酰胺基团对Gemini表面活性剂表面活性和聚集行为的影响

本文合成了含酰胺基团和不含酰胺基团的两类Gemini阳离子表面活性剂,测定了其表面活性参数,研究了酰胺基团对表面活性剂的表面活性和聚集行为的影响。结果表明,酰胺基团提高了Gemini阳离子表面活性剂的临界胶团浓度,降低了胶团聚集数,增强了胶团微极性,增大了表面活性剂的饱和吸附量。     

Gemini阳离子表面活性剂的合成及其胶束生成 Gemini阳离子表面活性剂的合成及其胶束生成

Cationic Gemini surfactants, alkanediyl-α,ω-bis(dimethyldodecylammonium bromide) have been synthesized by the following method: firstly dodecyl bromide was prepared by the reaction of dodecanol with bromic acid in the presence of strong sulfuric acid. Dodecylbromide was then reacted with N,N-tetramethyl ethane diamine(or N,N-tetramethyl hexana diamine) to prepare the title-compounds. Micellization of these Gemini surfactants was investigated using conductivity measurement. The results showed that the critical micelle concentration(cmc) of the Gemini surfactants has a much lower value compared with that of the corresponding “ monomer” . For a series of the Geminis with the same length(s) in the spacer chain, the cmc decreased with increasing the carbon number (m) in the alkyl chain. The aggregation number(N) of the micelle also drastically decreased with m. For the same value of m, the cmc varied slightly with s, which indicated that the electrostatic interaction between the ionic-groups of the “ monomer” has been naturally changed duo to a link between the two ionic-groups of the “ monomer” through a spacer. However, N was strongly decreased with s,which may be a reason of steric inhibition coming from the ionic-groups due to a link of spacer. With increasing temperature, micellization of the Gemini surfactants was slightly enhanced.     

Gemini阳离子表面活性剂的合成及其胶束生成

传统的单头基单烷烃链表面活性剂由于离子头基间的电荷斥力或水化引起的分离倾向使得它们在界面或分子聚集体中难以紧密排列,造成表面活性偏低 .为克服这一缺陷进行了大量尝试,例如添加无机电解质屏蔽离子头基的电荷斥力、升高温度以降低头基的水化,甚至采用合适的二元表面活性剂复配等等 .当前一种从根本上克服头基间分离倾向的化学方法正受到关注 [1],这种方法通过化学键将二个单头基单烷烃链表面活性剂在离子头基处用联接基团（ spacer）使其联接起来,从而获得称之为 Gemini的新型表面活性剂 [2]. Gemini表面活性剂大大促进了其 "…     

新型不对称季铵盐Gemini表面活性剂的合成及其表面活性

以溴代烷和N,N,N′,N′-四甲基乙二胺为原料,经过两步季铵化反应合成了一种新型的不对称型阳离子Gemini表面活性剂——二亚甲基-1-正己基二甲基溴化铵-2-十八烷基二甲基溴化铵(3),其结构经1H NMR和元素分析表征.研究结果表明,3的Krafft点为21.9℃,且聚集能力强.     

醇对非离子型表面活性剂浊点的影响

研究了醇对非离子型表面活性剂浊点的影响，发现直链醇的碳原子数小于４时随着其在表面活性剂中含量的增加浊点上升；当碳原子数大于４时，则随着醇含量的增加浊点下降。醇的构型对浊点起着重要作用。     

尾链含对硝基苯醚基团的阳离子Gemini表面活性剂的胶束化热力学

利用等温滴定微量量热法和电导法研究了具有不同疏水链长并且疏水链尾部含有对硝基苯醚基团的Gemini表面活性剂胶束化过程的热力学, 分别利用相分离模型和质量作用模型对观察焓与浓度的关系曲线进行拟合, 获得了胶束化过程的热力学参数. 两种模型获得的胶束化焓一致, 均为较大负值, 而吉布斯自由能却相差较大. 用相分离模型得到的胶束化过程的热容变化均为负值, 并随链长增加绝对值增大, 胶束化过程总的热容变化主要来自非极性的烷基链去水合产生的热容变化, 证明处于疏水链末端的对硝基苯醚基团在表面活性剂形成胶束后依然与水相接触. 质量作用模型获得的胶束聚集数随疏水链长增加逐渐下降, 这是由具有长疏水链的表面活性剂形成预胶束所导致.     

