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1.
Dodecyl diphenyl oxide disulfonate with different counterions (C12MADS‐M, M = Na, Mg, Ca) were synthesized using dodecyl alcohol, diphenyl oxide and SO3 as reagents through alkylation–sulfonation–neutralization. The structure of the product was characterized by infrared spectroscopy and electrospray ionization‐mass spectrometry. The surface and interfacial prosperities were investigated. The critical micelle concentration (CMC) of C12MADS‐Na, C12MADS‐Mg and C12MADS‐Ca was 1.23 × 10?3, 5.25 × 10?4 and 5.37 × 10?4 mol/L, respectively. The surface tension at CMC (γCMC) of C12MADS‐Na, C12MADS‐Mg and C12MADS‐Ca was 43.2, 37.1 and 36.6 mN/m, respectively. Interfacial tensions between crude oil and C12MADS‐M aqueous solution gave only a small change in the calcium chloride concentrations ranging from 50 to 10,000 mg/L.  相似文献   

2.
Trimeric-type anionic surfactants (3CntaAm, where n is a hydrocarbon chain length of 8, 10, or 12) with three hydrocarbon chains and three carboxylate headgroups were synthesized from tris(2-aminoethyl)amine, and their properties were investigated by surface tension, electrical conductivity, dynamic and static light-scattering, fluorescence of pyrene, and emulsification power techniques. The critical micelle concentrations (CMC) of 3CntaAm were 0.00092–0.00834 mmol dm−3, and the surface tensions at the CMC were 33.3–39.9 mN m−1. The areas per molecule occupied by 3C10taAm and 3C12taAm were extremely small, showing they were highly compact at the air/water interface. In addition, adsorption or micellization behavior of 3CntaAm was estimated by parameters such as pC 20 (the efficiency of surface adsorption), CMC/C 20 (the ease of adsorption relative to the ease of micellization), and ΔG M o (Gibbs energy of micellization). Dynamic and static light-scattering mesurements of 3CntaAm showed a hydrodynamic radius of 45–61 nm above the CMC and aggregation numbers of 10–82 at the CMC, respectively. The fluorescence intensity ratio of the first to the third band in the emission spectra of pyrene started to lower from far above the CMC for 3C8taAm and 3C10taAm, and below the CMC for 3C12taAm. This suggests that loose micelles or premicellar aggregates are formed in solutions. Mixtures of aqueous solutions of 3CntaAm and toluene formed oil-in-water-type emulsions, and the stabilizing abilities were in the order of 3C8taAm>3C10taAm>3C12taAm. The degree of emulsification of 3C8taAm remained at 69% after 24 h of standing. Thus, 3CntaAm exhibited unique properties superior to monomeric or dimeric surfactants that were significantly influenced by their hydrocarbon chain lengths.  相似文献   

3.
The contact angles of saturated calcium dodecanoate (CaC12) solutions containing a second subsaturated surfactant on a precipitated CaC12 surface were measured by using the drop shape analysis technique. The subsaturated surfactants used were anionic sodium dodecylsulfate (NaDS), anionic sodium octanoate (NaC8), and nonionic nonylphenol polyethoxylate (NPE). Comparing at the critical micelle concentration (CMC) for each surfactant, NaC8 was the best wetting agent, followed by NaDS, with NPE as the poorest wetter (contact angles of 320, 420, and 620, respectively). Surface tension at the CMC increased in the order NaC8<NPE<NaDS, and subsaturated surfactant adsorption increased in the order NPE≪NaDS (1.4 vs. 84 μmole/g); adsorption of the NaC8 was not measurable. Interfacial tension (IFT) reduction at the solid-liquid interface due to subsaturated surfactant adsorption is an important contribution to contact angle reduction, in addition to surface tension reduction at the air-water interface. Surfactant adsorption onto the soap scum solid is crucial to solid-liquid IFT reduction and to good wetting. The fatty acid was the best wetting agent of the three surfactants studied, probably because calcium bridging with the carboxylate group synergizes surfactant adsorption onto the solid of the higher molecular weight soap. NaCl added to NaDS surfactant results in depressed CMC, lower surface tension at the CMC, decreased NaDS adsorption onto the solid, and decreased reduction in solid-liquid IFT. The contact angle is not dependent on the NaCl concentration for NaDS. The NaCl causes an increased tendency to form monolayers, which decrease air-water surface tension, but a decreased tendency to form adsorbed aggregates on the solid; the two trends offset each other, so wettability is not affected by added salt. The Zisman equation does not describe the wetting data for these systems well except for NaDS, further emphasizing the danger of ignoring solid-liquid IFT reduction in interpreting wetting data in these systems.  相似文献   

