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Yoo, Ki Pung,Shin, Hun Yong,Noh, Min Jeong,You, Seong Sik 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.5
To design a supercritical fluid extraction process for the separation of bioactive substances from natural products, a quantitative knowledge of phase equilibria between target biosolutes and solvent is necessary. However, mostly no such information is available in literature to date. Thus in the present study, illustratively the solubility of bioactive coumarin and its various derivatives (i.e., hydroxy-, methyl-, and methoxy-derivatives) in supercritical CO₂ were measured at 308.15-328.15 K and 10-30 MPa. Also, the pure physical properties such as normal boiling point, critical constants, acentric factor, molar volume and standard vapor pressure for coumarin and its derivatives were estimated. By these estimated information, the measured solubilities were quantitatively correlated by an approximate lattice equation of state proposed recently by the present authors.
Rediscovering the Lattice - Fluid Thoery for Phase Equilibria of Complex Mixtures
Yoo,Ki Pung,Lee,Chul Soo 한국화학공학회 2000 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.38 No.3
Various lattice statistical-thermodynamic theories after E. A. Guggenheim [Guggenheim, 1952] have been proposed with different assumptions on nonrandomness, the explicitness of the solution, and the model parameters. During the last decade, the present authors proposed a general approximation tool to the quasichemical solution of the nonrandom lattice-fluid combinatory and formulated a new rigorous EOS and the improved versions including the unified group contribution extensions and systems with strong association. In this study, developments of those EOSs are discussed with emphasis on the practical utility of each model.
Effects of Basic Modifiers on SFE Efficiencies of Ephedrine Derivatives from Plant Matrix
Yoo, Ki Pung,Kim, Jin Yeol 한국화학공학회 2000 Korean Journal of Chemical Engineering Vol.17 No.6
The effect of basified modifiers in supercritical CO₂( SCF-CO₂) such as diethylamine has been investigated on the SFE efficiencies of ephedrine derivatives (e.g. methylephedrine, norephedrine, ephedrine, and pseudoephedrine) from aerial parts of Ephedra sinica. The addition of basified modifiers in SCF-CO₂showed a greater enhancement of SFE efficiency of ephedrine derivatives than pure modifiers. These results might be due to the fact that the salts of Ephedra alkaloids (insoluble in CO₂) in plant tissues would be changed to their free bases (freely soluble in CO₂) by basified modifiers such as diethylamine in methanol. In addition to enhancing the solubilities, it could increase the degree of desorption of the compounds from plant matrix. Also, the SCF-CO₂modified with methanol basified with diethylamine showed a difference of extractability of ephedrine and its diastereomer, pseudoephedrine.
( Ki Pung Yoo ),( Hun Yong Shin ),( Min Jeong Noh ),( Seong Sik You ) 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.5
To design a supercritical fluid extraction process for the separation of bioactive substances from natural products, a quantitative knowledge of phase equilibria between target biosolutes and solvent is necessary. However, mostly no such information is available in literature to date. Thus in the present study, illustratively the solubility of bioactive coumarin and its various derivatives (i.e., hydroxy-, methyl-, and methoxy-derivatives) in supercritical CO₂ were measured at 308.15-328.15 K and 10-30 MPa. Also, the pure physical properties such as normal boiling point, critical constants, acentric factor, molar volume and standard vapor pressure for coumarin and its derivatives were estimated. By these estimated information, the measured solubilities were quantitatively correlated by an approximate lattice equation of state proposed recently by the present authors.
Yoo, Ki Pung,Shin, Hun Yong,You, Seong Sik,Choi, Eun Sun 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.4
The solubility of isomeric o-, m- and p-coumaric acids in supercritical carbon dioxide were measured by a flow-type experimental apparatus at 308.15-323.15 K and 8.5-25 MPa. The data were modeled by an empirical density-based correlation and a recent EOS formulated by the authors based on approximated lattice-hole theory. We found that m-coumaric acid showed the highest solubility and o-coumaric acid showed the lowest solubility at the experimental pressures and temperatures.