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。     

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.     

2-烷基-1,3-丙二醇β-溴丙醛缩醛的合成及表征

2-烷基-1,3-丙二醇β-溴丙醛缩醛又名5-烷基-2-溴乙基-1,3-二氧六环(3),是合成含1,3-二氧六环的可断裂表面活性剂的中间体[1],这种表面活性剂在中性和碱性条件下很稳定,在酸性条件下易断环变成非表面活性剂,这样可克服在有机合成、分析化学以及研究胶束中的反应等使用普通表面活性剂时因存在令人讨厌的乳浊液而使产物难以分离的缺陷.因此,研究和开发这类表面活性剂,无论在理论上,还是在应用中都具有十分重要的意义.     

2—烷基—1,3—丙二醇β—溴丙醛综醛的合成及表征

2-烷基-1,3-丙二醇β-溴丙醛缩醛又名5-烷基-2-溴乙基-1,3-二氧六环(3),是合成含1,3-二氧六环的可断裂表面活性剂的中间体[1],这种表面活性剂在中性和碱性条件下很稳定,在酸性条件下易断环变成非表面活性剂,这样可克服在有机合成、分析化学以及研究胶束中的反应等使用普通表面活性剂时因存在令人讨厌的乳浊液而使产物难以分离的缺陷.因此,研究和开发这类表面活性剂,无论在理论上,还是在应用中都具有十分重要的意义.     

离子液体表面活性剂1-丁基-3-甲基咪唑烷基硫酸酯的合成及其在水溶液中的聚集行为

采用离子交换法,由1-丁基-3甲基咪唑氯盐（C4mimCl）和烷基硫酸钠合成了一系列无卤素的阴离子表面活性离子液体—1-丁基-3-甲基咪唑烷基硫酸酯[C4mim][CnH2n 1SO4](n=8,12,16),利用表面张力仪、稳态荧光光谱等手段考察了表面活性离子液体在水溶液表面及体相中的聚集行为,结果表明,与传统无机反离子相比,有机咪唑阳离子[C4mim] 作为反离子的离子液体型表面活性剂具有较高的表面活性,[C4mim] 产生的氢键引起的抑制分子规则排列的作用小于其促进分子有序排列的疏水作用。长烷基链的阴离子是界面膜及胶束的主要组成成分,阴离子疏水烷基碳链的增长虽然可促进胶束的形成,但却在一定程度上抑制[C4mim] 离子参与界面或胶束的形成;阴离子所带烷基链越长,越不利于阳离子[C4mim]＋参与界面膜或胶束的形成,界面膜或胶束中表面活性剂排布越松散,即界面张力越大,体系中胶束聚集数较小。     

一种新型表面活性剂的表面活性的研究

采用表面张力法确定了新型表面活性剂3-对壬基苯氧基-2-羟丙基三甲基溴化 铵的临界胶束浓度(cmc)，并考察了盐度、温度和pH值对其cmc的影响。结果表明， 此种表面活性剂的表面活性较高，盐度对其cmc影响最大，其次是pH值，温度对其 cmc的影响较为复杂。理论计算结果表明，采用热力学函数可较好地解释试验结果 。     

油酸酰胺基季铵盐Gemini表面活性剂的制备及性能

以油酸酰胺丙基二甲基胺、1,3-二氯-2-丙醇、1,4-二溴-2-丁烯和1,4-二溴丁烷为原料,分别合成了3种不同连接基团的油酸酰胺基季铵盐阳离子Gemini表面活性剂GS-1、GS-2和GS-3。通过傅里叶变换红外光谱(FT-IR)和核磁共振波谱(1 H NMR)对其结构进行表征,并对其Krafft温度、表面活性、乳化性能、泡沫性能、润湿性等性能进行了测定。结果表明,成功制备了3种Gemini表面活性剂GS-1、GS-2和GS-3,且其Krafft温度均小于0℃,为其低温环境下使用,仍然保持较高表面活性提供了理论可能性。GS-1、GS-2和GS-3的临界胶束浓度(CMC)分别为7.7×10^-5、7.08×10^-5和2.63×10^-6 mol/L,和预期结果一致,Gemini表面活性剂的CMC比传统的单链表面活性剂低1~2个数量级;另外,表面活性剂GS-1、GS-2和GS-3均表现出良好的表面活性、乳化性能和泡沫稳定性。     