4.
The surface tension of disodium hexadecyl diphenyl ether disulfonate (C16‐MADS) was measured at different NaCl concentrations (0.00–0.50 mol L?1) and temperatures (298.0–318.0 K) using the drop‐volume method. The results show that, with increasing temperature, the critical micelle concentration (CMC) of C16‐MADS increases slightly, but the maximum surface adsorption capacity (Γmax) at the air–water interface decreases. When the concentration of NaCl was increased from 0.00 to 0.50 mol L?1, the CMC of C16‐MADS decreased from 1.45 × 10?4 to 4.10 × 10?5 mol L?1, but the surface tension at the CMC (γcmc) was not affected. When the concentration of NaCl was increased at 298.0 and 303.0 K, the Γmax of C16‐MADS increased. When the temperature was increased from 308.0 to 318.0 K, the surface excess concentration (Γmax) of C16‐MADS abnormally decreased from 2.26 to 1.41 μmol m?2 with increasing NaCl concentration. The micellization free energy () decreased from ?63.98 to ?76.20 kJ mol?1 with increase of temperature and NaCl concentration. The micellar aggregation number (Nm) of disodium hexadecyl diphenyl ether disulfonate (C16‐MADS) was determined using the molecule fluorescence probe method with pyrene as probe and benzophenone as quencher. The results show that an appropriate Nm could be measured only at surfactant concentration above the CMC. The Nm increased with an increase in C16‐MADS concentration, but the micropolarity in the micelle nucleus decreased. The temperature had little effect on Nm. Compared with typical single hydrophilic headgroup surfactants, aggregates of C16‐MADS exhibit different properties.  相似文献   

5.
A series of cleavable aryl sulfonate anionic surfactants were synthesized from cyanuric chloride, aliphatic amine and H-acid mono sodium salt. Their structures were identified by 1H NMR, Infrared Spectrum (IR) and Elementary Analysis (EA). Their critical micelle concentrations (CMC) in aqueous solutions at 25 °C were determined by a steady-state fluorescence probe method and a surface-tension method. With the increasing length of the carbon chain, the value of their CMCs and surface tensions under CMC (γ CMC) initially decreased and then reached a minimum (respectively 2.63 × 10−5 mol L−1 and 28.29 mN m−1) when the carbon number was 10. The CMC and γ CMC then increased when the carbon number was increased to 12. The results showed that, compared with sodium dodecyl benzene sulfonate (SDBS), such kinds of surfactants have much lower surface adsorption amounts and greater molecular areas on the aqueous surface.
Zhiyong HuEmail:
  相似文献   

6.
The critical micelle concentrations (CMC) of nine commercial nonionic surfactants (Tween 20, 22, 40, 60, and 80; Triton X-100; Brij 35, 58, and 78) and two pure nonionics [C12(EO)5 and C12(EO)8] were determined by surface tension and dye micellization methods. Commercially available nonionic surfactants (technical grade) usually contain impurities and have a broad molecular weight distribution owing to the degree of ethoxylation. It was shown that the surface tension method (Wilhelmy plate) is very sensitive to the presence of impurities. Much lower CMC values were obtained with the surface tension method than with the dye micellization method (up to 6.5 times for Tween 22). In the presence of highly surfaceactive impurities, the air/liquid interface is already saturated at concentrations well below the true CMC, leading to a wrong interpretation of the break in the curve of surface tension (γ) vs. concentration of nonionic surfactant (log C). The actual onset of micellization happens at higher concentrations, as measured by the dye micellization method. Furthermore, it was shown that when a commercial surfactant sample (Tween 20) is subjected to foam fractionation, thereby removing species with higher surface activity, the sample yields almost the same CMC values as measured by surface tension and dye micellization methods. It was found that for monodisperse pure nonionic surfactants, both CMC determination methods yield the same results. Therefore, this study indicates that precaution should be taken when determining the CMC of commercial nonionic surfactants by the surface tension method, as it indicates the surface concentration of all surface-active species at the surface only, whereas the dye method indicates the presence of micelles in the bulk solution.  相似文献   

