Surface activity and cleaning performance of rosin-based quaternary ammonium salt type asymmetric Gemini surfactants

Rosin,a renewable and abundant resource,has been extensively processed and chemically modified to endow it with special properties,especially in the surfactant industry.In this study,four rosin-based quaternary ammonium asymmetric gemini surfactants(RGS-2-n)with different alkyl chain lengths(n=12,14,16,18)were synthesized using a simple two-step method based on dehydroabietylamine as the raw material.The feasibility of these surfactants for cleaning purposes was comprehensively evaluated,suggesting that the surfactants own high surface activity and good cleaning performance.Furthermore,by successfully introducing the amine group of dehydroabietylamine into the hydrophilic group of the surfactants,we avoided its potential harm to the environment and water pollution.Density functional theory proves rosin-based gemini surfactants with asymmetric structure can further improve cleaning efficiency.Overall,our findings suggests that RGS-2-n surfactants are promising and sustainable candidates for cleaning electric plates,and provide new opportunities for rosin application in the electric industry.

Comparative studies on flotation of aluminosilicate minerals with Gemini cationic surfactants BDDA and EDDA

Gemini quaternary ammonium salt surfactants, butane-a, co-bis（dimethyl dodeculammonium bromide） （BDDA） ethane-a, fl-bis（dimethyl dodeculammonium bromide） （EDDA） were adopted to comparatively study the flotation behaviors of kaolinite, pyrophyllite and illite. It was found that three silicate minerals all exhibited good floatability with Gemini cationic surfactants as collectors over a wide pH range, while BDDA showed a stronger collecting power than EDDA. FTIR spectra and zeta potential analysis indicated that the mechanism of adsorption of Gemini collector molecules on three silicate minerals surfaces was almost identical for the electronic attraction and hydrogen bonds effect. The theoretically obtained results of density functional theory （DFT） at B3LYP/6-31G （d） level demonstrated the stronger collecting power of BDDA presented in the floatation test and zeta potential measurement.

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

The synthesis and surfactant activities of two new cationic gemini surfactants containing triazole compound as spacer were described. Their critical micelle concentrations (CMC), which are 1.8×10-4 mol/L and 3.9×10-4 mol/L respectively, are much lower than that of conventional surfactant cetyltrimethyl ammonium chloride (CTAC). In addition, compared with some gemini surfactants containing phenylene, xylylene and stilbenyl as spacer, this new kind of surfactants has good solubility in water at room temperature because of containing more hydrophilic groups or atoms in molecules.

Synthesis and Properties of Gemini Cationic Surfactants with Amide Spacers

Four gemini cationic surfactants {N,N′-di[2-(lauryldimethylamino)acetyl]polymethylenediamine dichloride, LAA-s-LAA, s=2,3,4,6} were synthesized by using four bis(α-chloroacetamide)s and N,N-dimethyllaurylamine, respectively. The molecular structures were characterized by means of IR, ~ 1H NMR, \{~ ~13 C NMR\} and MS, and the behavior of their aqueous solutions was studied. The critical micell concentrations(CMC) of LAA-s-LAA were one order of magnitude lower than that of dodecyltrimethyl ammonium chloride(DTAC). With the change of the length of spacer chain(s), their CMC values change, and CMC reaches the top value at s=4.

Phase Separation and Microstructure of Mixed Surfactants Solution Containing Cationic Geminis and Traditional Anionic Surfactant

The properties of aqueous two-phase system (ATPS) of mixed solution containing gemini cationic surfactant trimethylene-1,3-bis(dodecyldimethyl ammonium) bromide (12-3-12, 2Br-) and traditional anionic surfactant sodium dodecyl sulfate (SDS) with or without added salt have been studied. An ATPS is formed in a narrow region of the ternary phase diagram different from that of traditional aqueous cationic-anionic surfactant systems. In ATPS region, the lowest total concentration of surfactants varies with the mixing ratio of geminis to SDS. Photographs obtained from freeze-etching, negative-staining and transmission electron microscopy show that the microstructures of two phases are different from each other. Micelles and vesicles can coexist in a single phase. The addition of salts can change the phase diagram of ATPS. Furthermore, the added salts promote the aggregation of rod-like micelles to form coarse network structure that increase the viscosity of solutions. The negative ions of the added salts are the determining factor.