(2-己基-1,3-二氧杂戊环-4)甲烷-1-吡啶盐的合成及其表面活性

以脂肪醛、环氧溴丙烷、吡啶为原料,在三氟化硼乙醚的催化下,通过缩合、N-烷基化反应合成了新型含吡啶环1,3-二氧杂环戊烷的单阳离子表面活性剂——(2-己基-1,3-二氧杂戊环-4)甲烷-1-吡啶盐(2),其结构经1H NMR和IR表征.表面活性测试结果表明,2在20℃时临界胶束浓度为4.5×10-3mol·L-1,Krafft点低于20℃,泡沫稳定性72.7％,乳化性2 min.     

系列离子液体型Gemini咪唑表面活性剂在水溶液中的分子动力学模拟

利用分子动力学模拟方法研究了系列离子液体型Gemini咪唑表面活性剂在水溶液中的表面活性和胶束化能力. 模拟结果表明,压力张量法得到的表面张力模拟值偏小,需乘以修正系数矫正;分子动力学模拟得到的临界胶束浓度变化规律与实验相符,可以定性比较不同结构的离子液体型Gemini咪唑分子间的胶束化能力;温度的升高会加剧分子的热运动,不利于离子液体型Gemini咪唑表面活性剂在水溶液中形成胶束;此外,研究还发现联接基不同的离子液体型Gemini咪唑表面活性剂可能遵循不同的胶束化机理.S≤6时,单个分子自组装成胶球后发生聚合形成大胶团.随着咪唑上长烷烃链碳数的增加,[C_n-4-C_nim]胶束化能力提高;而随着联接链长度增加,[C₁₀-S-C₁₀im]胶束化能力降低;当S ＞6时,分子联接基弯曲并伸入其它分子烷烃链内部以减小头基分离力,从而形成稳定的胶束或胶团.随着联接基团亚甲基数的增加,头基斥力减小,附加疏水相互作用增强,[C₁₀-S-C₁₀im]胶束化能力提高.     

全氟辛酸钠与十二烷基三甲基溴化铵混合胶束微环境性质的NMR, ESR研究

应用表面张力法、NMR法和ESR法研究了全氟辛酸钠(SPFO)-十二烷基三甲基溴化铵(DTAB)混合体系水溶液胶束形成及混合胶束的微环境性质(微观粘度、微观极性等).结果表明,碳氟表面活性剂碳氟链和碳氢表面活性剂碳氢链之间具有强烈的相互作用,DTAB与SPFO在水溶液中形成混合胶束.DTAB与SPFO混合体系的表面活性高于单一的DTAB或SPFO,混合体系cmc较单一的DTAB和SPFO低.DTAB与SPFO混合胶束的微观粘度较DTAB胶束的大,而微观极性较DTAB的小.     

Synthesis and properties of ionic liquid-type Gemini imidazolium surfactants

A series of ionic liquid-type Gemini imidazolium surfactants with four-methylene spacer groups were synthesized ([C(n)-4-C(n)im]Br(2), n=10, 12, 14). The surface activity and thermodynamic properties of micellization between the Gemini imidazolium surfactants and their corresponding monomers ([C(n)mim]Br, n=10, 12, 14) were compared by means of surface tension and electrical conductivity measurements. The values of cmc, gamma(cmc), pc(20), Gamma(max), and A(min) derived from surface tension measurement at 25 degrees C suggest that the surface activity of [C(n)-4-C(n)im]Br(2) is higher than that of [C(n)mim]Br. While the thermodynamic parameters of micellization (DeltaG(m)(o), DeltaH(m)(o), DeltaS(m)(o)) derived from electrical conductivity indicate that the micellization of [C(n)-4-C(n)im]Br(2) is entropy-driven, aggregation of [C(n)mim]Br is entropy-driven at low temperature but enthalpy-driven at high temperature. Finally, the activation energy of conductance (E(a)) that is associated with the effective charge is also obtained for [C(n)-4-C(n)im]Br(2) and it is constant below the cmc, but it increases above the cmc.     

