1. Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606-7905, Micell Technologies, 7516 Precision Drive, Raleigh, North Carolina 27617, Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, and Supercritical Fluid Research Laboratory, Energy and Environment Research Division, Korea Institute of Science and Technology (KIST), 39-1 Hawolgok-dong, Seongbuk-gu, Seoul, 136-791, Korea