Alkylsulfate anion

The most common anions are CT, Br, [BFJ, and [PFJ. For simplicity, trifluoromethanesulfonyl [CF3S02] anion is abbreviated as [TfO], l7/s(trifluo romethanesulfonyl)imide [(CF3S02)2N] anion as [Tf2N] (Tf is a short-hand notation for triflate), and dicyanamide [N(CN)2]" anion as [dca]. There are several examples of alkylsulfate anions, which we will abbreviate [C SOJ , where n is the carbon number of alkyl chain. 

Canongia Lopes, J.N., Padua, A.A.H. and Shimizu, K., Molecular force field for ionic liquids IV Trialkylimidazolium and alkoxycarbonyl-imidazolium cations alkylsulfonate and alkylsulfate anions, J. Phys. Chem. B 112, 5039-5046 (2008). 

Anion effect was also evaluated employing the same cation ([BMIM]) working at the same experimental conditions. The alkylsulfate anions shows the best extractive properties between the neutral ILs. On the other hand, the effect of the N-alkyl chain also play an important role in the performance of these compeunds, increasing the extractive properties from n-C2 to n-C8. 

The most commonly used emulsifiers are sodium, potassium, or ammonium salts of oleic acid, stearic acid, or rosin acids, or disproportionate rosin acids, either singly or in mixture. An aLkylsulfate or aLkylarenesulfonate can also be used or be present as a stabilizer. A useful stabilizer of this class is the condensation product of formaldehyde with the sodium salt of P-naphthalenesulfonic acid. AH these primary emulsifiers and stabilizers are anionic and on adsorption they confer a negative charge to the polymer particles. Latices stabilized with cationic or nonionic surfactants have been developed for special apphcations. Despite the high concentration of emulsifiers in most synthetic latices, only a small proportion is present in the aqueous phase nearly all of it is adsorbed on the polymer particles. 

Anionic surfactants are the most commonly used class of surfactant. Anionic surfactants include sulfates such as sodium alkylsulfate and the homologous ethoxylated versions and sulfonates, eg, sodium alkylglycerol ether sulfonate and sodium cocoyl isethionate. Nonionic surfactants are commonly used at low levels ( 1 2%) to reduce soap scum formation of the product, especially in hard water. These nonionic surfactants are usually ethoxylated fatty materials, such as H0CH2CH20(CH2CH20) R. These are commonly based on triglycerides or fatty alcohols. Amphoteric surfactants, such as cocamidopropyl betaine and cocoamphoacetate, are more recent surfactants in the bar soap area and are typically used at low levels (<2%) as secondary surfactants. These materials can have a dramatic impact on both the lathering and mildness of products (26). 

Anionic Alkylbenzene sulfonates, alkylsulfates and ethoxysulfates, sulfosuccinates, phosphate esters, taurates, alkylnapthalene sulfonates, lignosulfonates... 

Halogen content If halogens in the anion are not crucial for specific reactions performed in the ionic liquid, they should be avoided. Moisture sensitivity, halogenide transfers, alcoholysis and toxic effects are often connected with halogen atoms in the molecule [27]. In addition, the hydrolysis products HCl or HF act corrosively. Within the project reported by Wasserscheid and coworkers they successfully developed ionic liquids with alkylsulfate groups as anions to overcome the halogen content. These new solvents show very favorable properties. 

ILs based on the l-alkyl-3-methyIimidazoIium cation, [C CiIm] , or tetra-alkylammonium cation, [(C )4N]l are among the most popular and commonly studied or used in technological improvements. As for the anions, l7is(trifluoromethylsulfonyl)imide, [Tf2N], and alkylsulfate, [C S04] (n = 1, ll 8), are much superior compared to the more commonly investigated hexafluorophosphate, [PFg] , and tetrafluoroborate, [BF4], being hydrolytically stable and less viscous. Comparing the results of the solubility of ILs in typical solvents from different publications, it can be concluded that the miscibility gap in the liquid phase increases in the order alcohol < aromatic hydrocarbon < cycloalkane < n-alkane [50-54,66,78,79,95-100,127-136]. 

It seems likely that the cationic CPC micelles, which have a large positive charge at or near the micellar surface, interact attractively with the n-molecular orbital system of benzene, and that this interaction contributes to the fact that the solubilization constant for benzene in CPC is approximately twice as large as that in SDS micelles. A preferential interaction between cationic surfactants and aromatic solutes has been reported by several groups of investigators (25-27), and recent work in our laboratory shows that 1-hexadecyltrimethylammonium bromide micelles also solubilize benzene more effectively than do the anionic alkylsulfate surfactant micelles (28). Thus, the tendency of benzene molecules to solubilize near the surface of the cationic micelles, at low XB values, may lead to a partial saturation of surface "sites" by benzene, diminishing the ability of additional benzene molecules to bind near the surface. Such an effect could be responsible for the initial increase in activity coefficient that occurs, particularly in the CPC solutions, as Xg increases. 

For anionic surfactants colorimetric methods utilize the formation of an ion pair between the surfactant anion and a cationic dye. Similarly to two-phase titration, colorimetric determination is based on the fact that the ion pair is extractable into organic solvent, while the dye by itself is not. A characteristic example of the analysis of anionic surfactant is the determination of alkylsulfates and alkyl(aryl)sulfonates as their complex with methylene blue extracted into chloroform [31]. The absorbance of chloroform extract is measured at 625 nm versus chloroform background. This methods allows one to analyze alkylsulfates and alkyl(aryl)sulfonates separately. Alkylsulfates, in contrast to sulfonates, are easily hydrolyzed by hydrochloric acid. The products of hydrolysis do not interact with methylene blue and are not transferred into chloroform. Some other cationic dyes, such as dimidium bromide, can also be used. In fact, the use of the latter allows one to achieve much higher sensitivity than that obtained with methylene blue. 

The described mechanisms of detergency are put into practice by using synthetic micelle-forming surfactants, among which the mixtures of anionic and nonionic surfactants (particularly alkylsulfates and oxyethylenated alcohols) make 10 to 40 % of the total detergent formulation. Cationic surfactants (alkylamines) that are also included into synthetic detergent formulations may contribute up to 5% of the total amount of formulation. These substances reveal biocidal action and control micelle formation by forming mixed micelles. 

Other nonhalogenated anions, such as tosylate, sulfate, alkylsulfate, sulfonate, borate, lactate, or salicylate, have been developed more recently and their physicochemical properties have been described. ILs with triazolate anions can serve as both solvent and basic catalyst for the isomerization of isocyanate [15]. 

The mesomorphism of silver(I) complexes of poly(alkoxy)stilbazoles has been reviewed recendy. However, it is appropriate to cover this work here in order to see the effect of an anion on mesomorphism in cationic complexes and to allow some comparison to be made with the complexes described in the preceding section. In these studies, there were two main variables, namely the substitution pattern of the stilbazole used and the nature of the anion. The former was varied in the same way as for the palladium and platinum complexes just described, while the latter was either triflate or an alkylsulfate whose chain length was varied. 

The transition temperatures of these complexes were, however, signifieantly reduced when the small anions used above were replaced by alkylsulfates (dodecylsulfate DOS octylsulfate—OS ) ... 

Domagk, " as early as 1935, soon after the introduction of the cationic disinfectants, noted their inactivation by soap and other anionic detergents (Figure 2). The inhibition of the synthetic cationic detergents by anionic compounds, including phospholipids and alkylsulfates, was studied, using microbiological techniques. 

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