Comparative studies on flotation of illite,pyrophyllite and kaolinite with Gemini and conventional cationic surfactants

To search a novel class of effective silicate mineral collectors,the Gemini quaternary ammonium salt surfactant(butane-α,ω-bis(dimethyl dodeculammonium bromide),12-4-12) and its corresponding conventional monomeric surfactant(dedecyl trimethyl ammonium bromide,DTAB) were adopted to comparatively study the flotation behaviors of illite,pyrophyllite and kaolinite. Three silicate minerals with the Gemini surfactant as collector reveal floatability far better than with the corresponding traditional one. At pH 6,the best recoveries of illite,pyrophyllite and kaolinite with 3.5×10-4 mol/L 12-4-12 are 99.2%,91.7% and 99.6%,respectively. The fluorescence and contact angle measurement were also conducted for the further investigation of surfactants aggregation behavior and silicate mineral surface hydrophobic properties. FTIR spectra analysis and electrokinetic analysis show that the mechanism of adsorption of collector molecules on mineral surfaces is almost identical for the electronic attraction and hydrogen bonds effect. The superior collecting power of dimeric collector may be attributed primarily to its special structure and its essential properties.

Novel Piperazine-based Gemini and Bola Surfactants

A series of piperazine-based Gemini and Bola surfactants were synthesized. Gemini 1 and 5 have well surface activities. Their critical micelle concentrations （cmc） is 6.47×10^-4 mol/L and 1.17×10^-3mol/L, respectively. Bola surfactants 2 and compound 3, possessing better water solubility, have lower surface activities. Calculation, carried out by MM2 energy minimization, showed that compound with more hydrophobic chains in a spacer of limited length is difficult to be synthesized.

Synthesis and Surface Activity of Biquaternary Ammonium Salt Gemini Surfactants with Ester Bond

The synthesis and surface activity of gemini surfactants with ester bond as spacer are described. Their critical micelle concentrations （CMC） are much lower than that of conventional surfactants, i.e., 1.62×10^-5, 1.38×10^-5, 1.28×10^-5 mol·L^-1 for gemini Ⅰ, Ⅱ and Ⅲ respectively. Surface tension at the CMC of gemini Ⅰ, Ⅱ and Ⅲ were 36.4, 38.5, 41.2 mN · m^-1. The physico-chemical properties such as Krafft points, foaming abilities and emulsifying power were also investigated. It is found that the title compounds have low Krafft points and show good solubility in water. The gemini surfactants synthesized also exhibit good foaming properties and excellent emulsifying power toward toluene. The foaming abilities and emulsifying power increase with the increase in carbon number of hydrophobic chain, and this might be caused by the sheer viscosity of different gemini surfactant solution.

Biphasic Catalytic Hydroformylation of 1-Dodecene in Micellar System with Cationic Gemini Surfactants

The promotion effect of cationic gemini surfactants for the hydroformylation of 1-dodecene in the organic/aqueous biphasic catalytic system is reported. The hydroformylation reaction in the presence of gemini surfactant occurred with higher turnover frequency and higher selectivity for linear aldehyde than using conventional monomeric surfactant CTAB.

Micellar Exchange Kinetics of Quaternary Ammonium Type Gemini Surfactants Monitored by Nuclear Magnetic Resonance

The dynamic NMR （DNMR） method was used to detect kinetic parameters of the molecular exchange process between monomers in bulk solution and those in the micelle for Gemini surfactants, 12-s-12 and 14-s-14 （s 2, 3 and 4）. The escape rate constant, k^- , was derived based on the simplified equations of DNMR theory, and the apparent activation energy of escape, Ea^- , was obtained based on the Arrhenius equation through temperature variation experiments. Results show that the orders of magnitude of k^- for 14-s-14 and 12-s-12 are respectively 10 and 103 s-1, Ea^- of 14-s-14 and 12-s-12 are respectively 54.04-73.64 and 33.42-47.09 kJ/rnol. Furthermore, k increases and Ea^- decreases with the spacer length growing. In combination with the rnicro-polarity measurements, it was revealed that molecules of 14-s-14 and 12-s-12 have to experience conformation changes when escaping from the rnicelles. The two-step molecular exchange mechanism for Gemini surfactants was therefore supported.

