Influence of Selected Surfactants and High-Octane Oxygen Components on Water Content, Electrolytic Conductivity in Gasoline, and Interfacial Tension in the Water/Gasoline System

Abstract

The influence of selected surfactants and oxygen containing components on solubility of water, electrolytic conductivity in gasoline, and interfacial tension in the water/gasoline system was studied. Anionic sodium bis-(2-ethylhexyl)sulfosuccinate (AOT), the branched alkylamine Primene JM-T, and some hydrophilic additives (alcohols and methyl tert-butyl ether) were examined. Slight amounts of amphiphilic substances can improve the solubility of water, and they may cause the association phenomena with the formation of reverse micelles. Hydrophilic groups of the compounds are located inside the micelles, in which the water pools can be contained. Surfactant aggregates and droplet clusters are contained in the microemulsion solution due to the dipolar interaction between the dispersed droplets. The formation of these structures induces an increase in the solubility of water in gasoline. The improvement of electrolytic conductivity depends on the type and concentration of surfactants and hydrophilic additives. Conductivity is very sensitive to microemulsion structure and it significantly increases because of the presence of reverse micelles, which are able to transport charges. Correlation between conductivity, water content, and interfacial tension has been analyzed. On the basis of the calculated coefficients, the closest correlation between these parameters was osberved in the case of the addition of AOT and hydrophilic components.