6种燕尾形苝二酰亚胺类双子表面活性剂对碱性锌电极缓蚀机理理论研究

为了研究燕尾型苝二酰亚胺类双子表面活性剂对碱性锌电极缓蚀机理,利用密度泛函理论（DFT）和分子动力学模拟（MD）方法,探讨了两类共6种燕尾型苝二酰亚胺类双子表面活性剂的吸附行为。DFT计算结果表明,前线分子轨道分布主要位于分子核心的苝二酰亚胺骨架上,且苝二酰亚胺骨架上的N原子为分子的反应活性中心。分子动力学模拟表明,6种燕尾型苝二酰亚胺类双子表面活性剂均能与水溶液中的金属锌表面发生相互作用,N₂、P₂在两类双子表面活性剂中均表现出有较高的吸附能和较大的扩散系数,吸附能分别为-11315.868 kcal/mol、-10785.698 kcal/mol,扩散系数分别为2.5、1.32;研究结果同时表明,N₂和P₂形成的双子表面活剂膜层对腐蚀粒子OH^-的阻止效果较好,能够在金属锌表面起到很好的缓蚀效果。     

阴离子双子表面活性剂分子结构对其溶液黏度的影响

用流变仪考察了分子结构对阴离子双子表面活性剂溶液黏度的影响,并用SEM观察了其溶液微观结构变化,探讨了其对溶液黏度影响的机理。结果表明:间隔基团碳数(s)=2,疏水链碳数(m)=12或14时,亲水头基类型对其双子表面活性剂溶液黏度影响呈现相同规律,即羧酸盐磺酸盐硫酸酯盐;当s=2时,疏水链碳数增加,羧酸盐双子表面活性剂溶液黏度增大,磺酸盐双子表面活性剂溶液黏度呈波动上升;疏水链碳数相同,间隔基团碳数增加,磺酸盐双子表面活性剂溶液黏度先增大后减小,羧酸盐双子表面活性剂溶液黏度减小,其中,DS18-3-18和DC16-2-16增黏效果好;温度升高,DS18-3-18和DC16-2-16溶液黏度下降,但90℃时DS18-3-18溶液黏度大于DC16-2-16。微观结构表明:间隔基团碳数增大,DS18-s-18溶液胶束结构由球状变为片状直至球状,导致溶液黏度先增后降。温度升高,DS18-3-18溶液中片状胶束数目呈下降趋势,至90℃时,溶液中仍有联结完好的片状胶束存在,因此,DS18-3-18具有较好的耐温增黏性。     

阴离子双子表面活性剂分子结构对其溶液黏度影响及机理

为优选耐高温清洁压裂液增黏剂,用流变仪考察了分子结构、温度变化对阴离子双子表面活性剂溶液黏度的影响,并用扫描电镜研究了其溶液微观结构变化,探讨了其对溶液黏度的影响机理。结果表明,间隔基团碳数s=2,疏水链碳数m=12或14时,亲水头基类型对其双子表面活性剂溶液黏度影响呈现相同规律（羧酸盐>磺酸盐>硫酸酯盐）;间隔基团碳数s=2时,疏水链碳数增加,羧酸盐双子表面活性剂溶液黏度增大,磺酸盐双子表面活性剂溶液黏度呈波动上升;疏水链碳数相同时,间隔基团碳数增加,磺酸盐双子表面活性剂溶液黏度先增大后减小,羧酸盐双子表面活性剂溶液则黏度减小,其中DS18-3-18和DC16-2-16增黏效果好;温度升高,DS18-3-18和DC16-2-16溶液黏度下降,但90℃时DS18-3-18溶液黏度(13.25mPa.s)大于DC16-2-16。微观结构研究表明,间隔基团碳数增大(s=2、3、4),DS18-s-18溶液胶束结构依次由球状变为片状直至球状,导致溶液黏度先增后降。温度升高,DS18-3-18溶液中片状胶束数目或堆积密度呈下降趋势,至90℃时,溶液中仍有联结完好的片状胶束存在,因此DS18-3-18具有较好的耐温增黏性。     

