Tetradecyldimethylammonium linoleate

Micellar and pre-micellar solutions of methanol in triolein were studied with three different surfactant systems using 2-octanol as a co-surfactant. Surfactants evaluated by viscosity, conductivity, density, refractive index and particle size data along with polarizing microscopic examinations were bis(2-ethylhexyl) sodium sulfosuccinate, triethylammonium linoleate and tetradecyldimethylammonium linoleate. Data show phase equilibria regions of liquid crystalline phases as well as micellar solutions. All systems were effective for solubilizing methanol in triolein. The order of effectiveness for water tolerance is Tetradecyldimethylammonium linoleate>... 

The bis(2-ethylhexyl) sodium sulfosuccinate system was initially investigated because its structure of liquid crystalline solution phases and mechanism of solubilization with water had been reported by Rogers and Winsor (10). In our studies, we substituted methanol for water. Table I lists critical micelle concentrations for bis(2-ethylhexyl) sodium sulfosuccinate, triethylammonium linoleate and tetradecyldimethylammonium linoleate in methanol and 2-octanol at 25°C. Literature references for critical micelle concentrations in methanol are sparse, and it has even been suggested that in polar solvents such as ethanol, either micellization does not occur or, if it does, only to a small degree (4). The data of Table I show that micellization occurs in methanol at low concentrations. 

Figures 7, 8 and 9 are plots at 25 C of specific conductance and density versus volume fraction of methanol in 2/1 triolein/ surfactant systems which are 4/1 molar ratios of 2-octanol to bis(2-ethylhexyl) sodium sulfosuccinate, triethylammonium linoleate and tetradecyldimethylammonium linoleate, respectively. For each surfactant system, a maximum for specific conductance and a minimum for density was observed at the same volume fraction, but this volume fraction of methanol varied between the three surfactant systems. At volume fractions of methanol above these abrupt changes, each system exhibited translucence, and it appears that gel-like structures form. These data are consistent for microemulsion structures that are based largely on geometric considerations (16-18).

Figure 10 is a ternary diagram for the systems Triolein/S/ Methanol, where S is respectively 4/1 molar ratios of 2-octanol to bis(2-ethylhexyl) sodium sulfosuccinate, triethylammonium linoleate or tetradecyldimethyl ammonium linoleate at 25°C. Not much difference is noted between phase areas for the triethylammonium linoleate and bis(2-ethylhexyl) sodium sulfosuccinate systems. Both are definitely inferior to the tetradecyldimethylammonium linoleate which shows the greatest solubilized area of methanol in triolein at 25°C. 

Plots at 298°K of specific conductance and density against volume fraction of methanol in a 2/1 triolein/ surfactant system which is a 4/1 molar ratio of 2-octanol to tetradecyldimethylammonium linoleate. 

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