine 336 added and of the contact time, volume ratio of the aqueous to microemulsion (R) and temperature on the extraction yield of samarium was investigated. The result shows that the extraction of samarium is effective under well-defined conditions utilizing WinsorII microemulsion systems.     

Effect of Interfacial Alcohol Concentrations on Oil Solubilization by Sodium Dodecyl Sulfate Micelles

Alcohol partitioning and its effect on oil solubilization in Winsor Type I microemulsion systems was investigated. The microemulsion systems consisted of sodium dodecyl sulfate (SDS), pentanol, isopropanol (IPA), and dodecane, with either deionized water or an aqueous solution of 50 mM CaCl(2). Alcohol partitioning between aqueous, oil, and interfacial phases of the microemulsion was described using a pseudophase model in which the alcohol was assumed to self-associate in the oil phase. Partitioning in these miroemulsions was consistent with pentanol self-association in the oil phase. IPA did not self-associate but co-associated with pentanol in the oil phase. IPA concentrations as high as 20 g/kg of water had no effect on pentanol partitioning. The partition coefficient for pentanol between aqueous and interfacial phases was about 220 on a mole fraction basis. However, pentanol saturated the interfacial phase at a mole ratio of 3 : 1 pentanol to SDS. Addition of pentanol beyond that sufficient to saturate the interface resulted in large amounts of pentanol partitioning into the oil, reaching concentrations in excess of 25 g dL(-1) of oil phase. Dodecane solubilization increased linearly with pentanol mole fraction in the interface up to the 3 : 1 pentanol-to-SDS saturation level. The fact that dodecane solubilization was unaffected by pentanol at concentrations beyond those necessary for interfacial saturation suggests that pentanol behaves as a cosurfactant and not a cosolvent in these microemulsion systems. Copyright 2000 Academic Press.     

Study of nano-emulsion formation by dilution of microemulsions

The influence of different dilution procedures on the properties of oil-in-water (O/W) nano-emulsions obtained by dilution of oil-in-water (O/W) and water-in-oil (W/O) microemulsions has been studied. The system water/SDS/cosurfactant/dodecane with either hexanol or pentanol as cosurfactant was chosen as model system. The dilution procedures consisted of adding water (or microemulsion) stepwise or at once over a microemulsion (or water). Starting emulsification from O/W microemulsions, nano-emulsions with droplet diameters of 20 nm are obtained, independently on the microemulsion composition and the dilution procedure used. In contrast, starting emulsification from W/O microemulsions, nano-emulsions are only obtained if the emulsification conditions allow reaching the equilibrium in an O/W microemulsion domain during the process. These conditions are achieved by stepwise addition of water over W/O microemulsions with O/S ratios at which a direct microemulsion domain is crossed during emulsification. The nature of the alcohol used as cosurfactant has been found to play a key role on the properties of the nano-emulsions obtained: nano-emulsions in the system using hexanol as cosurfactant are smaller in size, lower in polydispersity, and have a higher stability than those with pentanol.     

The effect of cosurfactants and the initiator concentration on the polymer to surfactant concentration in nanolatexes

The effect of cosurfactant and initiator concentration on the ab initio production of nanolatexes using low surfactant levels was investigated. While the use of cosurfactants (acrylic acid and pentanol) increased the amount of monomer that can be used in styrene‐SDS microemulsion formulations to 13 wt %, high surfactant concentrations are still required, resulting in polymer‐to‐surfactant ratios (Pol/Surf) <1. Latexes with particle size of 30 ± 5 nm were produced upon polymerization of these microemulsions. The Pol/Surf can be significantly increased by increasing the initiator concentration of emulsion polymerization recipes. Particle sizes are comparable with microemulsion latexes, however, less surfactant is required. The reduction in the particle size with higher initiator concentration is attributed to a higher efficiency of particle nucleation and to a higher nucleation rate relative to the rate of monomer transfer. Nanolatexes (particle size < 30 nm) were obtained with 19 wt % solids content and Pol/Surf of 3.6 in ab initio. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

ATMOSPHERIC OXIDATION OF VITAMIN C AND E IN THE SURFACTANT SYSTEM

The association of ascorbic acid (H₂A, AA) with α-tocopherol (α-T) enhances the antioxidant capability of the two vitamins in a microemulsion formed by water, pentanol and sodium dodecyl sulphate. The comparison of vitamin C oxidation kinetics in the presence and absence of α-T in the system shows that there are no tangible differences in the time of the ascorbic acid decomposition. The main effect is the enhancement of the H₂A oxidation with increased pentanol concentration in the system. Ascorbic anion interacts with surfactant association structures, changing W/O microemulsion towards O/W system. The polar part of H₂A is exposed to aqueous solution and subjected to oxidation.

For the vitamin C to vitamin E weight ratio equal 0.13, ascorbic acid stimulates α-T decomposition as long, as it does in the non-oxidised form. When not all amounts of both vitamins are decomposed their activity is similar to each other in the anionic surfactant system. It means they are both good antioxidants in W/O microemulsions. After some time, when vitamin C is completely decomposed, all these micellar systems become more stable with regard to vitamin E. Vitamin E occurs to be a better antioxidant in O/W microemulsion.     

Evaporation from microemulsions

The composition of W/O microemulsions during slow evaporation at room temperature and at 90°C was determined by chemical analysis. One series of microemulsions was stabilized by pentanol combined with sodium dodecyl sulfate, the other one was combined with hexadecyltrimethylammonium bromide.The hydrocarbon was styrene and the evaporation in the microemulsion was compared to that of the corresponding styrene/pentanol solutions.The results showed significant influence on the evaporation by the microemulsion structure; especially for water contents close to the minimum for stability     

Microemulsion structure in the lenticular monophasic areas of brine/SDS/pentanol/dodecane or hexane systems: electrochemical and fluorescent studies

The properties of pseudo-ternary systems involving brine, sodium dodecylsulfate (SDS), pentanol and dodecane or hexane have been investigated. When the hydrocarbon is dodecane, the microemulsion system includes in addition to the main monophasic area a small lens inserted in an oil-rich zone. With hexane, the microemulsion domain splits into two parts, one of which consists of a narrow scythe-blade shaped area which spreads from the water top up to compositions very rich in hydrocarbon. The properties of these uncommon microemulsions were compared with those of microemulsions belonging to the main monophasic area in order to gain additional understanding of their structure. Results of experiments including electrical conductivity and viscosity measurements, electrochemical and fluorescent probe studies lead to the following conclusions: Microemulsions of the small lens of the brine/SDS/pentanol/dodecane system exhibit properties which are reminiscent of structures with at once water and oil countinuous phases. Microemulsions of the lenticular area of the brine/SDS/pentanol/ hexane system seem to undergo the same structural transitions as microemulsions of systems which present a single monophasic area: water-continuous, bicontinuous and oilcontinuous structures.     

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.