A SuLFOPALMITIC ACID

The solubility of several salts of alkyl esters of a-sulfopalmitic acid and a-sulfostearic acid was measured by Stirton et al. [30]. The aqueous solubility of the a-sulfopalmitates is better than the solubility of the a-sulfostearates and it also increases with increasing molecular weight of the alcohol. The same dependency is found in organic solvents, such as chloroform ethanol, petroleum ether diethyl ether, and mineral oil. They also showed that esters of secondary and branched chain alcohols are more soluble than esters of normal primary alcohols. 

The oldest report we know dealing with the polymerization of a molecule nowadays termed a surfmer is the work of Bistline et al. [31]. They obtained surface-active polymers with a mean degree of polymerization of about 10 by polymerization of allylic esters of sodium salts of a-sulfostearic acid and a-sulfopalmitic acid. 

By detailed study, the above methods can be made more selective for individual surfactants. For example, while the p-toluidine salts of most anionics can be extracted into ethyl ether, that of the methyl ester of a-sulfopalmitic acid cannot, but instead forms a precipitate in the aqueous phase. This can be quantitatively removed by filtration (32). Sulfosuccinic acid diesters can generally be determined by the p-toluidine method, but many sulfosuccinic acid monoesters cannot, because of their lack of solubility in organic solvents (35). 

Besides these normal technical products, many other different types of a-sulfo fatty acid esters have been described in the literature. For example, Weil et al. prepared a-sulfopalmitates and stearates with higher alcohols [19] and also monoesters of polyhydric alcohol [39] and of hexitols and sucrose [40] for their special properties. In addition to the sodium salt, Stirton et al. used other cations, such as Li, NH4, K, Mg, and Ca, to study the relationship between the structure and the surfactant properties [30]. 

The ability to disperse the calcium soap formed from a given amount of sodium oleate has been studied for a number of a-sulfo fatty acid esters with 14-22 carbon atoms [28,30]. In principle, the lime soap dispersion property increases with the number of C atoms and the dissymmetry of the molecule. Esters with 14 C atoms have no dispersion power and in the case of esters with 15-17 carbon atoms the least symmetrical are the better lime soap-dispersing agents. However this property does not only depend on the symmetry but on the chain length of the fatty acid group. For example, methyl and ethyl a-sulfomyristate have better dispersing power than dodecyl propionate and butyrate. The esters with 18 and more carbon atoms are about equal in lime soap dispersion power. Isobutyl a-sulfopalmitate is the most effective agent under the test conditions. 

A heavy granular detergent can be produced by mixing a detergent composition with powdered or granular sodium carbonate. A typical detergent comprises 8% sodium a-sulfo hardened palm oil fatty acid methyl ester, 2% di-Na a-sulfopalmitate, 10% Na coconut oil alcohol sulfate, 2% polyethylene... 

Polymer films can be made antistatic with a-sulfonated fatty acid salts and esters [94]. For example, an antistatic additive for polypropylene manufacture can be prepared from potassium methyl a-sulfopalmitate, styrene oligomer, and 2-propanol [95]. The treatment of synthetic fibers and fabrics with a-sulfo-... 

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