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.     

N-酰基-L-丝氨酸钠表面活性剂的合成和胶束化热力学性质

以L-丝氨酸和长链酰氯为原料,合成了3种不同碳链长度（n=8,12,14）的N-酰基-L-丝氨酸。 并以1H NMR、ESI-MS和元素分析对3种目标产物进行了表征。 采用表面张力法研究了N-酰基-L-丝氨酸钠在298、308、318和328 K时水溶液中的聚集行为,确定了临界胶束浓度（cmc）、临界胶束浓度下的最低表面张力（γcmc）、表面饱和吸附量Γmax。 由cmc和温度的关系,应用相分离模型计算了胶束化热力学参数ΔGom、ΔHom和ΔSom。 结果表明,ΔGom＜0,ΔHom的绝对值比-TΔSom绝对值小的多,说明胶束化过程为熵驱动过程,随着温度的升高,胶束化过程是熵-焓补偿的过程。     

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.     

Aggregation behavior of long-chain N-aryl imidazolium bromide in aqueous solution

The aggregation behavior of three long-chain N-aryl imidazolium ionic liquids (ILs), 1-(2,4,6-trimethylphenyl)-3-alkylimidazolium bromide [C(n)pim]Br (n = 10, 12, and 14), in aqueous solutions was systematically explored by surface tension, electrical conductivity, and (1)H NMR. A lower critical micelle concentration (cmc) for the N-aryl imidazolium ILs is observed compared with that for 1,3-dialkylimidazolium ILs [C(n)mim]Br, indicating that the incorporation of the 2,4,6-trimethylphenyl group into a headgroup favors micellization. The enhanced π-π interactions among the adjacent 2,4,6-trimethylphenyl groups weaken the steric hindrance of headgroups and thus lead to a dense arrangement of [C(n)pim]Br molecules at the air-water interface. An analysis of the (1)H NMR spectra revealed that the introduced 2,4,6-trimethylphenyl group may slightly bend into the hydrophobic regions upon micellization. The micelle formation process for [C(n)pim]Br (n = 10, 12, and 14) was found to be enthalpy-driven in the investigated temperature range, which is attributed to the strong electrostatic self-repulsion of the headgroups and the counterions as well as the π-π interactions among headgroups. Strong, stable fluorescence properties are presented by the new N-aryl imidazolium ILs, indicating their potential application in the field of photochemistry.     

Temperature Dependant Micellization of AOT in Aqueous Medium: Effect of the Nature of Counterions

The lithium, potassium, and ammonium salts of bis (2‐ethylhexyl) sulphosuccinic acid have been prepared from the sodium salt (AOT) by applying ion‐exchange technique. The critical micellization concentrations (cmc) of the surfactants with four different counterions have been determined at a temperature range of 10°C to 40°C using surface tension as well as electrical conductivity measurements. Observed data have been utilized to evaluate the ionization degree (counter ion association constant),α, and various thermodynamic parameters of micellization viz, free energy, enthalpy, entropy changes of micelle formation, and also the surface parameters (Γ_max, A_min) in aqueous media. The value of cmc decreases with hydrated ionic size of the counter ions (except K⁺) and follows the order NH₄ ⁺>Na⁺>Li⁺>K⁺. While large negative free energy change (ΔG⁰ _m) and the positive entropy change (ΔS⁰ _m) favor the micellization process thermodynamically, nature of their variation with counterion supports the involvement of counterion size factor in micellization process via a change in the hydrophilicity of surfactant head group.     