7.
A series of novel dissymmetric gemini cationics surfactants was synthesized by three-step reactions. The dissymmetric gemini surfactants contain a dodecanoic acid dimethylethylamine ester as the constant cationic part on one side of the hydroxypropyl center and a similar other cationic part, but with a different acid length (from octanoic to palmitic), on the other side. The critical micelle concentration (CMC) and the effectiveness of surface tension reduction (γ CMC) were determined. The surface tension measurements of dissymmetric gemini surfactants showed good water solubility, and low CMC had great efficiency in lowering the surface tension and a strong adsorption at the air/water interface. The CMC was observed to increase initially with the increase of the ester bond alkyl group. They also showed good foaming properties and wetting capabilites.  相似文献   

8.
Dynamic surface tensions (γt)—measured by the maximum bubble pressure method—of some surfactants containing two hydrophilic (sulfonate) groups and two or three hydrophobic groups in the molecule (“gemini surfactants”), and of their mixtures with a nonionic surfactant or an amine oxide, have been measured at 25°C in 0.1 M NaCl. Linearity of the plots of surface pressure vs. square root of the surface age indicated that the systems studied were all diffusion-controlled. For the individual surfactant systems, the apparent diffusion coefficient decreases with an increase in the number of alkyl chains and the bulkiness of the surfactant molecules. For the mixtures, when interaction between the two surfactants is weak, γt at short times (t<1s) is close to that of the component with the lower surface tension; at longer times, it is closer to that of the component with the lower equilibrium surface tension. When interaction is strong, γt at short times is greater than that of either component. The molar ratio at which maximum effect on γt is observed depends upon the strength of the interactions between the two surfactants.  相似文献   

9.
Interfacial properties (surface tension, σ, and critical micelle concentration, CMC) of aqueous solutions of Tween 20 (polyoxyethylene sorbitan monolaurate) and/or bovine serum albumin (BSA) were evaluated. Temperature, Tween 20 concentration in the aqueous phase, BSA/Tween 20 ratio, and aqueous phase composition [water, ethanol (0.5, 1.0, and 2.5 M), and sucrose (0.5 M)] were the variables studied. The CMC of Tween 20 was determined by surface tension measurements (Wilhelmy plate method). The existence of BSA-Tween 20 interactions was deduced from surface tension measurements. The results show that the effect of temperature on CMC depends on the aqueous phase composition, but the σ value at CMC, σCMC, does decrease as temperature is increased. The CMC and σCMC values also depend on the aqueous phase composition. In aqueous ethanol solutions, the CMC increases, but σCMC decreases. However, in sucrose aqueous solutions, the CMC decreases, but there is no significant effect on σCMC. The BSA-Tween 20 interactions at the interface depend on both Tween 20 concentration (C) and solute in the bulk phase. In water and aqueous solutions of ethanol and sucrose, σ values decrease in the presence of protein at C<CMC but are practically independent of C at C>CMC. This is an indication that the interfacial characteristics of the mixed film are determined by either the protein or the lipid at the higher and lower protein/lipid ratio, respectively. In the intermediate region, the existence of BSA-Tween 20 interactions dominates the interfacial characteristics of mixed films.  相似文献   

