Abstract: The scCO₂ microemulsion was formed by supercritical CO₂, water, surfactant AOT and cosurfactant C₂H₅OH under certain pressure and temperature. The minimum miscible pressure of scCO₂ microemulsion and alkanes was determined by a variable volume visible cell. The influences of temperature, water content, carbon number of alkanes and the concentration of AOT on MMP of scCO₂microemulsion and alkanes were also studied. The results show that the MMP of scCO₂microemulsion and alkanes is obviously lower than that of scCO₂and alkanes and the range of decrease of MMP is enlarged with the carbon number of alkanes increasing. With the increasing of AOT concentration, the change of the MMP of scCO₂ microemulsion and dodecane is little. When the water content is low, the MMP of scCO₂ microemulsion and dodecane is lower than that of scCO₂ and dodecane under different temperature. The MMP of scCO₂ microemulsion and dodecane increased as temperature being increased.

Key words: Supercritical CO₂,    ,  Microemulsion,    ,  Minimum miscible pressure(MMP),    ,  Alkanes

摘要： 超临界CO₂微乳液是由超临界CO₂、H₂O、表面活性剂AOT（二（2乙基己基）磺基琥珀酸钠）和助表面活性剂C₂H₅OH在一定温度和压力下形成的。采用体积可变的高压可视装置研究了超临界CO₂微乳液与烷烃的最小混相压力（MMP），考察了烷烃碳数、温度、水和表面活性剂摩尔分数对超临界CO₂微乳液与烷烃的MMP影响。结果表明，超临界CO₂微乳液能明显降低烷烃与CO₂间的最小混相压力，且随烷烃分子结构中碳数增加，最小混相压力降低幅度也越大。随AOT含量增加，超临界CO₂微乳液与十二烷间的最小混相压力变化不大。低水含量时，超临界CO₂微乳液体系与十二烷最小混相压力在各温度下均低于十二烷/CO₂的最小混相压力。超临界CO₂微乳液与十二烷的最小混相压力随温度的升高而增加。

关键词: 超临界二氧化碳, 微乳液 , 最小混相压力 , 烷烃