Micellization behavior of the ionic liquid lauryl isoquinolinium bromide in aqueous solution

The micellization behavior of the ionic liquid lauryl isoquinolinium bromide ([C₁₂iQuin]Br) in aqueous solution has been assessed using surface tension, electrical conductivity, and ¹H nuclear magnetic resonance (NMR) measurements. The results reveal that the critical micelle concentration (CMC) and constant surfactant tension (γ _cac) are lower than that of butyl isoquinolinium bromide ([C₄iQuin]Br), octyl isoquinolinium bromide ([C₈iQuin]Br, and lauryl pyridinium bromide ([C₁₂Pyr]Br). ¹H NMR spectra show the evidence of paralleled π-stacking of adjacent isoquinoline rings. To elucidate the effect of the π–π interactions on the aggregation process, thermodynamic parameters such as the standard free energy, enthalpy, and entropy of aggregation have been discussed. These parameters are evaluated from the CMC with temperature by fitting these values to expressions derived from a micellization thermodynamic model. The enthalpy–entropy compensation phenomenon has been observed in the micellization process of [C₁₂iQuin]Br in water, and the presence of isoquinoline cations is responsible for the decrease in the ΔH _mic ^? , compared with [C₁₂Pyr]Br which has the same alkyl chain and counter-ion.     

Micelle formation by N-alkyl-N-methylpyrrolidinium bromide in aqueous solution

The micellization of the ionic liquid N-alkyl-N-methylpyrrolidinium bromide (C(n)MPB, n = 12, 14 and 16) in aqueous solutions was investigated by surface tension measurements, electrical conductivity and static luminescence quenching. The effectiveness of the surface tension reduction (Π(cmc)), maximum surface excess concentration (Γ(max)) and the minimum area (A(min)) occupied per surfactant molecule at the air/water interface can be obtained from the surface tension measurements at 25 °C. The critical micelle concentration (cmc) at different temperatures and a series of thermodynamic parameters (ΔG, ΔH and ΔS) of micellization were evaluated from electrical conductivity measurements in the temperature range of 25-45 °C. The thermodynamic parameters show that the micelle formation is entropy-driven at low temperature and enthalpy-driven at high temperature. Furthermore, the micelle aggregation number (N(agg)) of C(n)MPB was calculated according to the Turro-Yekta method through static luminescence quenching and found that N(agg) (49, 55, and 59) increased with the hydrophobic chain length of C(n)MPB.     

Gemini阳离子表面活性剂在水溶液中胶团化行为的温度效 应与焓、熵补偿

测定了Cemini阳离子表面活性剂C~m-----s-----C~m·2Br(m=8,10,12,;s=2,6及m=12;s=3,4)水溶液的电导,从电导(k)～表面活性剂浓度(c)曲线的转折点可求得临界胶团浓度cmc.实验发现,Gemini阳离子表面活性剂的胶团化倾向明显强于其“单体分子”)即单离子头基单烷烃链表面活性剂)。根据质量作用模型计算了胶经过程的吉布氏能、焓和熵的改变。结果表明Gemini表面活性剂聚集机理和其对应的“单体分子”类似,主要来自熵驱动。所有的焓/熵补偿图均呈现良好的线性关系,补偿直线在γ轴的截距随s减小而变小,这意味着具有较小s的Gemini表面活性剂倾向于生成稳定的胶团。     

Synthesis,micellization properties,and cytotoxicity trends of N-hydroxyethyl-3-alkyloxypyridinium surfactants

N-hydroxyethyl-3-alkyloxypyridinium amphiphiles have been synthesized and characterized by various spectroscopic techniques. Self-assembling properties of these amphiphiles have been studied by surface tension, conductivity, and fluorescence measurements. Basic micellization parameters like critical micelle concentration (cmc), surface tension at the cmc (γ _cmc), adsorption efficiency (pC₂₀), effectiveness of surface tension reduction (Π _cmc), maximum surface excess concentration (Γ _max) and minimum surface area/molecule (A _min), and Gibbs free energy of the micellization (ΔG⁰ _mic) have also been determined. The micellization of these 3-alkyloxypyridinium halides in aqueous phase have been found to be exothermic and entropy-driven as assessed by conductivity measurements at different temperatures. Thermal degradation of these surfactants has also been assessed by thermal gravimetric analysis under nitrogen atmosphere. Further, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay of these surfactants on C6 glioma cells show them to be less toxic than conventional cationic surfactants.