<i>N</i>-Acetylated Gemini Surfactants: Synthesis, Surface-Active Properties, Antifungal Activity, and Ecotoxicity Bioassays

A series of N-acetylated cationic gemini surfactants (3a-e) having dimeric structures derived from tertiary amines were synthesized. Their antifungal potency and surface properties were determined. It also studied the acute toxicity of the molecule with the best performance and the best water solubility (3e) through Chlorella vulgaris and Daphnia magna bioassays. The results were compared to those obtained for a commercially available reference compound 2-(thiocyanomethylthio) benzothiazole (TCMTB). Parameters such as surface tension (&#978CMC), critical micelle concentration (CMC), surface excess concentration (Γ), and area per molecule (A) were determined. The resulting values indicated that the five gemini surfactants are characterized by good surface-active and self-aggregation properties. All surfactants were tested to evaluate their antifungal activity. Six fungal strains were used to conduct the study. The minimum inhibitory concentration (MIC) value was measured by the fungal growth inhibition. The results of the MICs were compared with two commercially available reference compounds (Fluconazole and TCMTB). The least active molecule was 3e, but 3b and 3d were found to be the most potent compounds with a similar activity for all strains. Candida albicans was the most sensitive one. In contrast, Aspergillus niger was resistant. Ecotoxicity of gemini 3e was assessed: the commercial formulation (TCMTB) was between three and four orders of magnitude more toxic than the gemini one for the biological species tested.

甜菜碱/AOS/Gemini季铵盐三元复合型泡排剂的研制与性能评价

泡沫排液技术是保障气井产量的重要手段,研发高性能的泡排剂极其关键。为适应高矿化度、高凝析油含量及高温等苛刻气井环境,以椰油酰胺丙基羟基磺基甜菜碱(CHSB)作为主剂,α-烯基磺酸钠(AOS)和合成的Gemini阳离子表面活性剂CAGB作为辅剂制备了一种高效环保的三元泡排体系。结果表明,三元复配体系AOS/CAGB/CHSB在摩尔比为12∶3∶35、总量为20 mmol/L时性能最优,泡沫体积和半衰期分别达到360 mL和30.27 min;在含有30%甲醇的泡排剂溶液中,测得的携液率最高可达31%,发泡率为95%;在含有0%~50%凝析油的泡排剂溶液中,三元泡沫体系表现出良好的性能,其中在凝析油含量为20%时,测得的携液率最高可达38%,发泡率为95%;优选的三元复配体系AOS/CAGB/CHSB对盐离子耐受性较差,加入螯合剂(氨三乙酸三钠(NTA))后,三元复配体系在矿化度为150 g/L的溶液中仍能稳定发泡和携液;温度大于50℃时,泡沫的携液率也逐渐增加,温度在90℃时,携液率在95%以上。此外,通过表面张力测试、泡沫微观结构观察也证实了该泡排剂体系存在的协同效应使其起泡、稳泡和泡沫携液能力得到有效提升。

Molecular Dynamics Simulation for the Effect of Chain Length of Spacer and Tail of Cationic Gemini Surfactant on the Complex with Anionic Polyelectrolyte

Interaction of anionic polyelectrolyte with cationic gemini surfactant has been investigated by coarse-grained molecular dynamics simulation.Polyelectrolyte facilitates the oppositely charged ionic surfactants to aggregate by suppressing the electrostatic repulsion between ionic head groups leading to the formation of micellar complex.With addition of surfactant,the conformation of polyion chain changes from stretched to random coiled to spherical,and at the same time more free micelles are formed by surfactants in mixtures.Increasing the length of spacer or tail chain in gemini surfactant will weaken its interaction with polyelectrolyte and simultaneously strengthen its tendency to self-assemble.The simulation results are consistent with experimental observations and reveal that the electrostatic interaction plays an important role in the interaction of polyelectrolyte with gemini sur- factant.

