Abstract:The microemulsion using nonyl hydroxybenzene polyethoxylate ether (TX-10) and cetyl trimethyl ammonium bromide (CTAB) as surfactants, alkanol compounds (such as n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol and n-octyl alcohol) as a co-surfactant and petroleum ether as oil phase was developed. The phase behavior of the microemulsion was investigated. The standard Gibbs free energy change of transfer of alkanol from oil to interface (ΔGθo→i) was determined by dilution method and particle size and surface tension were measured. The interactions between alkanols with different lengths and surfactants were verified by Materials Studio7.0 (MS). The results indicated that we had prepared the W/O petroleum ether microemulsion successfully. When n-octyl alcohol was co-surfactant, pseudo-ternary phase diagrams showed that the area of microemulsion region was the largest, the value of ΔGθo→i was lowest and it was -4.7298kJ•mol-1, average particle size was 68.06nm. Surface tension reached 24.618mN/m when the mass concentration of microemulsion was 0.5%. Molecular dynamics indicated that the χ and Emix CTAB/n-octyl alcohol mixing system were 10.4832 and 6.2080kJ•mol-1 and TX-10/n-octyl alcohol mixing system were 11.5286 and 6.8271kJ•mol-1, respectively. So the compatibility of surfactant / n-octyl alcohol mixing system was the best and interaction was strongest. Compared with others, n-octyl alcohol was the most suitable co-surfactant for this system.
