Distribution of Solutes Between Polymer and Supercritical Fluid by Inverse Supercritical Fluid Chromatography

Jae-JinShim 한국화학공학회 2002 Korean Journal of Chemical Engineering Vol.19 No.1

methods of inverse supercritical fluid chromatography (ISFC), frontal analysis supercritical fluid chro-matography (SFC) and elution SFC, have been compared for the determination of distribution coefficients of solutesbetween a polymer and a supercritical CO2. The logarithm of the distribution coefficient showed monotonic decreasewith the density of the supercritical fluid (SF). The abnormal-maximum behavior of solute sorption in the polymerphase was explained by the fluid and solute properties, f2P/P2sat. Interesting open-elliptic shapes of sorption and volume-fraction curves were obtained and explained with the fugacity coeficient. Corection to the capacity factor was em-ployed to eliminate the retention due to the adsorption on the surface of the silica support. A model based on the Floryequation and the Peng-Robinson equation of state (EOS) sucesfully predicted the phase behavior of the ternary solute-supercritical fluid-polymer systems using only interaction parameters obtained from the binary systems. The solutedistribution coefficient at infinite dilution was used to calculate the phase equilibrium at finite concentration using aternary-phase diagram.

초임계유체를 이용한 입자제조

이윤우 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.6

초임계이산화탄소와 초임계수와 같은 초임계유체의 환경친화적 성질은 미세입자를 제조하는 새로운 재료분야의 응용에 많은 관심의 대상이 되고 있다. 최근에는 초임계유체의 저독성과 불연성 그리고 저렴한 가격 때문에 의약품, 화장품, 세라믹, 식품 그리고 폭약 등에서 이를 이용하여 나노 또는 마이크로입자를 제조하는 공정에 많은 이용되고 있다. 본고에서는 초임계유체를 이용하여 미세입자를 제조하는 대표적인 공정인 RESS(rapid expansion of supercritical solution), SAS(supercritical anti solvent) 그리고 PGSS(particles from gas saturated solution) 등에 대하여 중점적으로 소개하고자 한다. The environmentally friendly nature of supercritical fluids such as supercritical carbon dioxide and supercritical water has led to the exploration of their use in a range of materials applications. In the last few years, several supercritical fluids-based techniques have been proposed for the production of micronic and nanometric particles for potential applications in areas such as pharmaceuticals. cosmetics, inorganics, hiomaterials and explosives. Techniques like the rapid expansion of supercritical solutions (RESS), supercritical antisolvent precipitation (SAS), particle generation from gas-saturated solutions (PGSS), and reactive precipitation in supercritical solutions (RPSS) have been critically reviewed.

Distribution of Solutes Between Polymer and Supercritical Fluid by Inverse Supercritical Fluid Chromatography

Shim, Jae-Jin 한국화학공학회 2002 Korean Journal of Chemical Engineering Vol.19 No.1

Two methods of inverse supercritical fluid chromatography (ISFC), frontal analysis supercritical fluid chromatography (SFC) and elution SFC, have been compared for the determination of distribution coefficients of solutes between a polymer and a supercritical CO_2. The logarithm of the distribution coefficient showed monotonic decrease with the density of the supercritical fluid (SF). The abnormal-maximum behavior of solute sorption in the polymer phase was explained by the fluid and solute properties, ø_2P/P_2^sai. Interesting open-elliptic shapes of sorption and volumefraction curves were obtained and explained with the fugacity coefficient. Correction to the capacity factor was employed to eliminate the retention due to the adsorption on the surface of the silica support. A model based on the Flory equation and the Peng-Robinson equation of state (EOS) successfully predicted the phase behavior of the ternary solutesupercritical fluid-polymer systems using only interaction parameters obtained from the binary systems. The solute distribution coefficient at infinite dilution was used to calculate the phase equilibrium at finite concentration using a ternary-phase diagram.

Development of artificial neural network models for supercritical fluid solvency in presence of co-solvents

Eissa Mohamed El-Moghawry Shokir,Emad Souliman Al-Homadhi,Osama Al-Mahdy,Ayman Abdel-Hamid El-Midany 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.8

This paper presents the application of artificial neural networks (ANN) to develop new models of liquidsolvent dissolution of supercritical fluids with solutes in the presence of cosolvents. The neural network model of theliquid solvent dissolution of CO2 was built as a function of pressure, temperature, and concentrations of the solutesand cosolvents. Different experimental measurements of liquid solvent dissolution of supercritical fluids (CO2) withsolutes in the presence of cosolvents were collected. The collected data are divided into two parts. The first part wasused in building the models, and the second part was used to test and validate the developed models against the Peng-Robinson equation of state. The developed ANN models showed high accuracy, within the studied variables range,in predicting the solubility of the 2-naphthol, anthracene, and aspirin in the supercritical fluid in the presence and absenceof co-solvents compared to (EoS). Therefore, the developed ANN models could be considered as a good tool in predictingthe solubility of tested solutes in supercritical fluid.