10.
The surface properties [effectiveness of surface tension reduction (γCMC) critical micelle concentration (CMC), efficiency of surface tension reduction (pC 20), maximal surface excess concentration (Γmax), minimal area/molecule at the interface (A min), and the (CMC/C 20) ratio] of some well-purified N-alkanoyl-N-methyl glucamines and related polyol-based N-methyl amide-type surfactants, having the structural formula RC(O)N(Me)CH2(CHOH)xCH2OH, where RC(O)=undecanoyl, lauroyl, tridecanoyl, myristoyl, and x=1,3, and 4, were investigated at 25°C in distilled water and 0.1 M NaCl. Water solubility of these compounds does not simply depend on the number of hydroxyl groups in the molecule but is associated with the balance between intermolecular hydrogen bonds and hydrogen bonds formed with water molecules. The fundamental interfacial properties, such as CMC and γCMC and two thermodynamic parameters, standard free energy of adsorption and standard free energy of micellization, were found to be significantly dependent on the hydrophobic acyl chain rather than on the number of CHOH groups in the hydrophilic moieties. By contrast, the practical performance properties were greatly dependent on the nature of the hydrophilic group. As a whole, these surfactants had desirable foaming properties and efficient wetting abilities. Furthermore, synergism in foaming and wetting abilities was observed in a binary mixture of these surfactants with an alkyloxyethylene sulfate.  相似文献   

11.
烷基二苯醚二磺酸盐的制备与性能表征   总被引:14,自引:2,他引:12  
制备了一类由刚性基团联接的特殊双亲水基型阴离子表面活性剂———十二烷基二苯醚二磺酸钠(C12-MADS)、双十二烷基二苯醚二磺酸钠(C12-DADS)及十六烷基二苯醚二磺酸钠(C16-MADS),并对其性能进行了研究。25℃时3种烷基二苯醚二磺酸钠的CMC分别为1 16×10-3、1 10×10-5和4 51×10-4mol/L,γCMC分别为44 9、43 5和46 8mN/m,C12-MADS和C16-MADS在浓度分别为2 21×10-2和3 80×10-2mol/L时的胶束聚集数(Nm)分别为24和29。合成的烷基二苯醚二磺酸钠在质量分数高达0 1的无机酸、碱和盐溶液中保持稳定,发泡性低于烷基苯磺酸钠(LAS),但乳化性能优于LAS。C12-MADS在650mg/L硬水中去污比值为14 05%,明显高于LAS(7 18%)。C12-MADS和C12-DADS在4d后的生物降解度≥90%。该类表面活性剂具有优良的应用性能。  相似文献   

12.
In this research, a star‐shaped surfactant was synthesized through the chlorination reaction, alkylation reaction and sulfonation reaction of triethanolamine, which is composed of three hydrophobic chains and three sulfonate hydrophilic groups. The critical micelle concentration (CMC) of the surfactant was measured by the surface tension method, and the results showed that it had high surface activity with CMC of 5.53 × 10?5 mol/L. The surfactant was superior in surface active properties to the reference surfactants SDBS and DADS‐C12. The interfacial tension (IFT) of the studied crude oil–water system (surfactant concentration 0.1 g/L, NaOH concentration 0.5 g/L, and experimental temperature 50 °C) dropped to 1.1 × 10?4 mN/m, which can fulfil the requirement of surfactants for oil displacement. An aqueous solution of the surfactant and crude oil was emulsified by shaking, which formed a highly stable oil‐in‐water (O/W) emulsion with particle size of 5–20 μm. The oil displacement effect was almost 12%.  相似文献   

13.
Long-chain alkylnaphthalene sulfonates were synthesized by means of a Wurtz-Fittig reaction, and the basic properties were studied in water at 30°C. Through surface tension measurements, the following values were determined: the critical micelle concentration (CMC) and the surface tension at the CMC (γCMC). The following values were calculated: area per molecule at the CMC (ACMC), standard free energy change of micellization (ΔG mic o ), standard free energy of adsorption (ΔG ad o ), and the “efficiency” of a surfactant in reducing surface tension (pC20). The micelle aggregation numbers were measured through steady-state fluorescence-quenching methods. As the chain length of the hydrocarbon of n-alkylnaphthalene sulfonate increased, the Krafft temperature increased, the surface tension decreased, the value of CMC decreased, pC20 increased, ΔG ad o and ΔG mic o became more negative, and the micelle aggregation number increased. The results showed that sodium α-(n-decyl)naphthalene sulfonate (DNS) had a high pC20, low Krafft temperature, and lower CMC than other surfactants in this study. Thus, DNS and the other n-alkylnaphthalene surfactants studied exhibit desirable properties that may be of value in some fields such as detergency, oil recovery, and dyes.  相似文献   

