SOLUBILITIES OF ETHANE IN AQUEOUS-SOLUTIONS OF SODIUM DODECYL-SULFATEAT ELEVATED PRESSURES

The solubilities of ethane in aqueous solutions of sodium dodecyl sulf ate (SDS) were measured at 313.15 K and at pressures up to 3 MPa. The molalities of SDS (m(SDS)) in the aqueous solution were 0.0000, 0.0020 , 0.0040, 0.0060, 0.0070, 0.0080, 0.0090, 0.0100, 0.0126, 0.0150, 0.02 00, and 0.0300. The effect of SDS on the gas solubility in both concen tration regions below and above the critical micelle concentration (cm c) was studied. The existence of the micelles of SDS in the solution i s favorable to the dissolution of ethane due to the hydrocarbon-like i nterior of the micelles. The solubilities of ethane in each micelle at different pressures were evaluated based on some assumptions. It was found that the intramicellar solubility of ethane is less than that of the gas in n-dodecane. It was also found that the solubility of ethan e in the micelles increases linearly with the partial pressure of etha ne. The cmc of SDS was evaluated based on the solubility vs mss curves and the effect of dissolved ethane on the cmc was studied. It was obs erved that the cmc shifts toward a higher value with the increase in d issolved ethane. (C) 1995 Academic Press, Inc.