화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
Clean Technology, Vol.12, No.3, 128-137, September, 2006
Export Citation
이온성액체/유기화합물/초임계이산화탄소계의 상평형
Phase Equilibria of Ionic Liquid/Organic Compound/Supercritical CO2 Systems
임방현, 김종원, 백상민, 손보국, 이용록, 이철수1, 이흔2, 나춘섭3, 심재진†
  • 영남대학교 공과대학 디스플레이화학공학부, 712-749 경북 경산시 대동 214-1
  • 1고려대학교 화공생명공학과, 136-701 서울시 성북구 안암동 5가 1번지
  • 2한국과학기술원 생명화학공학과, 305-701 대전시 유성구 구성동 373-1
  • 3영남대학교 이과대학 화학과, 712-749 경북 경산시 대동 214-1
Bang-Hyun Lim, Jong-Won Kim, Sang-Min Paek, Bo-Kook Son, Lok-Yong Lee, Chul Soo Lee1, Huen Lee2, Chun-Sup Ra3, and Jae-Jin Shim†
  • School of Display and Chemical Engineering, Yeungnam University, 214-1 Dae-dong, Gyeongsan, Gyeongbuk 712-749, Korea
  • 1Department of Chemical and Biological Engineering, Korea University, 1 Anam-5-dong, Seongbuk-gu, Seoul 136-701, Korea
  • 2Department of Chemical and Biomolecular Engineering, KAIST, 373-1 Guseong-dong, Yusong-gu, Daejon 305-701, Korea
  • 3Department of Chemistry, Yeungnam University, 214-1 Dae-dong, Gyeongsan, Gyeongbuk 712-749, Korea
E-mail:
초록
초임계이산화탄소 내에서 이온성액체의 부피 변화와 상온 이온성액체와 유기화합물의 혼합물이 두 상으로 분리되는 현상을 고압 view cell을 이용하여 측정하였다. 이온성액체(ionic liquid, IL)로는 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6])와 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4])를 사용하였으며, 유기화합물로는 methanol과 dimethyl carbonate를 사용하였다. 일정한 양의 ([bmim][PF6])에 대하여 유기화합물의 양을 증가시킴에 따라 상이 나누어지는 지점인 lower critical end point (LCEP) 압력이 감소하였다. 이온성액체의 수분함량이 증가함에 따라 LCEP가 높게 나타났으며, 일정량 이상의 수분이 함유되어 있으면 LCEP가 나타나지 않았다. LCEP는 같은 부피의 ([bmim][PF6])에서보다 ([bmim][BF4])에서 약 1.0 MPa 정도 높게 나타났으며, K-point는 이온성액체의 종류와 유기화합물의 양에 따라 거의 변화하지 않았다. 초기시료 중 이온성액체 ([bmim][PF6])의 농도 (IL/(IL+MeOH))가 7.23 mol% 보다 크면 혼합물의 LECP에서 L1의 부피가 L2의 부피보다 크게 나타났으며, 반대로 작으면 작게 나타났다. 이산화탄소의 존재 하에서 이온성액체의 부피변화는 온도가 증가함에 따라 감소하였으며, 313.15 와 343.15K 사이 에서는 압력이 증가함에 따라 증가하여 300 bar에서는 원래 부피의 123~126%가 되었다.
The volume change of an ionic liquid and the phase separation behavior of room temperature ionic liquid(RTIL)/organic compound mixture in supercritical carbon dioxide were measured in a high pressure view cell. 1-Butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) was used as ionic liquid(IL). and methanol and dimethyl carbonate were used as organic compound. For a fixed amount of ([bmim][PF6]) the lower critical endpoint (LCEP) pressue, where the liquid phase is split, decreased as increasing the amount of organic compound. The LCEP pressure became higher as the water content of ionic liquid was higher. However, for water contents above a certain value, no LCEP was formed. LCEP appeared 1.0 MPa higher for a mixture with ([bmim][BF4]) than with ([bmim][PF6]). There was almost no difference in the K-point pressures for different types of ionic liquid and for different amounts of organic liquid. When the concentration of ionic liquid([bmim][PF6]) (IL/(IL+MeOH)) in the initial liquid mixture was larger than 5.9 mol% at the LCEP of the mixture, the volume of L1 because larger than the volume of L2. When it was smaller, however, the volume became smaller, too. The volume change of ionic liquid in the presence of carbon dioxide decreased as increasing the temperature, while it increased as increasing the pressure. For temperatures between 313.15 to 343.15K at 300 bar, it was about 123~125% of the original volume.
Keywords:이온성액체;유기화합물;초임계이산화탄소;상평형;아래 임계 끝점(LCEP)
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