Anionic surfactants mixtures

In cases where 2D NMR experiments are insufficient for a complete analysis of anionic surfactant mixtures, LC-NMR may provide better information. Characterisation of fatty alcohol ethoxylate (FAE) based oligomeric surfactants by on-line 2D (GCOSY, TOCSY and Homo 2DJ) stopped-flow HPLC- H NMR has been described [655,656]. The analysis of a typical mixture comprising three components (PEG and PEOs with different end-groups) is shown in Figure 7.34. In this representation, the 111 NMR frequency domain is in the... 

At the termination of the activity period, each participant s hands were held over a bowl and doused with 250 mL of a dilute dioctyl sodium sulfosucci-nate (anionic surfactant) mixture. This soap wash was followed by a 250-mL rinse with deionized water. The soap and water fractions were stored together in the same container. Fifteen grams of sodium chloride were added to the container to facilitate phase separation. The chlorpyrifos was partitioned with 200 mL of ethyl acetate, which was also used to rinse the bowl. The ethyl acetate extract was later analyzed for chlorpyrifos content. The amount of test substance removed was used to assess adult hand exposures and dose and also to assess the theoretical amount of test substance removed when children put their hands in their mouths. 

Graciaa A. et alii, The Partitioning of Nonionic and Anionic Surfactant Mixtures Between Oil/Microemulsion/Water Phases , n° SPE 13 030, Houston, 1984. 

As an example of an anionic surfactant mixture frequently contained in detergent formulations, an AES blend with the general formula C H2 i i—O—(CH2—CH2—O) —SO3 was examined in the negative FLAMS mode. Because of the considerable differences observed between both API ionisation mode overview spectra, the ESI—FIA—MS(—) and the APCI—FIA—MS(—) spectra are reproduced in Fig. 2.5.3(a) and (b), respectively. Ionisation of this blend in the positive APCI—FIA—MS mode, not presented here, leads to the destruction of the AES molecules by scission of the O—SO3 bond. Instead of the ions of the anionic surfactant mixture of AES, ions of AE can then be observed imaging the presence of non-ionic surfactants of AE type. 

The second factor, namely the head group interaction, can also influence the surface properties of mixed surfactant markedly. In particular, anionic/catlonic surfactant mixtures exhibit the largest effect (17,18). In nonionic/anionic surfactant mixtures, synergistic effects can still take place to a significant extent, as revealed in Figure 3 (pH 10.9, nonionic amine oxide with anionic long chain sulfate), since insertion of nonionic surfactant molecules into an ionic surfactant molecular assembly minimises electrostatic repulsion (19). 

Adsorption of Binaiy Anionic Surfactant Mixtures on a-Alumina... 

LOPATA ET AL. Adsorption of Binary Anionic Surfactant Mixtures... 

Nonionic surfactants are more tolerant of the presence of cationic surfactants than anionic surfactants. Mixtures of the two are sometimes used in the production of specialty determents that are powerful antistatic products. 

Lalonde, J. Witte, E.J. Oconnell, M.L. Holliday, L. Protease stabilization by highly concentrated anionic surfactant mixtures. Journal of the American Oil Chemists Society 1995, 72 (1), 53-59. 

Salkar, R.A. Mukesh, D. Samant, S.D. Manohar, C. Mechanism of micelle to vesicle transition in cationic-anionic surfactant mixtures. Langmuir 1998, 14, 3778-3782. 

Garcia-Delgado, R.A., Cotoruelo, L.M., and Rodriguez, J.J. (1992). Adsorption of anionic surfactant mixtures by polymeric resins. Sep. Sci. Technol., 27, 1065-76. Pendleton, P., Wu, S.H., and Badalyan, A. (2002). Activated carbon oxygen content influence on water and surfactant adsorption. J. Colloid Interface Sci., 246, 235-40. 

High-concentration flowable anionic surfactant mixtures containing alkyl ether sulfates and alkyl sulfates... 

U.S. 4,435,317 (1984) Gerritsen et al. (Procter Gamble) Tertiary anionic surfactant mixture Mg level corresponds to alkyl sulfate level Maximum foam stability... 

Only the apphcation of LC-MS analysis can be conceived of as reliable surfactant analysis. To elaborate determination methods for the analysis of the anionic surfactant mixture of alkyl ethoxysuUates (AES) APCI and ESI-MS(-t/-) studies combined with in-source MS/MS examinations were performed and results were compared (cf. Pig. 15.4 and 15.5 and 15.3.3.2 ESI, surfactants). APCI fragment ion spectra revealed the aUcyl chain length and the number of ethoxylate moieties therefore APCI was found to be the method of choice [326]. To confirm determination methods apphed in surfactant analyses an inter-laboratory comparison study of LC-MS techniques and enzyme-hnked immunosorbent assay for the determination of surfactants in wastewaters was performed in seven laboratories. The quantitative determination of the non-ionic NPEOs, AEOs, coconut diethanol amides (CDEAs) and the anionic LAS, NPEO-sulfates and the secondary alkane sulfonates (SAS) was performed under APCI or ESI-interfacing conditions in positive or negative... 

