醇对W/O型石油醚微乳液性能的影响

以壬基酚聚氧乙烯醚(TX-10)与十六烷基三甲基溴化铵(CTAB)为表面活性剂、石油醚为油相、不同链长的低碳醇(正丙醇、正丁醇、正戊醇、正己醇、正庚醇、正辛醇)为助表面活性剂,配制了一系列微乳液。对微乳液的三元相图进行了研究;通过稀释法测定并计算了不同链长醇由油相迁移至界面相的自由能变化(ΔGθo→i),并对其粒径及表面张力进行了测试;利用Materials Studio7.0(MS)软件验证了不同链长醇对W/O型石油醚微乳液性能的影响。结果表明:制备的微乳液为W/O型;由正辛醇制备的微乳液微乳区域面积最大,ΔGθo→i值最低,为-4.729 8 k J/mol,平均粒径为68.06 nm;微乳液的质量分数为0.5%时,表面张力为24.618 m N/m;CTAB/正辛醇混合体系的χ参数和Emix值分别为10.483 2和6.208 0 k J/mol,TX-10/正辛醇混合体系的χ参数和Emix值分别为11.528 6和6.827 1 k J/mol,说明体系相容性最好,相互作用最强。与其他醇相比,正辛醇是最适宜该体系的助表面活性剂。     

基于相图法的W/O型微乳液体系稳定性分析

以辛基苯基聚氧乙烯醚(TX-10)、十二烷基磺酸钠(SDS)和十六烷基三甲基溴化铵(CTAB)为表面活性剂,以正戊醇、正己醇和正庚醇为助表面活性剂,以正戊烷为油相,制备了油包水型(W/O)微乳液.用相图法分析了微乳液体系的热力学稳定性,计算了水核半径的大小,并考察了影响微乳液W/O区域范围的各种因素.结果表明:这几种微乳液体系在实验条件下能自发形成:微乳液的水核半径处于纳米量级,可作为制备纳米粒子的超微反应器;以TX-10为表面活性剂时,水核可以包容更多的水分子,微乳液的W/O区域较大;而以CTAB为表面活性剂时,由于其极性头之间的空间和静电排斥作用强,微乳液的W/O区域最小;以硝酸镧溶液作为分散相时,微乳液的W/O区域变化较小;随着温度的升高,微乳液的W/O区域显著减小.     

异辛基酚聚氧乙烯醚/十二烷基溴化吡啶混合溶液的表面性质及各组分含量的测定

对不同组成的异辛基酚聚氧乙烯醚(TX-100)和十二烷基溴化吡啶(DDPB)混合表面活性剂在KH2PO4/Na2HPO4缓冲溶液中的表面性质进行了研究,结果表明TX-100和DDPB间存在着较弱的作用。研究结果证实利用高效毛细管电泳法能够较准确地测定该混合体系中各单组分表面活性剂的含量;并能将该方法用于测定TX-100和DDPB的临界胶束浓度。     

二元表面活性剂体系微乳液的相行为及热力学研究

用表面张力法研究了苯乙烯基酚聚氧乙烯聚氧丙烯醚嵌段型非离子表面活性剂(PEP)分别与十二烷基硫酸钠(SDS)、十二烷基三甲基溴化铵(CTAB)复配体系分子间的相互作用,并根据测定的临界胶束浓度(CMC)及正规溶液理论计算了复配体系分子间相互作用参数及分子交换能,考察了表面活性剂、助表面活性剂、温度等因素对复配表面活性剂体系微乳液形成过程的相行为及热力学性质的影响。结果表明,二元组分(PEP+SDS)及(PEP+CTAB)复配体系在胶束中和表面吸附层中的都存在较强的增效作用,体系的能量降低,且前者的增效作用大于后者。(PEP+SDS)/正己醇/正庚烷/水微乳液的W/O微乳区域面积最大,温度对该微乳液的相行为影响很小。在此微乳液形成的过程中,助表面活性剂醇从连续油相进入微乳液界面层的标准自由能变化ΔGs0;标准焓变-ΔHs=0,为无热效应过程,ΔGs是由醇分子的混乱度熵变ΔSs决定的。     

