Hun Yong Shin

Measurement and correlation of solubility of disperse anthraquinone and azo dyes in supercritical carbon dioxide

The solubility of three disperse anthraquinone dyes and two azo dyes in supercritical CO2 was measured. The tested dyes are Celliton fast blue B, l-amino-2-methylanthraquinone, 1-methylaminoanthraquinone, disperse Red 1 and 4-[4-(phynylazo)phenylazo]-o-cresol. Solubility measurements were made at 313.15-393.15 K and 10-25 MPa in a high-temperature autoclave phase equilibrium apparatus. Pure physical properties of the dyes such as critical constants, molar volumes and vapor pressures were estimated based on semi-empirical methods. Also, the data were quantitatively modeled by both an empirical density correlation and a quantitative equation of state recently proposed by the present authors based on nonrandom lattice theory. We found that anthraquinone disperse dyes in general show higher solubility than azo disperse dyes in supercritical CO2 within the experimental ranges.

Measurements and Correlation of Hydrogen-Bonding Vapor Sorption Equilibrium Data of Binary Polymer Solutions

Vapor sorption equilibrium data of ten binary polymer/solvent systems were measured using sorption equilibrium cell equipped with a vacuum electromicrobalance. Tested solvents were water, methanol, ethanol and npropanol and polymer solutes were poly(ethylene glycol), poly(propylene glycol), poly(tetramethylene glycol) and poly(ethylene oxide). The measured sorption obtained in the present work, were compared with existing literature data and the degree of reliability of the measured data was discussed. Vapor sorption equilibrium data obtained in the present study were correlated by UNIQUAC model and the multi-fluid non-random lattice fluid hydrogen bonding equation of state (MF-NLF-HB EOS) recently proposed by the present authors.

Measurement and modeling solubility of bioactive coumarin and its derivatives in supercritical carbon dioxide

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. How-ever, 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.

Rigorous and simplified lattice-hole equations of state for calculating specific volumes of common pure polymers

Specific volumes of common pure polymers such as low- and high-density poly(ethylene), poly(n-butyl methacrylate), poly(styrene), and poly(o-methylstyrene) were calculated by the NLF and the MF-NLF equations of state, which were developed from nonrandom lattice-hole theory. Both models contain only two molecular parameters for a pure r-mer. The NLF model is based on the rigorous approximation of lattice-hole theory and thus it is somewhat complicated in practice. The MF-NLF model is based on the two-fluid approximation of the same lattice-hole theory and thus is relatively more semi-empirical than the NLF, while preserving comparable accuracy. In this work the models were comparatively applied to the calculation of the specific volumes of pure polymers, and the results obtainedto date were presented with emphasis on the practical utility of the models.

A simple two-liquid approximation of lattice theory for modeling thermodynamic properties of complex fluids

Abstract A simple equation of state (EOS) applicable to complex fluids was formulated based on the nonrandom two-liquid approximation of lattice-hole theory. The EOS requires two molecular parameters representing molecular size and interaction energy for a pure fluid, and one additional interaction parameter for a binary mixture. The model quantitatively describes configurational properties of pure fluids and phase equilibria behaviors of mixtures. It gives a good phase equilibria description even for liquid–liquid equilibria of systems containing simple, complex or macromolecular species. To our knowledge, no other approximate molecular theory originating from the classical lattice theories has been presented which describes the entire range of configurational properties of fluids from a practical point of view, although the formulation of the EOS was based on a phenomenological argument in a sense.

Calculation of complex phase equilibria in the critical region of fluid mixture based on multi-fluid lattice equation of state

Quantitative correlation of critical loci and multiphase behaviors has received considerable attention because the increased industrial importance of processes operating within the high-pressure region such as supercritical fluid extraction. However, in the critical region, classical thermodynamic models such as equations of state (EOS) frequently fail to correlate phase equilibrium properties. Recently, the present authors proposed a new lattice-hole EOS based on the multi-fluid approximation of the nonrandom lattice theory. The model requires only two molecular parameters reflecting size and interaction energy for a pure fluid and one additional interaction parameters for a binary mixture. In this work, the reliable applicability of the EOS was demonstrated to various phase equilibria of complex mixtures in the critical region. Demonstration of the EOS was made to calculate multiphase behaviors such as solid-liquidvapor (SLV) equilibria and critical loci of binary complex mixtures at high pressure. For P-T, P-x, and T-ρ phase diagrams tested, the model agrees well with experimental data.

A new two-fluid quasilattice equation of state for calculating physical properties and supercritical phase equilibria

Abstract A new equation of state (EOS) was formulated by the nonrandom two-fluid approximation of the lattice–hole theory. The resulting EOS contains two molecular parameters for a pure fluid and one additional interaction parameter per binary. The model was tested for its applicability over a wide range of density and pressure to pure properties of supercritical fluids and high pressure phase equilibria of mixed systems containing molecules of arbitrary size and shape. Results obtained to date demonstrate that the new EOS correlates quantitatively well the various types of experimental supercritical and multiphase equilibria. To our knowledge, no other molecular theory originated from the classical lattice fluid description has been presented which describes an entire range of densities of pure fluids and mixtures from a unified point of view.

Group contribution multifluid lattice theory for simultaneous predictions of thermodynamic properties of pure fluids and mixtures

Abstract A unified group contribution (GC) lattice equation of state (EOS) was formulated based on the multifluid approximation of the nonrandom lattice fluid theory. The GC-EOS requires segment size and interaction energy parameter from functional group characteristics. The unique feature of the approach is that a single set of group parameters are used for both pure fluids and mixtures. The approach was found to be quantitatively applicable for predicting thermodynamic properties of real pure fluids and mixtures. Its potential utility was demonstrated for vapor pressures, vapor–liquid coexistence densities of pure fluids and phase equilibrium properties of mixtures including polymeric solutions.

Measurement and correlation of solubilities ofo- , m- andp-Coumaric Acid isomers in supercritical Carbon Dioxide

The solubility of isomerico-, 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 thatm-coumaric acid showed the highest solubility and o-coumaric acid showed the lowest solubility at the experimental pressures and temperatures.

Predictive quasilattice equation of state for unified high pressure phase equilibria of pure fluids and mixtures

Publisher Summary Based on a rigorous solution derived from the lattice statistical–mechanical theory, a unified group contribution equation of state (GC-EOS) is formulated. This chapter discusses a unified group contribution equation of state (GC–EOS), which is applicable for the simultaneous prediction of thermodynamic properties of pure fluids and mixtures over a wide range of pressure. The GC–EOS uses a single set of group segment size and interaction energy parameter for both pure fluids and mixtures. Quantitative applicability is demonstrated for the vapor pressures of pure fluids and vapor–liquid equilibrium properties of mixtures with emphasis on the high-pressure region, including the supercritical fluid systems.