Abstract
A study was made of the solubilities of NaSCN, Na2CO3, Na2SO4, and urea in mixed solutions of sodium dodecyl-tri(oxyethylene)sulfate (DES) and sodium tetradecenesulfonate (AOS) at a concentration of 20wt %/ Solubility was measured at 25°C by a visual method. A maximum on the solubility vs. mole fraction curve was found at a molar ratio of AOS (1) : DES (2) for Na2CO3 and AOS (1) : DES(1) for NaSCN, but was not observed for Na2SO4 or urea. The maximum solubilities of Na2CO3, and NaSCN corresponded about 87 % and 30 %, respectively, those when using pure water at the solvent at 25°C maximum. Na2CO3 solubility was also observed in mixed surfactnt solutions of DES with other kinds of surfactants. Thus, maximum solubility may be considered to take place when (1) at leass alkylpoly(oxyethyylene)sulfate bil is present at the surfactant in solution, and (2) the hydration of salt dissolved is weaker than that of ionic polar groups (R-SO3- or R-SO4-), but stronger than that of poly(oxyethylene) groups in the surfactant.