新型表面活性剂疏水缔合聚合物提高原油采收率的性能研究

介绍了渤海海上油田二元复合驱驱油的设计与开发方案,以新型表面活性剂(非离子型表面活性剂:DMES-14、TX-100)和疏水缔合聚丙烯酰胺(HAPAM)为主。二元复合驱驱油体系主要需要双子表面活性剂双十四酸乙二酯双磺酸盐型表面活性剂(DMES-14),疏水缔合聚丙烯酰胺以及取自海上油田平台的回注水。该体系同时对粘度和表面张力进行了研究。结果表明,该体系在不要求浓度的情况下可以达到超低界面张力2.48×10~(-3) m N/m,在油藏中粘度可达到55 m Pa;随后的岩心驱替试验表明,在水驱含水75%的状况下进行二元复合驱驱油效果可提高至38.6%以上。总之,该实验研究提供了非离子表面活性剂与疏水缔合水溶性聚合物驱油体系的实用信息以及可以在渤海海上油田进行大规模应用HAPAM。     

连接基长度对GSS/TX-100复配体系表面性质的影响

研究了不同连接基的琥珀酸酯磺酸盐型双子表面活性剂(GSS)与辛基苯基聚氧乙烯醚(TX-100)复配体系(GSS/TX-100)在水溶液中的表面性质和胶团化行为,对混合胶团和表面吸附层的组成和相互作用参数进行了计算。结果发现:复配体系水溶液在形成胶团和表面吸附时无明显甚至不存在正加和增效,但是TX-100的加入可明显降低GSS的临界胶束浓度,混合胶团中TX-100占胶团的主要成分,GSS与TX-100具有较弱的相互作用,连接基较短的GSS更易形成胶束,也更易与TX-100形成混合胶束。     

α-烯基磺酸钠和十六烷基三甲基溴化铵复配体系的泡沫性能

利用Ross-Miles法、电导率法和光学法等研究了阴离子表面活性剂α-烯基磺酸钠(AOS)和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)不同摩尔比复配溶液的泡沫性能。结果表明,在表面活性剂的总浓度为cT=7.8×10-3mol/L时,AOS/CTAB不同摩尔比复配溶液的发泡性能与AOS溶液基本相当,但AOS/CTAB复配能较明显地提高体系的泡沫稳定性;不同摩尔比复配溶液的泡沫稳定性顺序为:AOS/CTAB 5∶1>AOS/CTAB 10∶1>AOS/CTAB15∶1>AOS/CTAB 20∶1>AOS。     

柴油微乳化技术研究

考察了不同种类的醇、阳离子表面活性剂与非离子表面活性剂以及非离子表面活性剂与非离子表面活性剂不同配比对形成柴油微乳液水增溶量的影响。结果表明：正戊醇为最佳助剂，碳链太长、太短或带支链均不易于形成微乳液；复配体系D0821／AEO3要比D1221／AEO3增溶效果好，与TX-4／AEO3和D0821／TX-4／AEO3体系进行对比，确定D0821／TX-4／AEO3为最佳复配体系，不仅增溶的水量多，成本也大大减少。在m(D0821)：m(TX-4)：m(AEO3)为15：14：21时，最大增溶水的质量分数将近29％，总表面活性剂质量分数6％多，正戊醇质量分数3％多。     

TX-100反相微乳液体系稳定性的研究

以最大增容水量为考察目标,研究了温度、HLB值和助表面活性剂含量对TX-100/正己醇/环己烷反相微乳液体系稳定性的影响,绘制了该反相微乳体系的拟三元相图,并用电导率法讨论了微乳液的微观结构。结果表明,当温度t=25℃,TX-100与正己醇质量比为1.5时,体系具有最大的增容水量;在不同的增容水量时体系存在3种不同的微乳区域,即油包水、水包油和油水双连续区域。     

