关键词: 增溶, 电解质, 丙酸十二铵, 四氯化碳, 非水溶液, 反胶束

Abstract:

The limiting solubilization amount of aqueous solution of electrolytes, including NaCl, KCl, NaBr, NaI, CaCl2 and Na2SO4 in carbon tetrachloride solution of dodecylammonium propoinate was determined as the added amount of aqueous solution at which turbidity began to be visible. All of the results showed that with increasing concentration of electrolytes, the limiting solubilization amount of aqueous electrolyte solution increased first followed by decreased. This phenomenon could be explained as follows. When electrolyte was present in water pool of reverse micelle, it makes easier for surfactant molecules that surrounding the water pool to migrate to organic phase because of salting-out effect, thus the reverse micelle was expanded. This effect increased with increase of electrolyte concentration. On the other hand, surfactant molecules migrating easier to organic phase implies that the force making surfactant molecules to stick on the surface of water pool became weaker. When electrolyte concentration increased to a certain extent, this force became too weak to keep the reverse micelle, thus the limiting solubilization amount of aqueous solution decreased. According to simplified spherical reverse micelle model, the aggregation number as well as the radii of water pool of reverse micelle have been calculated for aqueous sodium chloride solution of different concentrations. The results support the above explanation.

Key words: Solubilization, Electrolytes, Dodecylammonium propionate, Carbon tetrachloride, Nonaqueous solution, Reverse micelle