14.
Linear alkanes with two pyrrolidone groups in both termini [abbreviation: 1,n-dipyrrolidonyl alkane (1,n-DPA) (n=3, 5, 9, and 12)] were synthesized. Their surface activities were evaluated in terms of surface tension, and compared with those of a few kinds of surfactants. Among 1,n-DPAs, 1,3-, 1,5-, and 1,9-DPAs were fully soluble in water and surface-active: especially 1,9-DPA showed a surface tension value of γW/A 32.8 mN/m at 5.9×10−2 mol/L or 1.7 wt% and was suggested as a nonionic surfactant with simple structure and moderate activity. Critical miceller concentration (CMC) of 1,9-DPA was 1.45×10−2 mol/L. Surface tension values of 1,5- and 1,9-DPAs were lower than those of the corresponding monofunctional pyrrolidones, N-propyl and N-pentylpyrrolidones. Minimum area per surfactant molecule (Amin) decreased with increase of methylene chain length in the series of 1,n-DPAs. The results suggested that 1,n-DPA favorably chooses a loop structure at air/water interface.  相似文献   

15.
Dehydroabietates with poly(ethylene oxide) chains of average m=12, 17, and 45 units [DeHab(E) m ] were synthesized. The adsorption at the liquid-vapor interface was measured, and the adsorbed amount and critical micelle concentrations (CMC) were determined. The foamability, the foam stability, wetting properties, and cloud points, with and without salt content, were studied. The results were compared with common linear alkyl ethoxylates, nonylphenol ethoxylates, and cholesterol ethoxylates. The dehydroabietic acid as hydrophobe was found to result in the same CMC as a linear dodecyl chain. DeHab(E)45 was found to be insoluble above 400 mg/L, but the surface tensions at lower concentrations were similar to those of the C11–13E38–40 surfactants, which exhibit CMC in aqueous media. The foaming behavior of the DeHab(E)12 and DeHab(E)17 surfactants was about the same as for common linear C n E m surfactants. The foamability as well as the foam stability increased with ethylene oxide (EO) chain length. The cloud point was depressed by increased salt concentration and increased with the number of EO units in the head group. The cloud point was significantly lower than for the corresponding surfactant with a dodecyl chain with similar EO chain length. The wetting results, obtained by measuring the contact angle at similar surface tensions, indicate that surfactants of the DeHab(E) m type are more efficient wetting agents than both disaccharide sugar surfactants and C n E m type surfactants.  相似文献   

16.
The equilibrium and dynamic surface tension of three sulfosuccinate surfactants at the air/aqueous solution interface were investigated. Wilhelmy plate method was used to determine critical micelle concentration (CMC) and the equilibrium surface tension (γ eq). The dynamic surface tensions in the range 10–100 s were measured by maximum bubble pressure method. The well-known Ward–Tordai equation was employed to analyze the adsorption of the sulfosuccinate surfactants. The parameters and effective diffusion coefficients (D eff) of dynamic surface tension have been calculated and analyzed. The equilibrium surface tension results showed that disodium laureth (3) sulfosuccinate (AEO3-SS), disodium laureth (6) sulfosuccinate (AEO6-SS) and disodium alkyl ethoxy glucoside sulfosuccinate (AEG-SS) are surfactants possessing strong surface activity, adsorbing to the interface rapidly and their γ eq values were in the range 25–32 mN/m. CMC of the three surfactants increases with the number of hydrophilic groups and AEO3-SS has the lowest CMC. According to the values of some dynamic surface tension parameters, AEG-SS is the most hydrophilic surfactant of them and AEO3-SS is energetically more favorable to adsorb to the interface than the others. According to Ward–Tordai equation, the D eff values were calculated, the adsorption mechanism was diffusion controlled at short times and toward the end good evidence was found for an activated-diffusion mechanism with an energy barrier.  相似文献   