阴离子低聚表面活性剂吸附影响因素研究

采用浓度差减法研究了阴离子双子表面活性剂AK1048在含油石英砂上的吸附,考察了温度、盐度以及pH值等对其吸附特性的影响,发现随着表面活性剂体系盐度的增加,AK1048吸附量减小;随着pH值的增加,吸附趋势变化不明显;温度升高,GA 8-4-8吸附量减小;疏水基碳链长度越长,吸附量越大。上述结论为阴离子双子表面活性剂在三次采油领域的应用提供必要的理论支撑与指导。     

D301大孔吸附树脂吸附甘氨酸

通过静态吸附法研究了树脂D301对水溶液中甘氨酸的吸附行为。采用单因素实验法确定了最佳吸附条件为pH 7.5,温度35℃,时间45 min,吸附剂用量为0.1 g,在此条件下最大平衡吸附量可达794.81 mg·g^-1。同时探究了D301对甘氨酸溶液吸附的热力学行为,测得了303.15～318.15 K温度范围内的吸附等温线数据,用Langmuir、Freundlich、Temkin方程对此进行拟合,并根据热力学原理计算得到吸附过程中ΔH^θ、ΔG^θ、ΔS^θ值和吸附表观活化能。结果表明等温吸附平衡符合Langmuir等温线模型,其ΔH^θ 134.75 kJ·mol^-1,ΔG^θ-6.312 kJ·mol^-1, ΔS^θ 450.806 J·mol^-1·K^-1,E_a为81.27 kJ·mol^-1。研究结果表明D301对甘氨酸的吸附为化学吸附和物理吸附共存且为自发进行的吸热过程。     

双子季铵型表面活性剂合成工艺与性能表征

论文研究了采用四甲基丙二胺和溴代十二烷,在异丙醇作为溶剂的条件下合成双子表面活性剂C12-3-C12.2Br。采用红外光谱测定、熔点测定法对合成产物进行表征,并探讨不同反应时间、反应温度、反应物料比对生成产物的影响,同时还检测了产物的表面张力、临界胶束浓度等性质。实验结果表明,所合成的双子表面活性剂的产率是在12 h内随反应时间的增长而增大;在本实验条件下,反应温度对产率的影响就比较小;溴代十二烷过量更有利于反应进行,但过量太多也不利于反应的进行。测定表面张力可知产品的临界胶束浓度(CMC)是1.58mmol/L-1。     

松香基双羧酸盐双子表面活性剂的合成及性能

以脱氢枞胺及乙二胺四乙酸酐为原料简便合成了新型松香基双羧酸盐双子表面活性剂Na-DDEDTA,采用IR、 ¹H NMR 、 ¹³C NMR 等光谱对其结构进行了确证,研究了其表面活性性能。Na-DDEDTA表面活性剂比常规表面活性剂Na-DMA具有较低的临界胶束浓度及表面张力,其临界胶束浓度C_CMC及对应的表面张力分别为0.11 mmol/L及33.6 mN/m。两种表面活性剂的乳化性能相当,Na-DDEDTA泡沫性能比Na-DMA稍差,Na-DDEDTA亲水性更弱。松香基双子表面活性剂是一种良好的绿色化学品。     

