Taurates

Taurates can also be classed as modified soap, being similar to isethionates in structure and function. Taurates are useful secondary surfactants, used to modify the properties of primary surfactants. 

The chemistry of taurates is analogous to isethionates, with the ester link replaced by an amide. This gives taurate improved stability to temperature and pH compared to the equivalent isethionate. 

The most common derivative, N-methyl cocoyl taurine has limited solubility and is commercially available as a 30% paste. Formulators should be aware that the figure is typically a solid content, with the surfactant content being 25%, the balance of solids being mainly salt. 

Fatty acid chlorides have been discussed in Section 4.4.3. As with isethionates and sar-cosinates, the cocoyl derivative is predominant. 

(2004) Petrochemical based surfactants. Proceedings 6th World Surfactants Congress. 

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

Figure I. Phase equilibria for varying molar ratios of oleic acid, sodium oleate, and monoolein in bile salt and sodium lauryl taurate...

Sodium lauryl taurate was chosen as a prototypic anionic detergent to compare with the bile salt mixture. This detergent possesses a fatty acid chain rather than the hydroxylated cyclopentenophenanthrene... 

The data clearly indicate that the surface pH of the bile salt micelle is higher than the surface pH of a lauryl taurate micelle for a given bulk pH—i.e., the difference between bulk and surface pH is less with the bile salt micelle. The bile salt micelle should have a lower charge density and therefore a lower concentration of protons at the surface of the micelle. Therefore, the observed bulk pH at which micellar fatty acid ionizes is closer to the bulk pKa of molecularly dispersed fatty acid (4.9) in bile salt solution than in lauryl taurate solution. 

Several other anionic surfactants are commercially available, such as sulfosuccinates, isethionates, and taurates, and these are sometimes used for special applications. The carboxylates and sulfates are sometimes modified by the incorporation of a few moles of ethylene oxide (referred to as ether carboxylates and ether sulfates, respectively). 

Chemistry and general properties. Taurine is amino ethane sulphonic acid, and although it is possible to prepare true acyl taurates, superior performance is obtained by using N-methyl taurine (see Figure 4.27). Taurate in this section is used to mean the N-methyl derivative, as is common in industry. 

Kier Boiling Assistants Sodium-N-Methyl Taurate derivatives Cotton, Rayon... 

Fatty ethoxylate polyester Fatty glyceride blend Fatty imidazoline Fatty imidazoline salt Fatty taurates Fluor-carbon resin Fluorochemical... 

Sodium lauryi sulfate Sodium-N-methyl taurate HARTENOL Hart... 

I.N. Mefford, M. Ota, M. Stipetic and W. Singleton, Application of a novel cation-exchange reagent, IGEPON T-77 (V-methyl oleoyl taurate), to microbore separations of alumina extracts of catecholamines from cerebrospinal fluid, plasma, urine and brain tissue with amperometric detection, J. Chromatogr, 420, 241-251 (1987). 

Several other anionic surfactants are commercially available such as sulphosuccinates, isothionates and taurates, and these are sometimes used for special applications... 

U.S. 6013616 (2000) Fabry et al. (Henkel) Monoglyceride (ether) sulfate fatty acid condensations (isethionates, taurates, or sacrosinates) Mild detergent mixtures... 

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