Interaction of DNA with Cationic Gemini Surfactant Trimethylene-1, 3-bis （dodecyldimethyl-ammonium bromide） and Anionic Surfactant SDS Mixed System

The interaction of DNA with cationic gemini suffactant trimethylene-1,3-bis （dodecyl dimethyl-ammonium bromide） （12-3-12） and anionic surfactant sodium dodecyl sulfate （SDS） mixed system has been investigated by measuring the fluorescence, zeta potential, UV-Vis spectrum, and circular dichroism. In the absence of SDS, owing to the electrostatic and hydrophobic interactions, 12-3-12 forms micelle-like structure on the DNA chain before the micellization in bulk phase. For the mixed system of 12-3-12 and SDS, the negative charges on SDS can compete against DNA to bind with cationic 12-3-12 because of the stronger interaction between oppositely charged surfactants, and thus, the catanionic mixed micelles are formed before the formation of DNA/12-3-12 complexes. There-after, the positive charges on the mixed micelles bind with DNA, and thus, the change of the zeta potential from negative to positive is distinctly different from the system without SDS. Meanwhile, the existence of SDS postpones the exclusion of ethidium bromide （EB） from DNA/EB complexes. The conformation of DNA undergoes a change from native B-form to chiral ψ-phase as binding with 12-3-12 process. Upon adding SDS to the DNA/12-3-12 complex solution, however, DNA is released to the bulk and the ψ-phase returns to B-form again.

Interaction in Binary Mixtures of Gemini Surfactant G12-6-12 and CTAB by NMR

The interaction between N, N′-bis（dimethyldodecyl）-1,6-hexanediammoniumdibromide （G12-6-12） and cetyltrimethylammonium bromide （CTAB） in D20 aqueous medium has been investigated by NMR at 298 K. The G12-6-12 and CTAB are about 0.773 and measured critical micelle concentration （cmc） of 0.668 mmol/L, respectively. The cmc^＊ （cmc of mixture） values are less than CMC^＊ （cmc of ideally mixed solution） in the mixed system, and the interaction parameter βM〈0 at different molar fractions α of G12-6-12 in the mixed systems, but just when α≤0.3, cmc^＊ values are much smaller than CMC^＊, and βM satisfies the relation of ｜βM｜〉｜ln（cmc1/cmc2）｜ （cmcl： cmc of pure G12-6-12 and cmc2： cmc Of pure CTAB）. The results indicate that there exists synergism between G12-6-12 and CTAB, and they can form mixed micelles, which is further proven by 2D NOESY and self-diffusion coefficient D experiments. There are intermolecular cross peaks between G12-6-12 and CTAB in 2D NOESY, and the radius of micelles in mixed solution is bigger than that in G12-6-12 pure solution in D experiments, indicating there are mixed micelles. However, when α〉0.3, we find that cmc^＊≈CMC^＊, βM≈0, obviously, the two surfactants are almost ideal mixing fitting the pseudo-phase separation model and regular solution theory.

Innovative surfactant of Gemini-type for dissolution mitigation of steel in pickling HCl medium

A new surfactant of Gemini-type,N,N'-((phthylbis(oxy))bis(ethane-2,1-diyl))bis(N,N-dimethyldodecan-1-aminium bromide)is prepped&confirmed.The dissolution suppression impact of the new compound on steel is performed in 1 mol·L^(-1)HCl environment by means of chemical and electrochemical methods.The prepared surfactant is an agreeable dissolution inhibitor for steel.The mitigation efficacy rises with the quantity of the compound.The surfactant belongs to inhibitors of mixed-type.The adsorption of the synthesized compound followed the Langmuir's model.The negative magnitudes of bothΔG_(ads)^(θ) andΔH^(adsθ)indicate that the adsorption process proceeds from its own accord and exothermic.The mechanism of adsorption is elucidated by scanning microscopy.It is established that the transfer resistance(R_(ct))value rose,where the value of the phase element(CPE)reduced with the amount of synthesized inhibitor.According to the experimental data arrived by surface tension measurements,the prepared compound is a powerful active agent at the air/water boundary.