Al-MCM-41介孔分子筛吸附喹啉的性能

在碱性条件下,采用水热晶化法,以偏硅酸钠为硅源,铝酸钠为铝源,CTAB为结构模板剂,成功合成出了含铝介孔分子筛Al-MCM-41。采用XRD、BET等手段对合成的Al-MCM-41进行表征,对柴油中的氮化物喹啉进行了吸附实验,考察了Al-MCM-41介孔分子筛对氮化物喹啉的吸附能力,探究了硅铝比为60的Al-MCM-41分子筛对喹啉溶液吸附的热力学和动力学行为,测得353.15～393.15 K 温度范围内的吸附等温线数据,用Langmuir、Freundlich方程对此进行拟合,并根据热力学原理计算得到吸附过程中的ΔH、ΔG、ΔS值和吸附表观活化能。结果表明, 硅铝比为60的Al-MCM-41具有较大的孔容、比表面积和较窄的孔径分布,结晶度和有序性高。等温吸附平衡符合Freundlich 等温线模型,其ΔH -0.7682 kJ·mol^-1,ΔG -28.1215 kJ·mol^-1, ΔS 73.2434 J·mol^-1·K^-1,吸附动力学符合Pseudo拟二级方程,E_a为2.8575 kJ·mol^-1。     

全氟烷基表面活性剂吸附特性研究

针对全氟烷基季铵碘化物(Le-134)、全氟烷基磷酸酯(Le-107)和全氟烷基聚醚(Le-180)三种表面活性剂水溶液的平衡态表面张力和吸附动力特性进行了研究。临界胶束浓度的大小关系为Le-180 (15×10^-6) -6) -6);饱和吸附量Г_max大小关系为 Le-107 相似文献   

王棕果壳粉吸附亚甲基蓝性能研究

研究了不同条件下王棕果壳粉对亚甲基蓝的吸附性能,得到吸附的最佳条件为王棕果壳用量10g/L,溶液pH值7,吸附时间30min,温度30℃,亚甲基蓝去除率可达98%。应用准一级动力学方程、准二级动力学方程、颗粒内扩散方程模拟了王棕果壳粉吸附亚甲基蓝的动力学过程,准二级动力学方程的R²值均大于0.9991,且平衡吸附量的计算值(q_e,cal)与实验值(q_e,exp)非常接近,说明该方程适合描述整个吸附过程。用Langmuir和Freundlich模型模拟吸附等温线,结果表明Langmuir方程(R²值均大于0.995)更适合描述此吸附过程,在303K下最大单层吸附量为17.36mg/g。计算了吉布斯自由能变(ΔG⁰)、焓变(ΔH⁰)、熵变(ΔS⁰)、吸附势(E)等热力学参数,ΔG⁰、ΔH⁰、ΔS⁰均小于0,说明此吸附过程是一个自发进行的、放热的、趋于有序的吸附过程。在相同温度下,随着亚甲基蓝初始质量浓度的增加,对应的E值逐渐降低。     

New Schiff Base Cationic Surfactants: Surface and Thermodynamic Properties and Applicability in Bacterial Growth and Metal Corrosion Prevention

A new series of cationic Schiff bases was synthesized and their chemical structures were confirmed using elemental analysis, infrared spectra and nuclear magnetic resonance. The surface properties of the surfactant solutions including surface tension, effectiveness, efficiency, critical micelle concentration, maximum surface excess and minimum surface area were calculated using surface tension-log concentration profiles. The surface parameters were strongly dependent on the hydrophobic chain length. The thermodynamic properties of the surfactants in their solutions showed the spontaneous behavior of both adsorption and micellization processes. The thermodynamic data revealed that the adsorption of the surfactant molecules at the air/water interface was more favorable than the micellization in the bulk of their solutions. The synthesized surfactants were evaluated with regard to their preventing the corrosion reaction of carbon steel in acidic media and also their acting as antibacterial biocides to inhibit bacterial growth. The data of corrosion and antibacterial evaluations showed the high efficiency and applicability of these compounds in these uses.     