As demonstrated (cf. Fig. 15.1 and 15.2) with the results of ionisation observed in the spectra of the non-ionic surfactant mixtures of AEOs or APOs or for ionisation of the anionic surfactant mixture of AES (cf Fig. 15.3), if APCl or ESI interfaces were applied, both API interface types presented considerable differences in the ionisation processes. These differences were in both the type of ions and the efficiency of ionisation, i.e., either high molecular or low molecular compounds were favoured in ionisation and no ionisation takes places with the one interface whereas the other interface type ionises the compounds with high sensitivity. Obviously ESI is the interface which handles the very polar, partly charged compounds with low as well as high molecular weights in the best way, while the APCl interface can be used successfully for the more lipophilic compounds contained in water samples, e.g. phenol compounds. With the improved flexibility of ESI handhng low and high flow rates of eluents ESI-CEz-MS became a powerful tool to separate complex mixtures with an improved separation efficiency never previously observable with any kind of LC (see Eig. 15.6) [395]. 

Figure 4 Viscosity of the microemulsion phase (made up with the commercial anionic surfactant mixture TRS 10-80, a sulfonate with an approximate molecular weight of 420) as a function of the salinity. (Data taken from Ref 89.)...

When some commercial surfactants exhibited a precipitous drop in and efficiency between 0.5 and 5% water content, as did the nonionic surfactants Triton X-100 or Triton N-101, others behaved in a manner similar to our contrived nonionic-anionic surfactant mixtures. It is thus apparent that accurate calculation of the relative radioactivity of emulsified aqueous samples depends on rigorous uniformity of sample preparations. Optimal proportions of surfactants, surfactant content, and water content will depend on the nature and amount of the solute being counted. The usual methods of quench correction in LSC must be examined very carefully, inasmuch as they will usually not be adequate for determining absolute counting efficiency. 

FIGURE 15.23 Oil recovery percentages obtained with some surfactant systems. The results were determined as a function of injected porous volume for surfactant systems with various concentrations above the CMC. Graphs (a), (b), (c), and (d) refer to different nonionics graphs (e) and (f) correspond to the anionics graph (g) shows the behavior of the cationic surfactant system graph (h) is the result of a nonionic and anionic surfactant mixture. 

Xiao J-X, Zhang Y, Wang C, Zhang J, Wang C-M, Bao Y-X, Zhao Z-G. Adsorption of cationic-anionic surfactant mixtures on activated carbon. Carbon 2005 41(5) 1032-1038. 

The oil mixture consists of dicaprylyl ether and octyl dodecanol in a ratio of3 l. The hydrophilic emulsifier is a 5 3 mixture ofcocoglucoside (APG) and sodium laureth sulfate (SLES). This high-foaming anionic surfactant mixture forms the basis of many body cleansing formulations. The hydrophobic coemulsifier is GMO. The water content is kept constant at 60%. Starting... 

Hatton et al. have also reported on the aggregation of cationic/anionic surfactant mixtures to form vesicles. The systems studied were SOS/CTAB, SDS/DTAB, HDBS/CTAB (DTAB and CTAB = dodecyl and hexadecyl tri-methylammonium bromide SOS = sodium octylsulfate HDBS = dodecylbenzenesulfonic acid). The transition to stable vesicles is rather slow for the SOS/CTAB and SDS/DTAB systems and complex with the observation of three relaxation processes with relaxation times of about 10, 100, and 2000 s in addition to a very fast process (< 4 ms, the dead time of... 

Low degrees of ethoxylation tend to render the surfactant oil soluble, whilst higher levels confer water solubility. The use of non-ionic surfactants may sometimes lead to the formation of small aggregates or grainy emulsions. This tendency is due to the weaker surface activity and the relative difficulty with which non-ionic surfactants form micelles. As a result of these deficiencies non-ionic/anionic surfactant mixtures are normally employed in emulsion polymerisation. The ionic component allows easy solubilising of the monomer whilst the non-ionic component confers emulsion polymer stability. 

The miscibility of anionic surfactant mixtures is affected by electrostatic effects which are absent in nonionic surfactant mixtures. This simplifies the interpretation of their solubility data. Furthermore, the miscibility of nonionic surfactants in micelles can be compared to their mutual solubility in the liquid state. 

Garcfa-Delgado, R. A., L. M. Cotoruelo-Minguez, J. J. Rodrfguez, Adsorption of anionic surfactant mixtures by polymeric resins, Sep. Sci. TechnoL, 1992,27,1065-1076. 

Pinazo, A., X. Domingo, Turbidimetric analysis of amine oxides and amine oxide-anionic surfactant mixtures, J. Am. Oil Chem. Soc., 1996, 73,143-147. 

Takano, S., A. Hasegawa, H. Ohotsuka, Determination of soap in anionic surfactant mixtures and amine and quaternary ammonium salts in cationic surfactant mixtures by using an automated photometric titrator (in Japanese), Bunseki Kagaku, 1988,57(5), 137-141. 

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