超临界二氧化碳微乳液的研究和应用进展

综述了在超临界二氧化碳（SFC）中，能形成微乳液的表面活性剂（SAA）的结构特性，助SAA对SFC微乳液形成的影响以及SFC微乳液的研究现状，同时，介绍了紫外－可见吸收光谱、傅立叶－红外光谱、小角中子散射和小角X光散射等近代测试方法，及其在SFC微乳液形成及其结构特性研究中的应用。另对SFC微乳液在化学反应，生物活性物质及金属离子萃取，合成材料和清洗领域中的应用也进行了介绍。     

超临界CO2微乳液及其在纺织中的研究进展

基于超临界CO_2流体基本性质,介绍了超临界CO_2微乳液的形成原理和评价指标。重点总结了超临界CO_2微乳液中含氟表面活性剂和碳氢表面活性剂的研发现状;综述了超临界CO_2微乳液体系在纺织领域中的最新应用进展,得出了其在纺织材料前处理、染色、后整理及纤维改性等清洁化加工上的应用价值;并指出可以通过加强超临界CO_2微乳液基础理论研究和超临界CO_2/离子液体微乳液体系构建,拓宽其在纺织、材料、化学、生物等领域的应用范围。     

离子液体表面活性剂的合成与应用(XII)——微乳液

离子液体表面活性剂替代传统表面活性剂构建微乳液具有明显的优势,且结构可设计;所制备的微乳液分为单相微乳液和多相微乳液,其相图主要包括拟三元相图和“鱼状”相图;微乳液的微观结构,如液滴尺寸、相互作用或极性等,可通过电化学技术、动态激光散射、小角X射线散射等技术来确定。此类微乳液可广泛应用于纳米粒子制备、聚合反应、金属离子萃取等领域。     

二氧化碳包水的微乳液可做为包括蛋白质的亲水物的溶体（英）

全氟聚醚碳酸铵表面活性剂用在超临界ＣＯ２之中形成微乳液，使非挥发的亲水蛋白质可以溶解在这种ＣＯ２流体之中。用四种光谱技术证实了这种微乳液滴的特性与水的特性相近，并为合成具有该牧场生的表面活性剂提出模式。     

柴油微乳液研制及影响因素的考察

利用非离子型表面活性剂复配制备W/O柴油微乳液,并以油、水、表面活性剂 助表面活性剂为三组分做出相图。通过微乳液相区面积考察不同因素对制备柴油微乳液的影响。因素包括不同表面活性剂的复配,不同的助表面活性剂及助表面活性剂与表面活性剂的比(m(C)∶m(T))。并用不同浓度的碱液代替水相,考察碱液对柴油微乳液形成的影响。结果表明最佳实验条件为:表面活性剂复配比为0.667,m(C)∶m(T)=0.3,助剂为正丁醇,碱液质量分数为0.1%。利用HLB值理论和界面膜理论对实验结果进行了分析。     

超临界二氧化碳用表面活性剂的研究进展

综述了超临界二氧化碳用表面活性剂的结构特征及其研究现状,并按结构特征分类介绍了含有机氟、有机硅、聚醚等可溶于二氧化碳片断的表面活性剂及其与助表面活性剂组成的具有表面活性的体系,给出了典型表面活性剂在超临界二氧化碳中的应用实例。     

双尾表面活性剂/盐水溶液/正辛烷三元体系相态特性的研究

研究了在不加助表面活性剂的情况下,双尾表面活性剂盐水溶液和正辛烷组成的三元体系中能否形成中相微乳液及其相关的相态特性。结果表明,在不加助表面活性剂的情况下,双尾表面活性剂CmGA(EO)nS(m=12,14,16;n=0,1,3,4,8)中,只有C14GA(EO)nS(n=1,3,4)可与盐水及正辛烷形成中相微乳液;以适宜的增溶参数、低界面张力值以及相体积图为基础所确定的形成中相微乳液的最佳含盐量三者一致性较好;随着C14GA(EO)nS(n=1,3,4)中EO基团数增加,形成中相微乳液的最佳盐度和增溶参数皆随之增加,而最佳界面张力值则降低。     

NMR方法在表面活性剂溶液研究中的应用

通过近年来ＮＭＲ方法在表面活性剂溶液研究中的具体应用实例，介绍了微乳液体体系各组分自扩散系数的ＮＭＲ测量和微乳液结构关系；表面活性剂溶液相图的ＮＭＲ确定；表面活性剂溶液增溶平衡和增溶作用ＮＭＲ研究等结果。     

