Anion mixture

The direct reaction of 1-alkenes with strong sulfonating agents leads to surface-active anionic mixtures containing both alkenesulfonates and hydroxyalkane sulfonates as major products, together with small amounts of disulfonate components, unreacted material, and miscellaneous minor products (alkanes, branched or internal alkenes, secondary alcohols, sulfonate esters, and sultones). Collectively this final process mixture is called a-olefinsulfonate (AOS). The relative proportions of these components are known to be an important determinant of the physical and chemical properties of the surfactant [2]. 

Fig. 10 Effect of surfactant concentration on the optimum formulation (minimum tension position) for anionic mixtures (/e/t), pure anionic surfactant center) and ethoxylated nonionic mixtures (right)...

Our data, to date, show that molecular interaction between two surfactants, both in mixed monolayers at the aqueous solution/air interface and in mixed micelles in aqueous solution, increases in the order POE nonionic-POE-nonionic < POE nonionic-betaine < betaine-cationic < POE nonionic-ionic (cationic, anionic) betaine-anionic cationic-anionic. The greatest probability of synergism exists, therefore, in cationic-anionic mixtures, followed by betaine-anionic mixtures. Synergism can exist in POE nonionic-ionic mixtures only if the surfactants involved have the proper structures. 

CftNBr-CTFNa (cationic-anionic) system. The common cat ionic-anionic mixture of HC surfactants is highly surface active (17), showing the strong interactions between the two oppositely charged surface active ions. Similar re.-sults have been observed in the case of CeNBr-CrFNa system. The "y-log C plot in Fig.5 illustrates such an interaction, lile can see that the 1i1 CeNBr-C-rFNa mixture is much more surface active than CsNBr or CjFNa, The cmc value of surfactants mixture is much more smaller than that of CaNBr or CyFNa, and the-yeme the mixed solution is very low (< 15 rnNrn- ) mixtures with various raolal... 

Tetrahydrofuran (3.2 ml) and S-(+)-3-chloro-l,2-propanediol (0.299 ml, 3.58 mmol, 1.19 eq) are mixed. The mixture of THF (3.2 ml) and S-(+)-3-chloro-1,2-propanediol (0.299 ml, 3.58 mmol, 1.19 eq) is cooled to -16°C and potassium t-butoxide (3.2 ml, 1.0 M) in THF (3.2 mmol, 1.07 eq) is added at less than -10°C. The resulting slurry is stirred at -14-0°C for 1 hour. Then added to the lithium anion mixture while maintaining both mixtures at 0°C, then rinsed in with THF (2 ml). The resultant slurry is stirred at 20-23°C for 2 hour and then cooled to 6°C and a mixture of citric acid monohydrate (0.4459 g, 2.122 mmol, 0.705 eq) in water (10 ml) is added. The resultant liquid phases are separated and the lower aqueous phase is washed with ethyl acetate (12 ml). The organic layers are combined and solvent is removed under reduced pressure until a net weight of 9.73 g remains. Heptane (10 ml) and water (5 ml) are added and solvent is removed 4-nitrobenzenesulfonyl chloride y reduced pressure until a total volume of 5 ml remains. The precipitated product is collected by vacuum filtration and washed with water (7 ml). The solids are dried in a stream of nitrogen to give (R)-[N-3-(3-fluoro-4-(4-morpholinylphenyl)-2-oxo-5-oxazolidinyl]methanol. 

Most of the element recovery technology has been involved with separating cation mixtures (see, e.g., [93-96]) but separation of anion mixture is also a potential path to this objective, as the following example shows. Consider the case where a solution containing a certain ion to be removed, e.g., in Bi ion recovery from seawater is exposed to a Br" ion-selective exchanger initially in the Cl" form at temperature Tj. The exchange reaction presented below then results in enrichment of Bi" in the... 

Ironically, species such as (89 M Li) are also the major isomers obtained when unsymmetrical ke-timines are deprotonated with LDA at -78 There is a kinetic preference for deprotonation anti to the substituent on nitrogen. At very low temperatures, deprotonations with LDA occur at the less-substituted carbon atom via the less stable (Z)-imine. Rearrangements then occur to the syn, less-substituted imine, which is in turn alkylated. On the other hand, deprotonations conducted at -23 to 0 C with LDA are faster than imine isomerization and the imine anion mixture composition reflects the ( ) (Z) ratio of the starting imine. Anti-syn imine anion isomerization occurs to give predominately the more-substituted fyn-metallated imine (cf. 90), which then undergoes alkylation. These results are summarized in Scheme 46 using the f-butylimine of 2-butanone as an example. 

CHA/CF1E] Chao, E. E., Cheng, K. L., Stepwise titration of some anion mixtures and determination of Kjp of silver precipitates with silver ion selective electrode. Anal. Chem., 48, (1976), 267-271. Cited on pages 303, 544. 

There are considerable differences in the selectivity coefficients of common inorganic anions for anion-exchange resins as shown by the data in Section 3.5. Qassical separations based on these affinity differences have been achieved, although they were often quite slow. However, excellent separations of anion mixtures can be obtained by modern anion chromatography. 

Figure 10.4. Separation of a standard anion mixture. BGE 5 mM molybdate, 0.15 mM CTAH, 5 mM Tris buffer at pH = 7.9, 0.01 % PVA Capillary 65 cm x 0.075 mm i.d. fused silica Run -20 kV Current 12 juA Injection 8 cm for 20 s Detection 230 nm. Anions, 2 ppm each 1 = chloride 2 = sulfate 3 = nitrate 4 = fluoride 5 = formate 6 = phosphate 7 = carbonate 8 = acetate. From Ref [3].

Figures 4 to 6 give experimental c0 vs. tt curves for different single surfactant systems. The 1 1 cationic-anionic mixture effectively behaves as a single surfactant, DTA-DS (8). The tt vs. A curve obtained by...

The discussion above illustrates that various anion column occupants are incompatible as nearest neighbors, at least given the end-member structures. Yet, such solutions do indeed occur solid solution among all three anions is not uncommon. Clearly, structural adjustments must occur to accommodate anion mixtures in the columns for example, without such accommodations. Cl could not coexist in the columns with other anions. The situation is illustrated in Figure 2, which depicts a Cl ordered below a plane at z = V4, and the five possible anion occupants at the adjacent mirror plane at z = V4. As depicted in Figure 2, possible column-anion neighbors... 

Roy, W. R., Hassett, J. J., and Griffin, R. A. (1989). Quasi-thermodjmamic basis of competitive-adsorption coefficients for anionic mixture in soils. 

The most important factor determining the composition of an enolate anion mixture is whether the reaction is under kinetic (rate) control or thermodynamic (equilibrium) control. In a reaction under thermodynamic control,... 

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