Aqueous Solutions of Sodium Oleate

Sodium oleate is best prepared from oleic acid, which is commercially available in a pure state by saponification. Weigh out 28.25 g purest oleic acid, place in a 150 cm beaker and heat on a water bath. Prepare 10% w/v solution of NaOH. Add the solution, slowly and with stirring, to the hot oleic acid until the acid is saponified ( 40 cm will be required). Separate the solid soap formed by filtration under suction. Recrystallise from ethanol. Prepare solutions from the solid using dilute NaOH to keep the pH at 10 to stop hydrolysis. 

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The suitable system for studying linear energy K is the small circular black film (separating two gas phases) in contact with the bulk phase of the solution from which the film is formed. The presence of linear energy of this contact line can be expected on the basis of the experimental observations leading back to Boys [316]. He estimated its values to be less than 5.25-10 4 dyn (positive) for an aqueous solution of sodium oleate and glycerol. 

As described in Example 3.44, a mixture of 10 g (0.19 mol) of acrylonitrile containing 0.1 g dodecylmercaptane as regulator and 25 g (0.46 mol) of butadiene is polymerized in 50 ml of a 5% aqueous solution of sodium oleate (or sodium dodecyl sulfate) containing 0.25 g (0.93 mmol) of potassium peroxodisulfate as initiator. After 18 h the pressure bottle is allowed to cool to room temperature and is finally cooled in ice. It is now weighed again to confirm that no butadiene has been lost by leakage. The bottle is carefully opened, the latex poured into a beaker and... 

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