Alkylsulfate

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). 

Sodium n-alkylsulfates. Crystd from EtOH/MeaCO [Hashimoto and Thomas J Am Chem Soc 107 4655 7955]. 

ISO 894 1977, Surface active agents Technical sodium primary alkylsulfates—... 

Figure 6 Lipase PS-catalyzed acylation in hydrophobic alkylsulfate IE.

Since aggregates elute more rapidly than free solute, the chromatographic front is not in equilibrium with the surrounding medium but continually undergoes further dissociation, as pointed out by Coll (15) and Tokiwa et al. (12). Working with aqueous alkylsulfate solutions, these authors found that this effect led... 

These systems have been successfully applied as catalyst media for the biphasic, Rh-catalysed hydroformylation of 1-octene [11], [62]. The catalyst activities obtained with these systems were in all cases equal or even higher than those with the commonly used [BMIM][PF6]. Table 7.4 compares some typical results using Rh-sulfoxantphos in alkylsulfate and sulfonate ionic liquids with analogous experiments in a hexafluorophosphate system. 

The ionic liquid investment could be further reduced if future research enables the application of ammonium based alkylsulfate or arylsulfonate ionic liquids. For these systems bulk prices around 15 /kg are expected. Ammonium based alkylsulfate or arylsulfonate ionic liquids usually show melting points slightly above room temperature but clearly below the operating temperature of the hydroformylation reaction. Therefore these systems may be less suitable for the liquid-liquid biphasic process in which the ionic liquid may be involved in process steps at ambient temperature (e.g. phase separation or liquid storage). In contrast, for the SILP catalyst a room temperature ionic liquid is not necessarily required as long as the film becomes a liquid under the reaction conditions. Assuming an ammonium based SILP catalyst, the capital investment for the ionic liquid for the industrial SILP catalyst would add up to 105,000 . 

In recent times, the development of new ionic liquids has made great progress. Important developments include a range of new halogen-free ionic liquids (e.g., benzenesulfonates [13], toluenesulfonates, alkylsulfates [14], hydro-gensulfate [15, 16], dicyanamides [17], thiocyanates [18], etc.), as well as functionalized (task-specific) [19-23], fluorinated [24], deuterated [25] and chiral ionic liquids [26-30]. 

In this AES blend, C12 and C14 alkyl chains of alcohols were coupled with polyglycolether chains, which vary in the number of polyether units resulting in homologue [M — H] ions. The ions observed started at m/z 309 (C12-EO1) and 337 (C14-EO1) differing by A m/z 44 (-CH2-CH2—O—) as listed in Table 2.5.1. Here, the ions observable were characterised indicating the number of alkyl and polyether chain links. In parallel, the precursor compounds from synthesis, the alkylsulfates (x = 0), were still present and can be observed with ions at m/z 265 and 293. 

In Fig. 2.5.10(d), under ESI—FIA—MS(—) conditions a discrimination of polyethoxylated AES molecules became obvious. So only the precursor alkylsulfates with ions at m/z 265, 279 or 293 together with the mono-ethoxylated Ci2 and Ci3 and the bis-ethoxylated Ci2 AES presenting the [M — H] ions at m/z 309 and 323 besides 353, respectively, were observable. 

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

The RP-Cis LC separation of this mixture of aliphatic linear alkane sulfonates (CnH2n+i—SO3) and SAS from an industrial blend in combination with APCI—LC—MS(—) detection is presented as total ion mass trace (Fig. 2.11.2(f)) together with selected mass traces (m/z 277, 291, 305 and 319 for (re +x = 11-14)) in Fig. 2.11.2(b)-(e), respectively. The resolved mass traces proved the presence of large number of isomers of every SAS homologue in this blend. This complexity is generated because of the linear isomer precursor and the mixture of branched alkyl precursor compounds applied to chemical synthesis [22], In parallel to elution behaviour observed in GC the branched isomers of alkylsulfates in LC separation were expected to elute first. 

Scheme 3.1 Enzymatic hydrolysis of alkylsulfate esters catalysed by alkylsulfatases proceeding through retention or inversion of configuration...

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. 

Fig. 48. Plots of the rttentioii factor of adrenaline vs the hetaeron concentration for various n-alkylsulfates. Column, Partisil ODS flowrate, 2.0 ml/min temp. 40 failet pressure, 400 psi eluent O.QS AT phosphate in water, pH 2.55, containing various concentrations of the hetaeron. Reprinted with permission from HorvAth et at. (207), Anat. Chem. Copyright (S) 1977 by the American Chemical Society.

Reversed-phase ion-pair chromatography is primarily used for the separation of mixtures of ionic and ionizable compounds. In this chromatographic mode, a pairing ion is added to the mobile phase in order to modulate the retention of the ionic solutes. The pairing ion is an organic ion such as alkylsulfonate, alkylsulfate, alkylamine, tetraalkylammonium ion, etc. Here, only a very brief description of the main ideas behind the electrostatic model for ion-pair chromatography is presented. For a complete discussion, the reader is referred to Ref. [7,8] and the references therein. 

Scamehorn et al (1,2) have studied the influence of adsorption of isomerically pure surfactants and their mixtures on the occurrence of adsorption maxima. We have investigated, therefore, the flotability of barite in solutions of pure Na-alkylsulfates (C, nd... 

Figure 7. Flotation recovery R (in %) of barite as dependent on the concentration c (in mol/L) of Ci2 alkylsulfate-Na mixtures.

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]. 

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. 

Couch, D.B., Forbes, N.L., and Hsie, A.W. (1978). Comparative mutagenicity of alkylsulfate and alkylsulfonate derivatives in Chinese hamster ovary cells, Mutat. Res., 57,217. 

---