Surface Activity of Monomeric and Polymeric (3-alkyloxy aniline) Surfactants

ABSTRACT

The adsorption and micellization processes of 3-alkyloxy aniline namely [3-decyloxy aniline (C10M), 3-dodecyloxy aniline (C12M) and 3-cetyloxy aniline (C16M)] and their polymers [C10P, C12P and C16P] have been investigated using surface tension (γ) measurements at different temperatures. The synthesized monomers and polymers have been characterized by IR and elemental analysis. The surface and thermodynamic parameters of these monomeric and polymeric surfactants are investigated. The results show that the critical micelle concentration (CMC) of the polymeric surfactants is lower than that of monomers. The CMC values decreases as the hydrophobic chain lengthens for both monomeric and polymeric surfactants. The surface parameters show the ability of monomeric and polymeric surfactants to adsorb at the air/water interface and decrease the surface tension. The thermodynamic parameters reveal that the micellization process is spontaneous for all investigated surfactants. The specific conductance measurements show that the specific conductance increases with increasing chain length of the substituted alkyl groups, the synthesized polymeric surfactants have higher values of specific conductance than the corresponding monomers and the specific conductance increases with rising solution temperature.     

Phenothiazine as inhibitor of the corrosion of cadmium in acidic solutions

The corrosion of cadmium in 0.5m HClO4, CH3COOH or 0.25m H2SO4 in the absence and presence of small amounts of phenothiazine (10–6–10–4 m) as an inhibitor has been studied using both electrochemical impedance spectroscopy (EIS) and Tafel-plot techniques. Measurements were carried out at cathodic, open circuit and anodic potentials at different temperatures. In HClO4 and H2SO4 solutions the inhibition efficiency increases as both the concentration of phenothiazine and the temperature are increased. The effect of temperature in CH3COOH solution gives an opposite effect, that is, a decrease in the inhibition efficiency with increasing temperature. This behaviour is attributed to competitive adsorption between the inhibitor molecules and the acetate ions at the metal–solution interface. Phenothiazine can be considered as an inhibitor of mixed type with more pronounced effects in the anodic direction. The thermodynamic parameters in HClO4 containing the inhibitor were evaluated using the Bockris–Swinkels adsorption isotherm with n=4 as the configurational function. These parameters reveal that phenothiazine is adsorbed on the cadmium surface in molecular form with a strong interaction between the metal and the inhibitor.     

Gemini Cationic Surfactants: Synthesis and Influence of Chemical Structure on the Surface Activity

Three cationic gemini surfactants were synthesized and characterized using different methods. Their surface activities were measured using surface and interfacial tension measurements. The effect of the spacer chain length on the surface activity, emulsification power and interfacial tension was studied. The thermodynamic parameters showed the tendency towards micellization and adsorption. The results showed that longer spacers increased the micellization tendencies of the surfactants, while shorter spacers increased the adsorption tendency at the air–water interface.     

Adsorption of some anionic surfactants on barite and at solution/Air interfaces

The adsorption behavior of synthesized anionic surfactants with the chemical structure RO-Ph-N=N-Ph-SO₃Na, where R is an octyl, dodecyl, or cetyl group, was analyzed by using a modified version of the Frumkin adsorption isotherm. The values of thermodynamic parameters (including free energy of micellization, ΔG _mic, and of adsorption, ΔG _ads) at the solution/air interface and the solid/liquid interface were calculated, and the relation between the adsorption of the surfactants at these interfaces was investigated. Studies of the surface properties of these synthetic surfactants showed that the length of the hydrocarbon chain of these surfactants plays a major role in determining their surface and thermodynamic properties and that there is a good relationship between the effectiveness of adsorption of the surfactant and its efficiency as a collector.     

Synthesis,Biological Study and Complexation Behavior of Some Anionic Schiff Base Amphiphiles

A novel series of anionic Schiff base amphiphiles were synthesized. The chemical structures of these compounds were elucidated using different spectroscopic tools. The surface and thermodynamic properties of the prepared Schiff bases were studied using classical measurements including surface and interfacial tensions. The surface parameters of these compounds, e.g., surface tension, critical micelle concentration, effectiveness, efficiency, maximum surface excess, minimum surface area, and interfacial activity showed their good surface activity. Their thermodynamic parameters of adsorption and micellization including free energy change of micellization and adsorption showed their tendency toward adsorption at the interfaces and also micelle formation at lower concentrations. The complexation behavior of the synthesized Schiff bases were study through the interaction of the Schiff base (IIIa; SBSD) with nickel chloride hexahydrate. All synthesized compounds in addition to NiCl₂·6H₂O and Ni Schiff Base complex have been evaluated for their antibacterial activity against Gram-positive and Gram-negative bacteria. The results of the biocidal activities showed high potent action of (Ni-III_a; Ni-SBSD) complex more than Schiff base IIIa; SBSD.     

