Characteristics of Solute Transfer in Sodium Dioleyl Phosphate/Sodium Bis(2-Ethylhexyl) Sulfosuccinate Microemulsion Systems

Abstract

The behavior of solute transfer in sodium dioleylphosphate (SDOLP)/n-heptane and SDOLP-AOT/n-heptane systems was elucidated by focussing on the extraction process in Winsor II and the solute-exchange process between microemulsion droplets. The extraction of tryptophan (Trp) between the organic and aqueous phases is rather fast for the simultaneous extraction of water and Trp in the SDOLP and SDOLP/AOT systems, whereas in the extraction of Trp without water transfer between the microemulsion droplet and the aqueous phase, the rate slows down significantly with the addition of SDOLP in the AOT system. The rate of the interdroplet exchange process is insensitive to the presence of SDOLP. The reason for the difference in these two processes is discussed with the help of a model of the exchange processes.