Manufacturing Polymer/clay Nanocomposites Using a Supercritical Fluid Process

Jung, Hyun-Taek,Yoon, Ho-Gyu,Lim, Soon-Ho Korean Society for Precision Engineering 2008 International Journal of Precision Engineering and Vol.9 No.4

The increased interest in reducing the environmental effects caused by releasing organic compounds and aqueous waste has motivated the development of polymeric materials in supercritical fluids. Recently, supercritical fluids have been used in material synthesis and processing because of their special properties, such as high diffusivity, low viscosity, and low surface tension. Supercritical carbon dioxide is the most attractive because it is non-toxic, non-flammable, and has moderate critical temperature and critical pressure values. Supercritical carbon dioxide can also swell most polymers. In this study, we prepared polymer/clay nanocomposites using supercritical fluids. Cloisites 10A, 15A, 25A, and 30B used in this study are montmorillonites modified with a quaternary ammonium salt. The nanocomposites of polymer/clay were characterized by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry.

상태방정식을 이용한 디클로로메탄/이산화탄소 혼합 용매의 열역학적 거동 연구

권웅,이권윤,정의경,Kwon, Woong,Lee, Kwonyun,Jeong, Euigyung 한국섬유공학회 2022 한국섬유공학회지 Vol.59 No.5

Single- or multi-component supercritical fluids, which exhibit excellent solubility in polymers, are used as solvents in polymer-based industries. Because their properties change easily with volume, temperature, and pressure, the use of single- or multi-component supercritical fluids in industrial applications requires the supercritical fluid apparatus to be designed according to the required volume, temperature, and pressure. Supercritical fluid apparatus design and optimization can benefit greatly from the analysis and understanding of the thermodynamic behavior of single- or multi-component fluids. Therefore, this study investigated the correlation between the composition ratio of a dichloromethane/carbon dioxide mixture and pressure at 200 ℃ using ideal gas, van der Waals, Redlich-Kwong, Soave-Redlich-Kwong, and Peng-Robinson equations of state. The critical temperature according to the compositional change of the dichloromethane/carbon dioxide mixture was predicted by the basic mixing rule. This analysis of the thermodynamic behavior of the dichloromethane/carbon dioxide mixture can be used for optimizing supercritical fluid apparatuses.

Manufacturing Polymer/clay Nanocomposites Using a Supercritical Fluid Process

Hyun-Taek Jung,Ho Gyu Yoon,Soonho Lim 한국정밀공학회 2008 International Journal of Precision Engineering and Vol.9 No.4

The increased interest in reducing the environmental effects caused by releasing organic compounds and aqueous waste has motivated the development of polymeric materials in supercritical fluids. Recently, supercritical fluids have been used in material synthesis and processing because of their special properties, such as high diffusivity, low viscosity, and low surface tension. Supercritical carbon dioxide is the most attractive because it is non-toxic, non-flammable, and has moderate critical temperature and critical pressure values. Supercritical carbon dioxide can also swell most polymers. In this study, we prepared polymer/clay nanocomposites using supercritical fluids. Cloisites 10A, l5A, 25A, and 30B used in this study are montmorillonites modified with a quaternary ammonium salt. The nanocomposites of polymer/clay were characterized by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry.

Preparation of PBT/clay Nanocomposites using Supercritical Process

홍영기,윤호규,임순호 한국정밀공학회 2009 International Journal of Precision Engineering and Vol. No.

