Surfactants anionic and cationic

The method developed by Epton [212,213] became the universally accepted method for the analysis of active matter of anionic and cationic surfactants. Epton s method, also known as the two-phase titration, is based on the titration of the anionic surfactant with cetylpyridinium bromide, a cationic surfactant, in the presence of methylene blue as indicator. A solution of the anionic surfactant is mixed with the indicator dissolved in dilute sulfuric acid, followed by further addition of chloroform, and then it is titrated with the cationic surfactant. Methylene blue forms a complex with the anionic salt that is soluble in chloroform, giving the layer a blue color. As the titration proceeds there is a slow transference of color to the water layer until the equivalence point. At the equivalence point colors of the chloroform and water layers are visually the same. On successive additions of titrant the chloroform layer lightens in shade and finally becomes colorless. 

Before use, condition the new electrode by employing it in the titration of a sodium lauryl sulfate solution with a solution of Hyamine 1622 or benzetho-nium chloride solution, 0.04 M using a silver-silver chloride reference electrode. During this conditioning, a layer of an insoluble cation-anion complex becomes firmly attached to the plasticized PVC coating rendering it sensitive to both anionic and cationic surfactants. 

Nearly all nonionic surfactants contain the same type of hydrophobes as do anionic and cationic surfactants, with solubilisation and surfactant properties arising from the addition of ethylene oxide to give a product having the general formula 9.40. Usually, depending on the... 

Anionic and cationic surfactants are more effective in membrane solubilization than nonionic surfactants. 

Even if this class covers the smallest market segment, amphoteric surfactants still remain useful because of their unique properties, which justifies their comparably high manufacturing costs. Since they have partial anionic and cationic character, they can be compatible, under specific conditions, with both anionic and cationic surfactants. They can function in acid or basic pH systems and, at their isoelectric point, they exhibit special behaviour. Many amphoteric surfactants demonstrate exceptional foaming and detergency properties combined with antistatic effects. 

These observations obtained from the application of different API techniques are determinative for qualitative and quantitative FIA results in the analysis of non-ionic and ionic surfactants. Therefore, both ionic surfactant types, anionic and cationic surfactant blends, besides a non-ionic AE surfactant blend were examined, recording their FIA-MS and MS-MS spectra from the blends before the spectra were generated from the mixture of all blends. The results, which show considerable variation, will be presented and discussed as follows. 

Surfactant markers were analysed by Chalaux et al. in marine sediments and sewage sludges [30] from California. The compounds investigated included APEO metabolites A9PEO1, A9PE02 and NP, as well as linear alkylbenzenes (LAB) and trialkylamines (TAM), which are residues of anionic and cationic surfactants, respectively. Sediment cores were collected up to 60 km offshore. 

Experiments with various species simultaneously carried out in ponds, streams or mesocosms have been reported for non-ionic, anionic and cationic surfactants. NP bioconcentration has been studied in the shrimp Crangon crangon, the mussel M. edulis and the fish... 

It is also noteworthy that the surface tension of mixed solutions of anionic and cationic surfactants is controlled by the activity of the salt (38). These results indicate that, in adsorption of an ionic surfactant at the solution surface, the accompanying adsorption of the counter ion also plays an important role. 

Wang, L.K. Neutrahzation effect of anionic and cationic surfactants. J. New Engl. Water Works Assoc. 1976, 90 (4), 354-359. 

A moderately water-soluble complex of anionic and cationic surfactants (1 to 10%), in which the complex (the anionic and cationic moieties) are in essentially equivalent or equimolar proportions, an anionic detergent,... 

When anionic and cationic surfactants are mixed they strongly interact, and it could even be said that they almost react to produce a catanionic species, which is essentially a new surfactant, in which the two hydrophilic groups have merged into a nonionic or a somehow amphoteric head attached to a double tail. The first consequence is that the new daughter species has... 

The phase behavior of anionic-cationic surfactant mixture/alcohol/oil/ water systems exhibit a similar effect. First of all, it should be mentioned that because of the low solubility of the catanionic compound, it tends to precipitate in absence of co-surfactant, such as a short alcohol. When a small amount of cationic surfactant is added to a SOW system containing an anionic surfactant and alcohol (A), three-phase behavior is exhibited at the proper formulation, and the effect of the added cationic surfactant may be deduced from the variation of the optimum salinity (S ) for three-phase behavior as in Figs. 5-6 plots. Figure 16 (left) shows that when some cationic surfactant is added to a SOWA system containing mostly an anionic surfactant, the value of In S decreases strongly, which is an indication of a reduction in hydrophilicity of the surfactant mixture. The same happens when a small amount of anionic surfactant is added to a SOWA system containing mostly a cationic surfactant. As seen in Fig. 16 (left), the values of In S at which the parent anionic and cationic surfactant systems exhibit three-phase behavior are quite high, which means that both base surfactants, e.g., dodecyl sulfate... 

