Enhancement of the Solubilization Capacity of Water in Triton X-100/Cyclohexane/Water System by Compressed Gases

The effect of compressed CO2 and ethylene on the properties of Triton X‐100/cyclohexane/water systems was studied at different temperatures and pressures. Surprisingly, it was discovered that the compressed gases had the functions of co‐surfactants. At suitable pressures, the water‐to‐surfactant molar ratio (W0) was enhanced significantly by the dissolution of the gas in the solution. The microenvironment in the reverse micelles was investigated by UV‐visible spectroscopy by using methyl orange (MO) as a probe. The influence of n‐hexane, Na2CO3, NaHCO3, H2C2O4, and CaCl2 at various concentrations on the solubilization of water in the absence of compressed gases was also investigated in order to obtain some information about the mechanism of the interesting phenomenon. This new route to stabilize reverse micelles may have potential applications to other similar systems. Moreover, the results of this work provide some useful information to get insight into the mechanism of co‐surfactants, because a conventional co‐surfactant usually contains both polar group and hydrocarbon chain, and it is very difficult to clarify the functions these two groups, while the gases used in this work are small nonpolar molecules, which solely have the function of the hydrocarbon chain in a co‐surfactant. Reverse micelle systems: Compressed CO2 and ethylene in Triton X‐100/cyclohexane systems have the functions of co‐surfactants in that they can stabilize reverse micelles by decreasing the attractive interaction between the droplets. The figure illustrates that the amount of solubilized water with (○) compressed CO2 at suitable pressure is much larger than that without (•) the gas (cTX = 0.31 mol L−1).