Butylene terephthalate cyclic (BTC) oligomers have been successfully polymerized to a poly(buthylene terephthalate) (PBT) employing the advantages of the low viscosity of cyclic oligomers and high solubility, high transport property of supercritical fluids. The ring-opening polymerization of BTC oligomers initiated by various mol concentration of catalyst (cyclic stannoxane 1) is carried out in supercritical chlorodifluoromethane (HCFC- 22) at temperature ranging from 160 to 220 ℃, at pressure ranging from 150 to 410 bar and at time ranging from 2 to 10 hrs. The highest molecular weight was obtained at 190 ℃, 410 bar and 4 mol% mol concentration of catalyst. The results of XRD and TEM show that some of clays are intercalated or disordered, consisting of about 2-10 parallel silicate layers to form morphology like thin thread and some of clays are collapsed. The modulus and tensile strength of the nanocomposites prepared by supercritical process were higher than those of nanocomposites prepared by melt process.

Supercritical fluid-mediated liposomes containing cyclosporin A for the treatment of dry eye syndrome in a rabbit model: comparative study with the conventional cyclosporin A emulsion

Karn, Pankaj Ranjan,Kim, Hyun Do,Kang, Han,Sun, Bo Kyung,Jin, Su-Eon,Hwang, Sung-Joo Dove Medical Press 2014 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.9 No.-

<P><B>Background</B></P><P>The objective of this study was to compare the efficacy of cyclosporin (CsA)-encapsulated liposomes with the commercially available CsA emulsion (Restasis<SUP>®</SUP>) for the treatment of dry eye syndrome in rabbits.</P><P><B>Methods</B></P><P>Liposomes containing CsA were prepared by the supercritical fluid (SCF) method consisted of phosphatidylcholine from soybean (SCF-S100) and egg lecithins (SCF-EPCS). An in vitro permeation study was carried out using artificial cellulose membrane in Franz diffusion cells. Dry eye syndrome was induced in male albino rabbits and further subdivided into untreated, Restasis<SUP>®</SUP>-treated, EPCS, and S100-treated groups. Tear formation in the dry-eye-induced rabbits was evaluated using the Schirmer tear test. All formulations were also evaluated by ocular irritation tests using the Draize eye and winking methods with the determination of CsA concentration in rabbit tears.</P><P><B>Results</B></P><P>After the treatment, the Schirmer tear test value significantly improved in EPCS-treated (<I>P</I>=0.005) and S100-treated (<I>P</I>=0.018) groups compared to the Restasis<SUP>®</SUP>-treated group. The AUC<SUB>0–24 h</SUB> for rabbit’s tear film after the administration of SCF-S100 was 32.75±9.21 μg·h/mg which was significantly higher than that of 24.59±8.69 μg·h/mg reported with Restasis<SUP>®</SUP>. Liposomal CsA formulations used in this study showed lower irritation in rabbit eyes compared with Restasis<SUP>®</SUP>.</P><P><B>Conclusion</B></P><P>These results demonstrate that the novel SCF-mediated liposomal CsA promises a significant improvement in overcoming the challenges associated with the treatment of dry eyes.</P>

초임계 유체를 이용한 광촉매용 나노크기의 결정질 $TiO_2$ 분말 제조

임대영,김종옥,김택남,이채현,박원규,Lim, Dae-Young,Kim, Jong-Ock,Kim, Taik-Nam,Lee, Chae-Hyun,Park, Won-Kyu 배재대학교 공학연구소 1998 공학논문집 Vol.3 No.1

습식화학법의 단점을 극복하는 이상적인 분말을 제조하기 위해서는 용질분자가 용액내에서 활발하게 움직여서 분자단위의 혼합이 가능하고 용매는 낮은 점도를 가져 용질분자의 움직임에 도움을 주어야 하며, 얻어진 분말도 결정질이어야 한다. 본 논문에서는 이러한 조건을 동시에 만족시키는 분말제조방법으로 물질의 임계온도, 임계압력을 넘어 응축된 가스상태로 존재하는 초임계 유체를 이용하여 분말을 제조하였다. 용매인 에탄올이 초임계 유체상태에서 분해될 때 생성된 물로 titanium(IV) ethoxide를 가수분해시켜 이용도가 높은 광촉매용 $TiO_2$ 분말을 제조하였다. In order to fabricate ideal powders, new processing is necessary in which the solute atoms in solution rapidly move to mix each other to the degree of molecular level, the viscosity of solution should be low not to effect the moving of solute atoms, and the powders could be directly obtained as crystalline. Supercritical fluid is defined as condensed gas state up to its critical pressure and temperature. In this paper, supercritical fluid methods were studied as a new ceramic processing of powder preparation. The crystalline anatase powders of $TiO_2$ which are useful for photocatalyst materials were fabricated by hydrolysis of titanium(IV) ethoxide using water which was ethanol as a supercritical fluid.