Dodecyl ether sulfate

Recently, patented ethoxylation catalysts have become available that can significantly narrow the ethylene oxide distribution of the alcohol ethoxylates used to obtain alcohol ether sulfates. These products are termed peaked alcohol ether sulfates whereas all others are termed conventional alcohol ether sulfates. Peaked alcohol ether sulfate solutions thicken more than those with a conventional ethylene oxide distribution [78]. Peaked alcohol ether sulfate solutions also exhibit behaviors different from those of conventional sulfates [79]. Smith [78] studied the viscosities of 15% sodium dodecyl ether sulfate solutions of both families with NaCl content between 2% and 10% at 25°C using a Brookfield model DVII viscometer at a shear rate of 2 s 1. The results are shown in Fig. 5 where the very different viscosities achieved are clearly observed. 

FIG. 5 Viscosity of sodium dodecyl ether sulfate vs. wt % of NaCl and average number of moles of ethylene oxide [78]. (Reprinted with permission of American Oil Chemists Society.)... 

TABLE 6 Krafft Temperatures (°C) of Dodecyl Ether Sulfates... 

Fig. 4 Degree of dissociation (a) of dodecyl ether sulfate micelles...

Fig. 5, curve 1, shows - for dodecyl ether sulfates - the areas occupied by a molecule at c as a function of the number, m,of EO groups. The values were calculated by the Gibbs equation from the surface tension measurements. For 0 - m - 2 there is an area increase with increasing m, however, considerably... 

It was concluded from measurements of sedimentation, diffusion, and viscosity, that the hydration of the micelles of the dodecyl ether sulfates at m = 0 - 2 shows only a little increase, whereas a strong one was observed at m > 2. A similar trend should also exist with the distance of the terminal groups on the surface of the micelles. 

Selected Results. No mutual intensification of interfacial effects is observed between Na dodecyl sulfate as the first member of the homologous series of dodecyl ether sulfates and LAS. In Fig. 11, the oil/ water interfacial tensions are shown. Neither the electrostatic nor the van der Waal s interactions of the mixtures are intensified. 

Sodium diethylene glycol dodecyl ether sulfate ... 

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