Synthesis of Cardanol Sulfonate Gemini Surfactant and Enthalpy-Entropy Compensation of Micellization in Aqueous Solutions

A novel cardanol sulfonate Gemini surfactant with high surface properties was synthesized by cashew phenol, 1,3-dibromopropane and chlorosulfonic acid through three steps procedure of etherification, sulfonation and neutralization. A surface tension method was employed to investigate the thermo-dynamic properties of micellization in aqueous solution for cardanol sulfonate Gemini surfactant synthesized in laboratory. As a result, the micellization of cardanol sulfonate Gemini surfactant in aqueous solutions is spontaneous and entropy-driven. The micellization process is enthalpy-entropy compensated with the compensation temperature (Tc) of 308 ± 1 K.

氨基甘油Gemini表面活性剂的合成与性质研究

以脂肪胺、缩水甘油及1,3-二氯-2-丙醇为原料,合成了一系列甘油胺为头基、羟基丙烷为连接基的非离子型Gemini表面活性剂。通过核磁共振(1HNMR、13CNMR)、高分辨质谱(HRMS)、傅里叶红外光谱(FT-IR)对产物的结构进行表征,并研究了它们的表面活性、润湿性、乳化性、起泡性和抑菌活性。结果表明,8-3(OH)-8在2.02 mmol/L时有较好的降低表面张力的效果,12-3(OH)-12具有最好的发泡性以及乳化性;8-3(OH)-8和12-3(OH)-12在水溶液中均呈稳定的纳米分散体系;8-3(OH)-8对金黄色葡萄球菌和大肠杆菌都有最好的抑菌效果,在40μg/mL时抑菌率达90%以上。羟基丙烷为连接基的脂肪氨基甘油Gemini表面活性剂具有良好的应用前景。

Dynamic Study of Gemini Surfactant and Single-chain Surfactant at Air/Water Interface

Molecular dynamics (MD) simulation are used to study the properties of gemini surfactant of ethyl-α,ω-bis(dodecyldimethylammonium bromide) (C12C2C12) and dodecyl- trimethylammonium bromide (DTAB) at the air/water interface, respectively. In the two systems, the surfactant concentrations are both 28 wt. %, and other conditions are also the same. After reaching the thermodynamic equilibrium, the concentration profiles, the radial distributions functions (RDF) and the mean squared displacement (MSD) are investigated. The results reveal that the surface activity of C12C2C12 surfactant is higher than DTAB surfactant.

Gemini阳离子/含氟阴离子表面活性剂混合体系的界面润湿调控及解水锁机制研究

为有效解决低渗透致密砂岩气藏开采普遍存在的水锁伤害问题,研究了Gemini阳离子表面活性剂双季铵盐BQ-16和含氟阴离子表面活性剂全氟辛基磺酸钾(PPS)在降低表面张力和润湿调控方面的协同作用,并探究了BQ-16/PPS表面活性剂混合体系的润湿调控及解水锁机制。结果表明,当PPS的摩尔分数(α_(PPS))为0.7时,BQ-16/PPS表面活性剂混合体系的表面张力达到最低,低于任一纯组分,此时BQ-16/PPS表面活性剂混合体系接近电中性;BQ-16和PPS在岩心表面润湿调控方面表现出协同效应,当BQ-16/PPS表面活性剂混合体系总浓度为1×10^(-4)mol·L^(-1)、α_(PPS)为0.7时,盐水滴接触角最大,达到84.23°;BQ-16/PPS表面活性剂混合体系(α_(PPS)=0.7)在石英砂表面的吸附过程符合准二级动力学方程和Freundlich等温吸附模型,低浓度时为单分子层吸附,高浓度时为多分子层吸附;BQ-16/PPS表面活性剂混合体系(α_(PPS)=0.7)可将岩心的液体饱和度降至0.410,并将渗透率恢复值提高至0.78,说明BQ-16/PPS表面活性剂混合体系可有效解决水锁伤害,这主要与混合体系能够显著降低表面张力并通过在岩心表面的吸附改变岩心表面润湿性有关。