GSS362/TX-100复配体系在水中的溶液行为研究

研究了1,3-丙二醇双子琥珀酸二异辛酯磺酸钠(GSS362)和辛基酚聚氧乙烯醚(TX-100)复配物在水中的表面性质和胶束化行为,并对理想混合临界胶束浓度以及混合体系中各组分在表面吸附层和胶束中的组成、相互作用参数和热力学参数进行分析计算。结果表明,复配物在水溶液中不存在协同效应,但是TX-100的加入明显降低了GSS362的临界胶束浓度,混合胶束的形成为自发过程,胶束中GSS362与TX-100分子具有较弱的相互作用,胶束中富含非离子表面活性剂TX-100。     

阴/阳离子表面活性剂复配微乳液体系的ε-β“鱼状”相图研究

用ε-β“鱼状”相图法研究了离子液体表面活性剂溴化1-十二烷基-3-甲基咪唑（C12mimBr）与十二烷基硫酸钠（SDS）复配形成的SDS-C12mimBr/正丁醇/正辛烷/5%NaCl水溶液微乳液体系的相行为和增溶性能。阴、阳离子表面活性剂以不等摩尔比复配,由于强烈的静电作用,产生显著的协同作用,使复配体系的增溶性能比单一表面活性剂得到了显著的提高。     

Synergism and Performance for Systems Containing Binary Mixtures of Anionic/Cationic Surfactants for Enhanced Oil Recovery

The surfactant structure–performance relationship and application properties in enhanced oil recovery (EOR) for binary mixtures of anionic and cationic surfactants are presented and discussed. A polyoxyethylene ether carboxylate anionic surfactant was blended with a quaternary ammonium chloride cationic surfactant and tested for a high-temperature, low-salinity, and high-hardness condition as found in an oil reservoir. These mixtures were tailored by phase behavior tests to form optimal microemulsions with normal octane (n-C8) and crude oil having an API gravity of 48.05°. The ethoxy number of the polyoxyethylene carboxylate anionic surfactant and the chain length of the cationic surfactant were tuned to find an optimal surfactant blend. Interfacial tensions with n-C8 and with crude oil were measured. Synergism between anionic and cationic surfactants was indicated by surface tension measurement, CMC determination, calculation of surface excess concentrations and area per molecule of individual surfactants and their mixtures. Molecular interactions of anionic and cationic surfactants in mixed monolayers and aggregates were calculated by using regular solution theory to find molecular interaction parameters β ^σ and β ^M . Morphologies of surfactant solutions were studied by cryogenic TEM. The use of binary mixtures of anionic/cationic surfactants significantly broadens the scope of application for conventional chemical EOR methods.     

含离子液体的复配表面活性剂微乳液的电导性质

研究了CTAB和TritionX-100复配表面活性剂在氯仿作为溶剂时,增溶离子液体bmimBF(IL)时所形成非水微乳液的电导性质,并且与含水体系的微乳液作了比较,发现两者存在较大的差别.在非水微乳液中,随着离子液体质量分数的增加,体系经历了IL/O型微乳液、双连续相、O/IL微乳液三种状态,并且采用循环伏安法对此结论进行了验证.两种表面活性剂复配后,在IL/O型微乳液阶段电导率随着CTAB的摩尔分数(α)增大而增大,在双连续相和O/IL微乳液阶段,体系的电导率随着α增大而减小.在含水微乳液中,只出现O/W型微乳液,而且随着增溶水质量分数的增加电导率下降.增溶水量一定的情况下,电导率随着α值增大而增大.     

无机盐对十六烷基三甲基溴化铵（CTAB）微乳液相行为的影响

微乳液通常由水、油、盐、表面活性剂及助剂组成,各组分对微乳液体系的相行为及增溶情况都有影响。本文利用Winsor相图和ε-β鱼状相图来研究无机盐种类、浓度对十六烷基三甲基溴化铵（CTAB）型微乳液相行为的影响。研究发现,随着无机盐浓度或醇量增加,微乳液都会发生从WinsorⅠ→WinsorⅢ→WinsorⅡ的相转变,但具有不同阳离子或阴离子的无机盐对微乳液体系相行为的影响不同。无机盐在微乳液体系中主要与表面活性剂的反离子发生作用,对阳离子表面活性剂配成的微乳液体系,无机盐阴离子的作用比较强,且价态越高,离子半径越大,对微乳液相态的影响越大。通过对不同无机盐条件下的界面组成及增溶参数分析可知：无机盐种类的改变对鱼头、鱼尾点表面活性剂含量及醇在界面层中的分布影响较小;无机盐中阴离子改变对微乳液增溶能力影响较大,阳离子的改变对微乳液增溶能力影响较小。     