支链化阳离子和甜菜碱表面活性剂对聚四氟乙烯表面润湿性的影响

利用座滴法研究了支链化阳离子表面活性剂十六烷基羟丙基氯化铵(C₁₆GPC)和两性离子表面活性剂十六烷基羧酸甜菜碱(C₁₆GPB)在聚四氟乙烯(PTFE)表面上的吸附机制和润湿性质, 考察了表面活性剂浓度对表面张力、接触角、粘附张力、固液界面张力和粘附功的影响趋势. 研究发现, 低浓度条件下, 表面活性剂疏水支链的多个亚甲基基团与PTFE表面发生相互作用, 分子以平躺的方式吸附到固体界面; 支链化表面活性剂形成胶束的阻碍较大, 浓度大于临界胶束浓度(cmc)时, C₁₆GPC和C₁₆GPB分子在固液界面上继续吸附, 与PTFE作用的亚甲基基团减少, 分子逐渐直立, 固液界面自由能(γ_sl)明显降低. 对于支链化的阳离子和甜菜碱分子, 接触角均在浓度高于cmc后大幅度降低.     

琥珀酸酯磺酸盐Gemini表面活性剂的合成及表面活性

以1-十二醇、1-十四醇、1-十六醇、1-十八醇、马来酸酐和乙二醇为主要原料,合成4种琥珀酸酯磺酸盐Gemini表面活性剂;借助红外光谱和核磁共振氢谱对所合成的化合物结构进行了表征。 4种表面活性剂均具有较低的临界胶束浓度,较强的乳化性能以及较好的泡沫性能。 进一步讨论了4种表面活性剂结构与性能的关系。     

季铵盐型Gemini表面活性剂的胶束化动力学研究

采用停流法并结合Aniannson-Wall理论, 研究了联接基为(CH2)2, (CH2)3, (CH2)4和(CH2)6的季铵盐型Gemini表面活性剂胶束的形成-破坏过程. 动力学的研究结果表明, 胶束形成-破坏过程的弛豫时间(τ2)与联接基的长度、表面活性剂的浓度、反离子的浓度以及温度有关. 随联接基长度的增加, 季铵盐型Gemini表面活性剂胶束形成-破坏过程的弛豫时间缩短. 当温度高于293 K时, 随着反离子浓度的增加, 1/τ2将出现一个最低值. 根据核化焓结果提出了不同的联接基长度的季铵盐型Gemini表面活性剂具有不同的胶束形成-破坏过程的机理.     

NaCl对烷基苯磺酸盐Gemini表面活性剂水溶液性质的影响

采用旋滴法测定了烷基苯磺酸盐Gemini表面活性剂Ia水溶液与正庚烷的界面张力,用超微电极循环伏安法测定了水溶液中Ia的胶束扩散系数.结果发现,NaCl的加入能够使界面张力降低2倍左右,使Ia的胶束扩散系数变大;Ia浓度增大,胶束扩散系数变小,而NaCl浓度增大,胶束扩散系数变大.这些变化说明NaCI的加入使得Ia胶束大小发生了变化.这是由于NaCl的加入降低了Ia离子头基之间的静电斥力,使得Ia分子排列更加紧密,更有效降低了油水的界面张力,使胶束形状变小;同时胶束表面电荷得到中和,胶束的静电斥力相应减小,胶束流动性相应增加,从而表现出较大的胶柬扩散系数.     

季铵盐阳离子型双子表面活性剂的合成及其表面活性

以二甲基长链烷基叔胺和1,5-二溴戊烷为起始原料合成了系列不同疏水烷基长度的阳离子型双子表面活性剂m-5-m(m=8, 12, 16).对其表面活性进行了初步研究,结果表明:所合成的系列产物都具有较好的表面活性,其中16-5-16具有最低的临界胶束浓度(CMC 0.289 mmol·L-1);随着疏水烷基链的增长,表面活性剂的CMC显著降低.对应的表面张力(γCMC)则随m的增加先降低,后增高,当疏水链为12个碳时为最低值;8-5-8的表面活性最差.     

阴离子孪连表面活性剂的合成及其表/界面活性研究

合成了疏水链长度不同和连接基长度不同的7种系列阴离子孪连表面活性剂,研究了它们的表/界面活性。结果表明,它们有较低的表面张力和临界胶束浓度(CMC),有很好的表面活性。它们的CMC都在10-5~10-6mol/L之间,表面张力在26·5~34mN/m之间。它们有非常好的抗一价、二价盐的能力。除了C16-C2-C16在高于5%的NaCl溶液中会产生析出外,其余孪连表面活性剂都能耐盐20%以上。随着盐浓度的增加,孪连表面活性剂与烷烃间的界面张力逐渐降低,能达到10-3mN/m。与中原油田原油间的界面张力能降低到10-3~10-4mN/m,表明它们可应用于特高矿化度油藏提高采收率。     

Novel Cationic Gemini Surfactants Based on Piperazine: Synthesis,Surface Activity,and Foam Ability

