Abstract
Thermal change of equilibrium water content of polyoxyethylene series, non-ionic surfactants, toward benzene solution was studied by the double layer method at both 10° and 40° to compare them with that at 25°. The equilibrium water content of certain surfactants was similarly observed to be in a linear relation between the concentrations of surfactants and the water content in benzene layer at a certain temperature. Therefore in the similar series of surfactants, as the average molar number of ethylene oxide was larger, that is, as the HLB value was higher, the equilibrium water content showed a tendency to become larger. When an influence of temperature upon the equilibrium water content was considered, the latter increased as the temperature rose. However, the solubilization of water per mole of ethylene oxide residue was not influenced by the thermal changes. One mole of water was solubilized by about 10 moles of ethylene oxide and an increase of the equilibrium water content was explained bythe increase of the solubility of water into benzene.