Selective nitration of phenol to ortho-nitrophenol using dilute nitric acid by microemulsion of cetytrimethylammonium bromide (CTAB) in isooctane

The paper reports near-selective nitration of phenol to ortho-nitrophenol using CTAB microemulsion solution in the presence of dilute nitric acid. The difference betweem the selective nitration of different kinds of surfactants such as AOT (anionic surfactant) and CTAB (cationic surfactant) has been investigated. All these experimental results indicate that microemulsions can be selective to give the ortho-phenol.     

Environmentally Friendly Vegetable Oil Microemulsions Using Extended Surfactants and Linkers

Microemulsion formation of triglyceride oils at ambient conditions (temperature and pressure) and without the addition of co-oil and/or alcohols is challenging at best. Undesirable phases, such as macroemulsions, liquid crystals and sponge phases, are often encountered when formulating triglyceride microemulsions. The purpose of this study is to investigate the use of extended surfactants, lipophilic linkers, and hydrophilic linkers in enhancing triglyceride solubilization and interfacial tension reduction. We have studied two classes of extended surfactants, linear alkyl polypropoxylated sulfate (LAPS) surfactants and linear alkyl polypropoxylated ethoxylated sulfate (LAPES) surfactants. Linkers evaluated were oleyl alcohol (lipophilic linker), sodium mono and dimethyl naphthalene sulfonate (SMDNS), and polyglucoside (hydrophilic linkers). Oils studied include olive, peanut, soybean, canola and sunflower oils. The effect of electrolyte concentration on microemulsion phase behavior was studied. The microemulsion “fish” diagram was obtained by plotting the total surfactant and linker concentrations versus the electrolyte concentration. We were able to form Winsor Type I, II, III and IV microemulsions at ambient conditions and without co-oil or short and medium chain length alcohol addition. Winsor Type III and IV triglyceride microemulsions are particularly useful in numerous applications such as cosmetics, vegetable oil extraction and soil remediation.

Formulating middle-phase microemulsions using mixed anionic and cationic surfactant systems

Although mixtures of anionic and cationic surfactants can show great synergism, their potential to precipitate and form liquid crystals has limited their use. Previous studies have shown that alcohol addition can prevent liquid crystal formation, thereby allowing formation of middle-phase microemulsions with mixed anionic-cationic systems. This research investigates the role of surfactant selection in designing alcohol-free anionic-cationic microemulsions. Microemulsion phase behavior was studied for three anionic-cationic surfactant systems and three oils of widely varying hydrophobicity [trichloroethylene (TCE), hexane, and n-hexadecane]. Consistent with our hypothesis, using a branched surfactant and surfactants with varying tail length allowed us to form alcohol-free middle-phase microemulsion using mixed anionic-cationic systems (i.e., liquid crystals did not form). The anionic to cationic molar ratio required to form middle-phase microemulsions approached 1∶1 for univalent surfactants as oil hydrophobicity increased (i.e., TCE to hexane to n-hexadecane); even for these equimolar systems, liquid crystal formation was avoided. To test the use of these anionic-cationic surfactant mixtures in surfactant-enhanced subsurface remediation, we performed soil column studies: Greater than 95% of the oil was extracted in 2.5 pore volumes using an anionic-rich surfactant system. By contrast, cationic-rich systems performed very poorly (<1% oil removal), reflecting significant losses of the cationic-rich surfactant system in the porous media. The results thus suggest that, when properly designed, anionic-rich mixtures of anionic and cationic surfactants can be efficient for environmental remediation. By corollary, other industrial applications and consumer products should also find these mixtures advantageous.     