A series of novel Gemini surfactants C_n-pi-C_n with piperazine moiety as spacer was synthesized and characterized by IR, ¹H NMR, and mass spectra. Their surface activities were evaluated by surface tension, electrical conductivity, and steady-state fluorescence. The obtained results indicated that the synthesized Gemini surfactants exhibited lower critical micelle concentration (cmc) and surface tension (γ_cmc) compared with traditional surfactants. The steady-state fluorescence measurement and electrical conductivity were recorded to demonstrate the accuracy of cmc values. In addition, the micellization was evaluated using conductivity measurement in the temperature range of 298–308 K. The foamability and foam stability of these Gemini surfactants were also examined. In which, the Gemini surfactant with the shortest chain (C₁₂) showed the best foamability but the poorest foam stability. Hydrophile–lipophile balance and emulsifying ability were studied and a comparatively poor emulsifying ability displayed.     

Synthesis and Surface Activity of Novel Triazole—based Cationic Gemini Surfactants

Gemini surfactants, which contain two hydrophilic groups and two hydrophobic groups in the molecule, are considered as a new generation of surfactants. These surfactants are about 3 orders of magnitude more efficient at reducing surface tension and more than 2 orders of magnitude more efficient at forming micelles than conventional surfactants1. During recent years, many gemini surfactants have been synthesized, and a considerable number of investigations have been reported on their unusua…     

Synthesis and Surface Properties of Novel N-Alkyl Quinoline-Based Cationic Gemini Surfactants

Two series of cationic dimeric (gemini) surfactants are prepared with respect to key surfactants properties, such as surface activity and solubilization. The influence of both the dimerization and the spacer group is examined in order to establish structure-property relationships. The surface tension and critical micelle concentration can be markedly reduced compared to the monomeric surfactants in the pure state. The critical micelle concentration (cmc) of each series has been determined using equilibrium surface tension measurements. Furthermore, air/water interface parameters including effectiveness (π_cmc), efficiency (P_C20), maximum surface excess (Γ _max ), and minimum surface area (A _min ) have been also derived using Gibb's adsorption equation at 25°C. Standard free energies of micellization and adsorption were calculated. Solubilization behaviors of the synthesized surfactants were measured towards paraffin oil as solubilized material using light transmission technique.     

手性赖氨酸基Gemini表面活性剂的表面性能

用表面张力法、电导法和稳态荧光法研究了手性Gemini表面活性剂[C₁₂-m-C₁₂] Na₂（m=2,4,6）和[C₁₂-T-C₁₂] Na₂的表面性能及临界胶束聚集数,并计算胶束形成的热力学参数,用圆二色谱法考察了[C₁₂-2-C₁₂] Na₂在不同浓度下的立体构型. 结果表明,手性Gemini表面活性剂的临界胶束浓度（cmc）和临界表面张力γ_cmc随着连接基链长增加或刚性增强而增大;ΔG_m⁰和ΔH_m⁰为负值,|ΔH_m⁰|比|-TΔS_m⁰|小很多,说明胶束化过程为熵驱动的自发放热过程;随着连接基链长增加或刚性增强,ΔG_m⁰和ΔH_m⁰逐渐增大,ΔS_m⁰和临界胶束聚集数逐渐减小,表明其胶束化能力随之降低;当浓度大于cmc时,手性Gemini表面活性剂可形成手性超分子聚集体.     

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。     

基于胱氨酸的Gemini型表面活性剂的合成及其性质

合成了基于胱氨酸的两种Gemini表面活性剂, N,N’-二对丁氧基肉桂酰胺基胱氨酸钠(SDBCC)和N,N’-二癸酰胺基胱氨酸钠(SDDC). 利用表面张力、动态光散射(DLS)、透射电镜(TEM)等手段研究了体系的表面性质和聚集行为.     

Synthesis and Evaluation of Surface Activity of Gemini Borate Surfactants Based on Glucose Moiety

A series of Gemini borate surfactants were synthesized based on glucose molecule. Their chemical structures were confirmed using ¹H-NMR,¹³C nuclear magnetic resonance (NMR), and mass spectroscopy. The surface activities of these Gemini amphiphiles were measured, including surface tension (γ), critical micelle concentration (CMC), effectiveness (II_cmc), efficiency (pC₂₀), maximum surface excess (Γ_max), and minimum surface area (A_min) at different temperatures 25, 35, and 45°C either in pure water or in water–ethanol mixture (10%). Also, thermodynamic data including free energy, entropy, and enthalpy changes (ΔS, TΔS, ΔH) for adsorption at the air–water interface and also for micellization in surfactant solutions were calculated.