Properties of the Quaternary Ammonium Salts with Novel Counterions

The Krafft temperatures, surface tensions and bacteriostatic efficacies of a series of dodecyl/tetradecyltrimethylammonium salts with new type counterions based on the general formula RN⁺(CH₃)₃?A^? were measured. The results revealed that the Krafft temperatures of the studied products were below 0?°C and the surface tensions of water were decreased to 22?C42?mN?m^?1 when applying these surfactants at a concentration range from 10^?2 to 10^?4?mol?L^?1. Moreover, the physicochemical parameters such as the saturation adsorption value, the minimum area per surfactant molecule and the standard thermodynamic parameters of adsorption and micellization varied with different counterions for these prepared quaternary ammonium salts. In addition, the bacteriostatic tests showed that the counterions with shorter carbon chain lengths were associated with greater efficacy for the novel quaternary ammonium salts studied here.     

Surface Activity,Thermodynamics of Micellization and Adsorption Properties of Quaternary Salts Based on Ethanolamines and Decyl Bromide

The surface-active properties of ionic-liquid type salts synthesized by the interaction of ethanolamines and decyl bromide have been studied. Surface tension as a function of concentration of the surfactant in aqueous solution was measured at 10, 20, 30 and 40 °C using a drop volume stalagmometer. From these measurements, the maximum surface excess concentration and the minimum area per molecule at the aqueous solution/air interface, the critical micelle concentration (CMC), the surface pressure at the CMC, and the standard thermodynamic parameters of adsorption and micellization were calculated. The structural effects on adsorption, micellization, and the effectiveness of surface tension reduction are discussed in terms of these parameters.     

Synthesis of Animal Fats Ethylolamides,Ethylolamide Phosphates and Their Petroleum-Collecting and Dispersing Properties

Ethylolamides of animal (beef and mutton) fats have been synthesized and modified with H₃PO₄. The identity of these products was confirmed by IR and NMR spectroscopy. The physical properties of the synthesized surfactants including interfacial tension and critical micelle concentration (CMC) were studied. From these measurements, the maximum surface excess concentration and the minimum area per molecule at the kerosene solution/water interface, the surface pressure at the CMC, and the standard thermodynamic parameters of adsorption and micellization were calculated. Ethylolamides and ethylolamide phosphates were obtained and tested as petroleum-collecting and petroleum-dispersing reagents. Some correlations between these parameters of the ethylol units and their ability to collect thin petroleum films from the water surface were revealed.     

Synthesis, Surface Active Properties of Novel Gemini Surfactants with Amide Groups and Rigid Spacers

A series of novel cationic gemini surfactants, bis-(N-(3-alkylamido-propyl)-N,N-dimethyl)-p-phenylenediammonium dichloride, were synthesized. The structures of the gemini surfactants were characterized by IR, ¹H NMR and ¹³C NMR. The Krafft temperatures of surfactants were determined through conductivity, the surface active properties in aqueous solution were studied at various temperatures by surface tension and conductivity. The thermodynamic functions of micellization process of the surfactants were also calculated by conductivity. The Krafft temperatures of the surfactants were 12, 13 and 28 °C. The values of CMC and Γ _max decreased with increasing the length of hydrophobic chains, but the values of CMC and α increased with increasing temperature. The process of micellization is a spontaneous, exothermic and entropy-driven process.