非离子型表面活性剂的微乳液热力学性质(Ⅱ)——醇类的原子数和活性剂的氧乙烯基团的影响

本文研究了由非离子型表面活性剂、水、甲苯和醇所组成的微乳液,发现醇的烃链上碳原子数直接与热力学函数成线性关系,氧乙烯基团数与自由能、焓以及熵的对数值亦成线性关系。这些结果对研究微乳液的构成和稳定性很有意义。     

超临界二氧化碳微乳液中的表面活性剂

介绍了在超临界二氧化碳(SC-CO_2)下形成微乳液的原理和概念,并且按照所应用各种表面活性剂的结构特点对其在SC-CO_2下形成微乳液的能力分别进行比较和归纳,为今后筛选和设计在SC-CO_2下形成微乳液的表面活性剂提供了重要信息。     

非离子型表面活性剂组成的微乳液热力学性质 (IV) 烷烃的碳原子数影响

由表面活性剂、醇、油和水所组成的微乳液,油相的烷烃长度会影响到微乳液的性质,主要表现在界面相组成和界面张力.Birdi 用加溶法研究以十六烷、硬脂酸钠、水和醇(从C_5到C_9)所组成的微乳液,醇的碳原子数n_a 与标准自由能△G(?)有以下关系:△G(?),醇=1563-839.5n_a(J·mol~(-1)在同样体系内,戊醇和不同烷烃则:     

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.     

助表面活性剂对阴/阳离子表面活性剂复配形成微乳液的影响

中相微乳液;盐度扫描;助表面活性剂对阴/阳离子表面活性剂复配形成微乳液的影响     

非离子型表面活性剂所组成微乳液的异常流变性

以非离子型表面活性剂所组成的微乳液为研究对象,通过测定流变性、粘度、电导和NMR等实验,研究其微观结构.实验表明:在不同水油比范围内有不同结构,在层状结构区也有异常流变性,对此现象有了进一步理解.     

羧甲基纤维素系列高分子表面活性剂形成微乳液的研究

采用紫外光谱、相图、动态激光光散射、同位素示踪、光学显微镜、电导率等研究了羧甲基纤维素系列高分子表面活性剂与甲苯-水-异丙醇体系微乳液的形成过程,发现微乳液粒子大小均一,形态一致,其尺寸比低分子表面活性剂所形成的微乳液粒子大得多.醇分子插入到油水界面,改变了两相界面结构,促使微乳液的生成.电导率测定表明所形成的微乳液区均为水包油结构,即使在富含甲苯区域,亦不会有油包水的反相胶束形成.     

微量热法研究非离子型表面活性剂微乳液

用微量热法研究了由正十六烷／正己醇／水／烷基聚氧乙烯醚组成的微乳液中水的状态，对微乳液中水的模式对热效应的影响进行了解释。在微乳液具有异常流变性的水油比范围内，测定了体系在负触变性状态恢复期间的热效应。     

单一及复合表面活性剂对联苯菊酯微乳液的影响

通过对单一及复合型表面活性剂水溶液临界胶束浓度(CMC)和表面张力(γcmc)的测定分析,研究了表面活性剂对以水为介质、环己酮为溶剂形成的联苯菊酯质量分数为2.5%微乳液相行为及稳定性的影响.结果表明,在几种单一非离子表面活性剂中,苯乙烯基苯酚聚氧乙烯聚氧丙烯醚嵌段型非离子表面活性剂EPE的γcmc最低,为28.18 mN/m;按m(EPE):m(SDBS)=2∶1形成的复合型表面活性剂水溶液的γcmc更低,为27.60 mN/m,有利于O/W型微乳液的形成,当其质量分数为10%时,配制联苯菊酯质量分数为2.5%微乳液的有效成分热贮分解率为2.35%.     

Surface Properties and Etherification in Microemulsion Systems of Novel Brönsted Acid Surfactants

Novel Brönsted acid-surfactants with different alkyl chains were synthesized via a two-step process, and their surface properties were studied. The critical micelle concentration(cmc), surface tension at the cmc(γ_cmc), and ability of these compounds to lower the surface tension by 0.02 N/m(C₂₀ and pC₂₀) were investigated at 25 and 40℃. The molecular architecture of the compounds strongly influenced these physicochemical parameters. The ability of these compounds to lower surface tension was found to be good. Etherification in microemulsions formed by these surfactants as well as dodecylbenzenesulfonic acid(DBSA) was performed; surfactants 3a and 3b were found to be much more efficient than dodecylbenzenesulfonic acid(DBSA).     

Separation of Biphenyl Nitrile Compounds by Microemulsion Electrokinetic Chromatography with Mixed Surfactants

A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 rain. The buffer system contained 100 mmol/L sodium dodecyl sulfate (SDS), 80 mlnol/L sodium cholate (SC), 0.81% heptane, 7.5% n-butanol, 10% acetonitrile and 10 mmol/L borate. The addition of SC, organic modifiers, sample preparation and temperature all showedremarkable effect on the separation. Meanwhile, the MEEKC method was briefly compared with micellar electrokinetic chromatography (MEKC) method.     