17.
A series of new cationic surfactants, bis-quaternary ammonium salts, were prepared from tert-alkylamine and a product of the reaction of epichlorohydrin with decyl- and dodecylamine, and their surface-active properties were measured. Specifically, the critical micelle concentration (CMC), effectiveness of surface tension reduction (γCMC), surface excess concentration (Γ), area per molecule at the interface (A), and standard free energies of adsorption (ΔG ads o) and of micellization (ΔG mic o) were determined. All these surfactants showed good water solubility and low CMC, more than one order of magnitude lower than those of corresponding mono-alkylammonium salts. They also showed good foaming properties but worse wetting capabilities. Many of these compounds had antimicrobial activities against gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and yeast (Candida albicans), but they were not active against molds.  相似文献   

18.
A novel homologous series of 1-N-l-phenylalanine-glycerol ether surfactants was synthesized in satisfactory yields via reaction of epichlorohydrin with aliphatic alcohols with alkyl chains of 10–15 carbon atoms. Structural assignment of the new compounds was made on the basis of elemental analysis and spectroscopic data. Critical micelle concentration (CMC), surface tension at the CMC (γCMC), surfactant concentration required to reduce the surface tension of the solvent by 20 mN/m (pC20), and the interfacial area occupied by the surfactant molecules (Amin) were determined from aqueous surface tension measurements using the Wilhelmy plate technique.  相似文献   

19.
In this work, a novel series of zwitterionic gemini surfactants with different hydrophobic tails were synthesized and characterized. The physico‐chemical properties of these products (such as surface tension, oil/water interfacial tension, foaming ability, and the wetting ability of paraffin‐coated sandstone) were fully studied. The CMC of the synthesized surfactants ranged from 2.17 × 10?4 mol L?1 to 5.36 × 10?4 mol L?1 and corresponding surface tension (γCMC) ranged from 26.49 mN m?1 to 29.06 mN m?1, which showed excellent efficiency among the comparison surfactants. All the products can reduce the interfacial tension to a relatively low level of about 0.1–1.0 mN m?1. Additionally, results from applying different hydrocarbons suggested that the synergy will be clearer and oil/water interfacial tension will be lower if the oil components are similar to the surfactants. Contact angle and foaming measurements indicated that the surfactants exhibited good wetting and foaming abilities. The results of oil flooding experiments using an authentic sandstone microscopic model showed that C‐12 and CA‐12 could effectively improve the displacement efficiency by 21–29 %.  相似文献   

20.
Maleic acid alkyl ester and N-alkyl maleamic acid monomers (RnMa and RnMaAm; n is alkyl chain length; n=6, 8, 10, 12, 14) were synthesized by the reaction of maleic anhydride with alkyl alcohol or alkylamine. The telomerization of RnMa or RnMaAm in the presence of alkanethiol as a chain transfer agent gave telomer-type anionic surfactants (xRnMa, xRnMaAm; x is total average number of alkyl chains; x=2.8–3.3) having multialkyl chains and multicarboxylate groups. Their surface-active properties were investigated by several techniques such as surface tension, foaming property, and emulsification power measurements. Critical micelle concentrations (CMC) of xRnMa were 1/110–1/14 of those of RnMa with the same alkyl chain length. xRnMa and xRnMaAm gave higher efficiencies in lowering the surface tension than RnMa and RnMaAm in aqueous solutions. In particular, the surface tension of 3.2R12MaAm was 24.4 mN m−1 at the CMC. Foaming abilities and foam stabilities of xRnMa and xRnMaAm were higher than those of RnMa and RnMaAm. The addition of 300 ppm of Ca2+ to the aqueous solutions rendered the telomers less surface active. Shaking the aqueous solutions of telomers with toluene emulsified them. The highly stable oil-in-water type emulsion was formed by using 3.0R10MaAm and 3.2R12MaAm, and the degree of emulsification was kept at a level of about 80% after 60 min of standing. Thus, telomer-type surfactants showed excellent surface activities that were superior to the corresponding monomers as well as to conventional surfactants. The relationship between alkyl chain length of the telomers and the properties of surface tension, foaming, and emulsification was unclear.  相似文献   

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