화학공학소재연구정보센터
Korean Chemical Engineering Research, Vol.42, No.2, 175-180, April, 2004
Sodium Salt of Bis (2,2,3,3,4,4,5,5-octafluoro-1-pentanol) Sulfosuccinate를 이용한 초임계 CO2+ 물 계의 마이크로에멀젼
Water-in-Supercritical CO2 Microemulsion with Sodium Salt of Bis(2,2,3,3,4,4,5,5-octafluoro-1-pentanol) Sulfosuccinate
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초록
대부분의 촉매, 이온, 단백질같이 비휘발성이고 친수성인 물질들은 초임계 이산화탄소에서는 잘 용해되지 않는 단점을 가지고 있다. 이는 이산화탄소가 무극성이며, 극성인 물에 대해 용해력이 매우 낮기 때문이다. 본 연구에서는 이러한 한계를 극복하기 위한 방법으로, 물과 이산화탄소의 마이크로에멀젼 형성에 관한 연구를 실시하였다. 물과 이산화탄소의 에멀젼을 형성시키기 위하여 친수기와 친이산화탄소기를 동시에 지닌 hydrocarbon-fluorocarbon hybrid 계면활성제인 sodium salt of bis(2,2,3,3,4,4,5,5-octafluo-ro-1-pentanol) sulfosuccinate(F-AOT)를 합성하였다. 기초 데이터로 초임계 이산화탄소내에서 계면활성제의 용해도를 알아보기 위해 variable volume cell을 이용하여 계면활성제의 농도에 따른 cloud point를 측정하였고, 또한, 물+계면활성제+이산화탄소계의 cloud point측정을 통하여 마이크로에멀젼이 안정적으로 형성되는 '마이크로에멀젼 안정 영역'을 구하였다. 초임계 CO2+물 계의 마이크로에멀젼은 온도 308.34에서 368.25 K까지, 압력 14.06에서 63.41 MPa까지의 조건에서 안정적으로 형성되었다.
Non-volatile hydrophilic substances such as ions, proteins, and catalysts have disadvantage that they are insoluble in liquid or supercritical CO2 because of its very low dielectric constant and polarizability per volume. To overcome this disadvantage, we investigated the formation of the water-in-CO2 microemulsion that nano size water droplets were dispersed into CO2. In order to form this microemulsion, the fluorocarbon-hydrocarbon hybrid surfactant, that is, the sodium salt of bis (2,2,3,3,4,4,5,5-octafluoro-1-pentanol) sulfosuccinate (F-AOT) which has CO2 philic chains and hydrophilic head group simultaneously was synthesized. To investigate the solubility of this surfactant in CO2, the cloud point was measured with its various concentrations. And "the stability region of microemulsion" was also obtained by measuring the cloud point of water-in-CO2 microemulsion. It was found that the water-in-CO2 microemulsion was stably formed in the temperature range from 308.34 to 368.25 K, and in the pressure range from 14.06 to 63.41 MPa.
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