Bourrel M, Bernard D, Graciaa A (1984) Properties of binary mixtures of anionic and cationic surfactants Micellization and Microemulsions. Tenside Deterg 21 311-318... 

Liquid-liquid extraction is used extensively and successfully (6). If the analytes are acidic or basic, as is often the case when HPLC is the analytical method selected, appropriate ionization suppression can be employed to affect the desired extraction. Back extraction of the analytes into an appropriately buffered aqueous volume can then serve to isolate and concentrate. Anionic and cationic surfactants, or so-called ion-pairing reagents, can be added prior to extraction to increase the partition coefficients of the trace organic ionic compounds. 

The information includes location of double bonds In fatty acids, indentlficatlon of components in complex lipids, determination of compositions of anionic and cationic surfactants, and identification of long-chained alkyl substituents on phosphonium and ammonium ions. 

System 1. Under ideal conditions the adsorption of a surfactant into the EDL proceeds as described in Chap. 3. The border of efficiency of anionic and cationic surfactants is IP or PZC, as follows from the correlation of e.g. adsorption density, potential and notability are dependent on pH [e.g. 44,129,167,174-176]. The course of such an adsorption is shown in Fig. 15. If H+ or OH" react with the surface of one mineral the released ions or their hydrolytic products can adsorb on unequally charged surface of the other mineral and cause an activated adsorption of the surfactant, or they can inhibit the adsorption, as shown on the schemes ... 

McAvoy, D.C., White, C.E., Moore, B.L. and Rappaport, R.A. (1994) chemical fate and transport in a domestic septic system Sorption and transport of anionic and cationic surfactants. Environ. Toxicol. Chem., 13(2), 213-21. 

Nonionic surfactants consist of a -(CH2CH20)n0H or -OH as the hydrophilic group and exhibit a variety of hydrophile-lipophile balances (HLB) which stabilize O/W or W/O emulsions. Unlike anionic and cationic surfactants, nonionic surfactants are useful for oral and parenteral formulations because of their low irritation and toxicity. Based on their neutral nature, they are much less sensitive to changes in the pH of the medium and the presence of electrolytes. The best use of nonionic surfactants is to produce an equally balanced HLB of two nonionic surfactants one... 

Agents that decrease the viscoelasticity of mucus, for example anionic and cationic surfactants and bile salts, have been shown to increase absorption. 

Boyer et al. reported [14] on the comparison of performances of anionic and cationic surfactants on inducing reduction of ketones by NaBH4 in two-phase water-heptane systems. Although cationic surfactants are more efficient, the surfactants of either charge type exhibit discernible catalytic effect. This prompted the authors to propose the role of surfactants as promoters of the transfer of lipophilic reactants from heptane to the aqueous phase. 

Fig. 8.7 ICE values during the electrolysis at a BDD electrode of anionic and cationic surfactant solution. Electrolyte 0.0615 mM sodium dodecylbenzenesulfonate solution 0.07 mM hexade-cyltrimethyl ammonium chloride solution, i = 4mAcm 2 (Lissens et al. 2003)...

Various authors have shown that non-ionic surfactants have a beneficial effect on the hydrolysis of cellulosic and lignocellulosic substrates, whereas anionic and cationic surfactants alone interfere negatively (Castanon and Wilke, 1981 Helle et al, 1993 Park et al, 1992 Ooshima et al., 1986 Traore and Buschle-Diller, 1999 Ueda el al., 1994 Eriksson el al., 2002). Increases in the amount of reducing soluble sugars and substrate conversion were reported. The effect depends on the substrate and is not observed for soluble substrates, such as carboxymethylcellulose or cellobiose. Nonionic surfactants increased the initial rate of hydrolysis of Sigmacell 100, and when they were added later in the process they were less effective (Helle et al, 1993). They same authors found also that the addition of cellulose increases the critical micelle concentration of the surfactant, which indicates that the surfactant adsorbs to the substrate. Surfactants are more effective at lower enzyme loads and reduce the amount of adsorbed protein (Castanon and Wilke, 1981 Ooshima et al, 1986 Helle et al, 1993 Eriksson et al., 2002) which can be used to increase desorption of cellulase from the cellulosic substrate (Otter et al., 1989). Anyhow, the use of surfactants to enhance desorption of cellulases from textile substrates in order to recover and recycle cellulases was not successful (Azevedo et al., 2002b). 

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