Surfactants Synthesis Using Petroleum Fractions and Crude Oil: Application in Microemulsion Formulation

Surfactant synthesis was realized from Algerian crude oil and petroleum fractions. To predict the composition (wt%) in paraffins, naphtenes, and aromatics, the crude oil and petroleum fractions were first characterized using the n-d-PA empirical method of Robert. The characterization showed a good level in aromatics compounds which give high yield in the sulfonation reaction by oleum. The synthesized surfactants were characterized by spectroscopic techniques (UV, FTIR) and by critical micelle concentration (CMC), Krafft temperature, solubility (in aqueous and in salt solution), molecular weight, and matter actives (%) measurements. The formulation of microemulsion using synthesized surfactant from plat format petroleum fraction showed a Winsor III type system. The effect of salinity demonstrates the existence of an optimal value of NaCl concentration for which the interfacial tension takes the lowered value (10^?4 mN/m). Viscosity measurements confirm that the formulated microemulsion has a Newtonian behavior.     

Phase behavior, interfacial composition and thermodynamic properties of mixed surfactant (CTAB and Brij-58) derived w/o microemulsions with 1-butanol and 1-pentanol as cosurfactants and n-heptane and n-decane as oils

Phase diagrams of pseudo-quaternary systems of cetyltrimethylammonium bromide (CTAB)/polyoxyethylene(20)cetyl ether (Brij-58)/water/1-butanol (or 1-pentanol)/n-heptane (or n-decane) at fixed omega (=[water]/[surfactant]) of 55.6 were constructed at different temperatures (293, 303, 313, and 323 K) and different mole fraction compositions of Brij-58 (X(Brij-58)=0, 0.5, and 1.0 in CTAB + Brij-58 mixture). Pure CTAB stabilized systems produced larger single-phase domains than pure Brij-58 stabilized systems. Increasing temperature increased the single-phase domain in the Brij-58 stabilized systems, whereas the domain decreased in the CTAB stabilized systems. For mixed surfactant systems (with X(Brij)=0.5) negligible influence of temperature in the studied range of 293 to 323 K on the phase behavior was observed. Interfacial compositions of the mixed microemulsion systems at different temperature and different compositions were evaluated by the dilution method. The n(a)(i) (number of moles of alcohol at the interface) and n(a)(o) (number of moles of alcohol in the oil phase) determined from dilution experiments were found to decrease and increase respectively for CTAB stabilized systems, whereas an opposite trend was witnessed for Brij-58 stabilized systems. The energetics of transfer of cosurfactants from oil to the interface were found to be exothermic and endothermic for CTAB and Brij-58 stabilized systems, respectively. At equimolar composition of CTAB and Brij-58, the phase diagrams were temperature insensitive, so that the enthalpy of the aforesaid transfer process was zero.     

新型脲基双子表面活性剂的合成及其性能

以N,N-二甲基-1,3-丙二胺、固体光气、溴代烷为原料合成了三种新型含脲基双子表面活性剂(LY-12、LY-14、LY-16),并通过1H NMR、ESI-MS和FT-IR表征了结构。测定了其Krafft点、乳化性能、起泡性能;通过测定表面张力γcmc以及不同温度下的临界胶束浓度(CMC)计算表面活性参数(Γmax、Amin、pc20)与热力学参数(ΔGmθ、ΔHmθ、ΔSmθ)。结果表明,LY-12、LY-14的Krafft点低于0℃,LY-16的Krafft点低于10℃;LY-12、LY-14、LY-16的乳化时间分别为173、275和338 s;LY-12的起泡性显著优于LY-14和LY-16;三种表面活性剂的表面张力γcmc分别为38. 77、37. 42和36. 59 m N/m;298. 15K条件下,其CMC值分别为0. 19、0. 15、0. 13 mmol/L。表面活性参数与热力学参数计算表明,三种表面活性剂均具有高的表面活性且胶束的形成是熵驱动的自发放热过程。     

易水解类表面活性剂的表面与胶团性质

对直链烷基羧酸盐与烷基氯化伯铵两类易水解型表面活性剂进行了较系统的研究,发现pH 值、温度、 盐浓度的变化对体系表面性质及胶团形成有较明显的影响.二类体系中相应水解产物的存在均可较大幅度地提高体系的表面活性,但pH 值在碱性范围内的变化仍对羧酸钠的表面性质与胶团形成有明显影响,而烷基氯化铵的表面性质与聚集能力在酸性条件下则主要受盐浓度的影响,而不受pH 值影响.表明这两类易水解体系产生的极性有机物对各自体系的表面性质和聚集能力影响力度不同.考察了温度对易水解类表面活性剂的影响,并利用相分离模型对相应体系的胶团形成热力学参数进行了计算与讨论.     

以非离子型表面活性剂形成微乳液的碳原子数相关性研究

由非离子型表面活性剂、助表面活性剂（醇）、水和油形成微乳液,用拟三角相图中微乳区的面积确定形成微乳液的最佳条件,实验证明,油的碳原子数加上醇的碳原子数等于表面活性剂的碳原子数对为微乳液形成最佳条件,也符合ＢＳＯ规律。     

稀土气态配合物的热力学性质

稀土气态配合物的热力学性质王林山,王之昌（东北大学化学系,沈阳,１１０００６）关键词稀土气态配合物,热力学性质,钆断目前,对稀土液相和固相配合物已有了较为全面的研究,并总结出其热力学性质与原子序数或离子基态之间有钆断、四分组、斜Ｗ等实验规律或效应［１...