Octylsulphate

Lyklema and Mysels [168] have studied equilibrium macroscopic vertical foam films from sodium octylsulphate aqueous solution containing KC1. The film thicknesses comprised a large range from 80 to 8 nm and electrolyte concentrations from 103 to 1 mol dm3 (Fig. 3.18). 

Figure 21 Molecular stracture of the methoxystilbazole complex of silver octylsulphate.

In another sulphation study the kinetics of the reaction of sulphamic acid with 2-octanol to give sec-octylsulphate were found to be first order in sulphamic acid with energies and entropies of activation of 3.1 + 0.6 kcal mol-1 and 15 2 e.u. (in DMF) and 33.7 + 1.0 kcal mol -1 and 17 + 3 e.u. (in dimethyl sulphoxide)64. In dimethylformamide the mechanism involves the slow formation of DMF SO 3 followed by its rapid reaction with the alcohol to give R0S020NH4. 

Fig. 13.3 Separation of UV-inactive anionic and cationic compounds. (Reproduced by permission of Elsevier Science Publishers BV from M. Denkert etal., J. Chromatogr., 218, 31 (1981).) Anions detected before the system peak produce positive peaks and cations produce negative peaks, whereas the reverse applies for compounds following the system peak. Conditions column, 10 cm x 3.2 mm i.d. stationary phase, riBondapak Phenyl, 10rim mobile phase, 0.5 ml min 4x 10 " M naphthalene-2-sulphonate in 0.05M phosphoric acid UV detector, 254nm. Peaks 1 = butylsulphate 2 = pentylamine 3 = hexanesulphonate 4 = heptylamine 5 = octanesulphonate 6 = octylsulphate S = system peak.

Copper and brass (CuZn40) are among the various materials used by Uerdingen et al. in their work [6]. Some imidazolium derivatives with different substituents and varying anions (ethylsulphate, octylsulphate, tosylate, chloride and dimethyl-phosphate) and a pair of quaternary ammonium with methylsulphate or saccharinate as anions were used. In water-free ILs experiments, copper and brass showed to be particularly sensitive to the presence of tosylate anion, with corrosion rates between 15 and 25 mm year at 90 °C whereas ethylsulphate produced corrosion rates in the order of 2 mm year . Addition of a 10 % of water approximately doubles the corrosion rate. 

Aluminium is considered to be a very suitable material for the cathodic current collector in lithium-ion batteries, but it may corrode in contact with the electrolytes used in that kind of devices. The use of ionic liquids as corrosion inhibitors of aluminium and aluminium alloys was pointed out by Uerdingen et al. [6] when an Al- alloy (AlMg3) showed a very low corrosion rate (0.03 mm-year ) in the presence of different imidazolium derivatives with different and varying anions (ethylsulphate, octylsulphate, tosylate and dimethylphosphate), especially in the absence of water. Adding 10 % of water, mass loss values were under 0.1 mm-year. ... 

Barium octylsulphate (BaOS) is virtually insoluble in water and does not form any liquid crystalline phase with water between 298 and 323 K. Addition of decanol to the aqueous system leads to the formation of the lamellar liquid crystalline phase, yet incompletely characterized. However, it appears that the lamellar phase exists at low water contents and probably occupies a small area in the phase diagram. The phase diagrams of the barium surfactant systems are compared with those of the corresponding systems with and Ca + counterions and the results are discussed in the light of electrostatic theory. 

Key words Barium di-2-ethylhexylsulphosuccinate, barium octylsulphate, liquid crystals, phase diagram, NMR... 

The studies reported so far on the surfactant systems with divalent counterions are very few and limited to calcium and magnesium. Here we present the binary phase diagram (composition vs temperature) of the system barium di-2-ethylhexyIsulphosucdnate (BaA2)- iO. We will also make a preliminary report on the isothermal ternary system of barium octylsulphate (BaOS)-decanol- /). 

A concentrated solution of BaAj or BaOS in methanol did not show the presence of Na when Na NMR was run with a few thousand pulses whereas a sharp peak on the Na NMR spectrum was observed with a few pulses for a corresponding solution containing NaA or sodium octylsulphate. 

In the ternary alkaline earth octylsulphate-decanol-water system, the extension of the lamellar liquid crystalline phase towards the water comer increases in the order Mg " > Ca + > Ba (28 moles 0 per mole surfactant ion for magnesium against 18 moles for the calcium system and not quantified for the barium system). On the other hand, the minimum amount of water necessary to form the lamellar liquid crystalline phase in the calcium and magnesium systems is approximately the same, 8 moles per mole surfactant ion [4],... 

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