微乳液在溶剂萃取分离中的应用研究进展

综述了用微乳液法萃取分离水中的非离子有机污染物、重金属离子和在湿法冶金工业中萃取分离金属离子的研究进展。表面活性剂、助表面活性剂、油和水形成WinsorⅡ或WinsorⅢ型微乳液,非离子有机污染物和金属离子进入微乳液的双连续区域或者是W/O型的微乳液中,从而实现水和有机物或金属离子的分离。对影响微乳液萃取的因素如助表面活性剂、助表面活性剂与表面活性剂的比率(nC/nS)和盐度等进行了论述。     

烷基聚葡糖苷表面活性剂形成微乳液的研究

以烷基聚葡糖苷(APG或CiGi)为表面活性剂，C4～C6正构醇为助表面活性剂，采用肉豆蔻酸异丙酯为油相，与水一起得到微乳液体系。研究了在不同烷基链长度的醇作用下，不同烷基碳链长度的烷基聚葡糖苷形成微乳液体系的拟三元相图以及δ—γ相图，并用HLB方程计算了微乳液界面的一些重要参数。发现使用较长碳链的醇以及用较长碳链的APG均有利于单相及中相微乳液的形成，并对此进行了解释，同时确定了单相微乳液效率最高的体系。     

超临界CO2微乳体系及其应用

论述了超临界CO2微乳体系的基本原理,重点对表面活性剂在超临界CO2中形成微乳的机制进行了总结。同时介绍了超临界CO2微乳体系在金属离子萃取、生物活性分子的提取、化学反应、合成纳米材料及染色等方面的应用,并展望了该技术的发展趋势。     

Molecular dynamics simulation of supercritical CO2 microemulsion with ionic liquid domains: Structures and properties

Supercritical carbon dioxide microemulsions are great medium to combine two immiscible substances through forming nanoscale polar cores in nonpolar continuous phase with the help of proper surfactants. The properties of microemulsions could be significantly affected by their constituents and structures. In this work, molecular dynamics simulation was implemented to study supercritical carbon dioxide microemulsions containing ionic liquid[bmim] [PF₆] and water by adding surfactant Ls-36. Results showed that the above components could form spherical aggregates in CO₂ bulk phase with[bmim] [PF₆] and some water as the inner core, surfactant headgroups and water as the intermediate shell, and surfactant tails as the outer shell. The microstructure information about the outer shell was further investigated by defining an angle between the surfactant tail and the normal direction of the aggregate outer surface, which ranged from 78° to 125°. The influence of the ionic liquid content on the size and structure of microemulsions was explored and the best molar ratio between the ionic liquid and surfactant was around 1.25 for getting maximum water solubility.     

In situ optical monitoring of the solution concentration influence on supercritical particle precipitation

We report a novel approach for the measurement of the location of particle formation in the supercritical antisolvent process (SAS). The measurement strategy is based on in situ Raman and elastic light scattering. In the SAS process, paracetamol was used as the solute, ethanol as the solvent and carbon dioxide as the antisolvent. Experiments were performed under miscible conditions for the binary system ethanol and carbon dioxide at 313 K and pressures between 10 MPa and 17.5 MPa. For high paracetamol concentrations in the injected ethanol solution, particles were found to start precipitating after jet breakup in a multi-phase flow. For low paracetamol concentrations, precipitation starts later in a one-phase flow, when the transient interface (phase boundary) between the injected solution and the supercritical carbon dioxide has diminished.     

Dyeing poly(lactic acid) fibres in supercritical carbon dioxide

A study has been conducted into the dyeing of poly(lactic acid) fibres in supercritical carbon dioxide. The fibres were completely dyed using disperse dyes at 50 °C as shown by fibre cross-sections, although high colour depths in dark shades still prove challenging. Dye uptake increased significantly at temperatures ≥80 °C. At 95 °C in supercritical carbon dioxide, shrinkage and hardening of raw poly(lactic acid) were observed which could partly be overcome by the supercritical carbon dioxide extraction step. Afterclearing with cold supercritical carbon dioxide (to remove unfixed dye after dyeing) decreased the colour depth and led to non-uniform dyeing results on poly(lactic acid). Wash and rub fastness was good to very good also when poly(lactic acid) was not aftercleared in supercritical carbon dioxide. Fibre damage and elongation at break in supercritical carbon dioxide were similar to water.     