表面活性剂对聚乙烯醇基薄膜透光性及机理的影响

针对聚乙烯醇（PVA）与表面活性剂能组成复配体系,制备了聚乙烯醇基亲水性薄膜材料,研究了表面活性剂的掺量对聚乙烯醇基薄膜的微观结构、孔隙度、透光性能、PVA结晶度及晶粒尺寸的影响。采用紫外分光光度计考察了各薄膜的透光性;采用扫描电子显微镜观察了聚乙烯醇/表面活性剂的横截面微观结构;采用X射线衍射仪考察了不同表面活性剂的添加量对复合薄膜的晶相组成及PVA晶粒尺寸的影响,结果表明当表面活性剂添加量在6%~10%（质量分数,下同）时,阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）明显地降低聚乙烯醇的结晶度,而阴离子表面活性剂十二烷基苯磺酸钠（SDBS）则没有此效果;CTAB的加入使聚乙烯醇/CTAB体系中PVA晶粒尺寸增大,SDBS的加入使聚乙烯醇/SDBS体系中PVA晶粒尺寸减小。最后对聚乙烯醇与表面活性剂相互作用机理示意图进行了预测。     

Wettability reversal of reservoir rock surface through surfactant stabilized microemulsion

In the process of the tertiary recovery of oil and gas resources, it is necessary to use external fluids to displace the crude oil in the reservoir. Whether the crude oil on the surface of the rock can be effectively displaced and the wettability of the rock can be changed to avoid re-adsorption by the crude oil is directly related to the level of oil recovery. Therefore, it is critical to study the cleaning and wettability reversal of reservoir rock surface. Because microemulsions have outstanding performance in changing the wettability of rocks and solubilizing crude oil, this paper uses cetyl trimethyl ammonium bromide (CTAB) as a surfactant and n-butanol as a co-surfactant to prepare microemulsions. The performance of microemulsions with different microstructures on the cleaning and wettability changes of crude oil on the rock surface were studied. The results show that the water-in-oil (W/O) microemulsion has good cleaning efficiency, and the oil removal rate on the sandstone core surface can reach 79.65%. In terms of changing the wettability of the rock surface, W/O, bi-continuous phase (B.C.) and oil-in-water (O/W) microemulsions can change the core surface from lipophilic to hydrophilic. And the effects of the B.C. and O/W microemulsions are more obvious. The microemulsion system that was prepared based on cationic surfactants has a good application prospect in changing the wettability of the reservoir and cleaning the adsorbed crude oil.     

Microemulsion formation and detergency with oily soils: I. Phase behavior and interfacial tension

The ultimate objective of the project was to investigate the relationship between microemulsion phase behavior and detergency for oily soils. In this study, surfactant phase behavior was evaluated for hexadecane and motor oil as model oily soils. Producing microemulsions with these oils is particularly challenging because of their large hydrophobic character. To produce the desired phase behavior we included three surfactants with a wide range of hydrophilic/lipophilic character: alkyl diphenyl oxide disulfonate (highly hydrophilic), dioctyl sodium sulfosuccinate (intermediate character), and sorbitan monooleate (highly hydrophobic). This mixed surfactant was able to bridge the hydrophilic/lipophilic gap between the water and the oil phases, producing microemulsions with substantial solubilization and ultralow interfacial tension. The effects of surfactant composition, temperature, and salinity on system performance were investigated. The transition of microemulsion phases could be observed for both systems with hexadecane and motor oil. In addition, the use of surfactant mixtures containing both anionic and nonionic surfactants leads to systems that are robust with respect to temperature compared to single-surfactant systems. Under conditions corresponding to “supersolubilization”, the solubilization parameters and oil/microemulsion interfacial tensions are not substantially worse than at optimal condition for a middle-phase system, so a middle-phase microemulsion is not necessary to attain quite low interfacial tensions. A potential drawback of the formulations developed here is the fairly high salinity (e.g., 5 wt% NaCl) needed to attain optimal middle-phase systems. The correlation between interfacial tension and solubilization follows the trend predicted by the Chun-Huh equation.