Molecular modeling and experimental verification of lipase-catalyzed enantioselective esterification of racemic naproxen in supercritical carbon dioxide

Experimental and simulation analyses were performed on the lipase-catalyzed esterification reaction of racemic naproxen by CALB (candida antarctica lipase B) enzyme in supercritical carbon dioxide. The reaction pathways were investigated by quantum mechanical analysis, and the enantioselectivity of the products was predicted by molecular dynamics simulation analysis. Calculated results from molecular modeling in supercritical carbon dioxide were qualitatively compared with experimental data by using racemic naproxen as a substrate. All molecular modeling results and experimental data were acquired and compared with those in ambient and supercritical condition. Moreover, to verify the stability of enzymatic reaction in each solvent condition, reaction pathways were investigated in several solvent conditions (vacuum, water, hexane and supercritical carbon dioxide), and the stability of enzymatic reaction in supercritical carbon dioxide was compared with other solvent conditions. This paper is dedicated to Professor Chul Soo Lee on the occasion of his retirement from Korea University.     

Gas mass transfer to AOT-based microemulsions

The present paper analyses the gas/liquid mass transfer process employing carbon dioxide as gas phase and ternary water in oil microemulsions as absorbent liquid phases. The liquid phases were obtained by a direct mixing of water, 2,2,4-trimethylpentane and sodium bis(2-ethylhexyl)sulfosuccinate (Aerosol OT). The characteristics of the microemulsions employed as liquid phase have been analysed to interpret the experimental results observed in the absorption process. More specifically, they have been analysed in relation to the percolation phenomenon and the effects produced by this phenomenon upon the different physical properties. Characteristic results have been observed for the gas/liquid mass transfer using microemulsions, because ternary microemulsions with high viscosity values in relation to pure water show a faster absorption process than the carbon dioxide/water system. This characteristic behaviour has been explained on the basis of the microemulsions internal dynamics.     

Preparation of aerogel beryllium borate with supercritical carbon dioxide drying

A supercritical carbon dioxide drying technique was developed to prepare nanometer particulate materials. The technique consists of preparation of an aqueous gel, filtering, washing, replacement of the water in the gel with a mixture solvent of n-butanol and ligroin and supercritical carbon dioxide drying. The product was characterized with TEM, XRD and X-ray small-angle scattering. The results indicated that an amorphous aerogel of the beryllium borate was obtained with this technique. The diameter of the product particles was about 7 nm. Isopropyl alcohol supercritical drying was also used to prepare aerogel beryllium borate, where recrystallization took place due to the high critical temperature of isopropanol.     

超临界二氧化碳介入的α-松油醇催化合成1，8-桉叶素

提出超临界二氧化碳介入α-松油醇异构合成1,8-桉叶素的方法,并采用二极管阵列检测器测量超临界二氧化碳下α-松油醇/环己烷体系的最大吸收波长研究二氧化碳加入量与极性的关系。考察了溶剂体系极性、溶剂量和二氧化碳压力对磷钨酸/聚离子液体（PW/PIL）催化剂催化α-松油醇异构合成1,8-桉叶素的影响,并探讨了超临界二氧化碳介质中,PW/PIL催化剂催化α-松油醇异构合成1,8-桉叶素可能的反应机理。开发了一种绿色高效的1,8-桉叶素合成工艺,当环己烷/α-松油醇的质量比10∶1,PW/PIL催化剂/α-松油醇的摩尔比0.0163∶1,CO₂压力19.0 MPa,50℃反应8 h时,α-松油醇的转化率为89.3%,1,8-桉叶素的选择性为54.6%。研究表明,超临界二氧化碳起到共溶剂、膨胀溶剂、降低溶剂体系极性的三重作用,从而改善了催化剂的团聚现象,提高了1,8-桉叶素的选择性。     

超临界二氧化碳中丙烯酸乙酯/3-氯丙烯接枝天然橡胶的合成与表征

采用超临界二氧化碳溶胀聚合法,以丙烯酸乙酯（EA）/3-氯丙烯（AC）为单体对天然橡胶进行了接枝改性,合成了接枝共聚物NR-g-(EA/AC)。考察了压力和引发剂用量对接枝聚合反应的影响;对NR-g-( EA/AC)进行了红外光谱、力学性能、耐溶剂性、耐燃性、硬度的测试及接枝效率和接枝率的计算,并与溶液聚合法所得NR-g-( EA/AC)的性能进行了比较。结果发现,在接枝橡胶中成功的引入了—C=O和—Cl基团;接枝橡胶的弹性模量、拉伸强度、硬度、耐燃性和耐溶剂性较天然橡胶的有了显著提高。使用溶液法和超临界二氧化碳溶胀聚合法改性天然胶乳都获得了较高的转化率和接枝率,所得产品的机械力学性能相近,但溶液法所得产品的耐溶剂性能优于后一种方法。由于超临界二氧化碳的绿色溶剂性质,超临界二氧化碳溶胀聚合法有望取代溶液聚合法而发展成一种绿色的接枝改性天然橡胶方法。