A New solubility model for competing effects of three solvents: Water, ethanol, and supercritical carbon dioxide

Extraction of iron and calcium from low rank coal by supercritical carbon dioxide with entrainers

Solvent effect on the distribution equilibrium of 8-quinolinol derivatives between supercritical carbon dioxide and water

A measuring method for the distribution behavior between supercritical carbon dioxide and water by a microchip was developed. A surface modification of the microchannel by dichlorodimethylsilane induced a spontaneous phase separation of the supercritical carbon dioxide and aqueous phases in the microchip. The maximum contact time of the aqueous phase to the supercritical carbon dioxide phase was obtained as 0.58 s. This device withstood pressure up to 12.8 MPa. The distribution of tris(acetylacetonato)cobalt(III) (Co(acac)(3)) from the supercritical carbon dioxide phase to the aqueous phase in a microchannel could be measured. The concentration of Co(acac)(3) distributed into the aqueous phase was increased by lengthening the contact time of both phases. These demonstrations showed that the method developed in this study could be used to measure the distribution behavior between supercritical carbon dioxide and water.

Preliminary Evaluation of Polymer-Based Drug Composite Microparticle Production by Coacervate Desolvation with Supercritical Carbon Dioxide

Measurement and correlation of the solubility of two steroid drugs in supercritical carbon dioxide using semi empirical models

Corrosion behavior of ferritic and ferritic-martensitic steels in supercritical carbon dioxide

'This report summarizes the results of work done during the first 1.3 years of a three year project. During the first nine months effort focussed on the design, construction and testing of a closed recirculating system that can be used to study photochemistry in supercritical carbon dioxide at pressures up to 5,000 psi and temperatures up to about 50 C. This was followed by a period of work in which the photocatalytic oxidation of benzene and acetone in supercritical, liquid, and gaseous carbon dioxide containing dissolved oxygen was demonstrated. The photocatalyst was titanium dioxide supported on glass spheres. This was the first time it was possible to observe photocatalytic oxidation in a supercritical fluid and to compare reaction in the three fluid phases of a solvent. This also demonstrated that it is possible to purify supercritical and liquid carbon dioxide using photochemical oxidation with no chemical additions other than oxygen. The oxidation of benzene produced no intermediates detectable using on line spectroscopic analysis or by gas chromatographic analysis of samples taken from the flow system. The catalyst surface did darken as the reaction proceeded indicating that oxidation products were accumulating on the surface. This is analogous to the behavior of aromatic compounds in air phase photocatalytic oxidation. The reaction of acetone under similar conditions resulted in the formation of low levels of by-products. Two were identified as products of the reaction of acetone with itself (4-methyl-3-penten-2-one and 4-hydroxy-4-methyl-2-pentanone) using gas chromatography with a mass spectrometer detector. Two other by-products also appear to be from the self-reaction of acetone. By-products of this type had not been observed in prior studies of the gas-phase photocatalytic oxidation of acetone. The by-products that have been observed can also be oxidized under the treatment conditions. The above results establish that photocatalytic oxidation of organic compounds in supercritical carbon dioxide can be achieved. Until recently it was not possible for us to obtain high quality, quantitative kinetic data. The original flow cell used to obtain UV-Visible spectra on the recirculating fluid did not provide quantitative concentration data because the sapphire windows did not have adequate transmission characteristics below about 240 nm. A pair of windows with better transmission properties arrived as this report was being prepared. While waiting for the replacement windows for the flow cell, the concentration of reactants was monitored by withdrawing samples of the fluid stream for gas chromatographic analysis. This allowed progress to be made in determining some of the factors that affected the rates of reaction in a qualitative sense but the results had large error bars due to the difficulty in obtaining reproducible samples from the pressurized system using gas tight syringes. This problem was recently solved by incorporating a gas chromatograph with automatic sampling valves into the flow system. The two on line analytical methods will now result in reliable analytical data that can be used to follow the reaction kinetics and detect and identify reaction intermediates and by-products, if any are formed.'

Effect of organic solvents on membrane formation by phase separation with supercritical CO 2

Influence of supercritical CO2 on bentonite properties

Transport properties of mixtures composed of acetone, water, and supercritical carbon dioxide by molecular dynamics simulation

We report the study of supercritical flow of carbon dioxide in a vertical tube under non-uniform heat flux. The investigation of supercritical fluid is crucial for advanced generation IV (GIF) nuclear reactors since both supercritical carbon dioxide and supercritical water are planned to be used in those designs. The supercritical carbon dioxide is going to be used in secondary loop of liquid metal fast reactors, the supercritical water will be used as a coolant itself. Thanks to scaling parameters for fluid-to-fluid modelling at supercritical conditions based on inlet conditions approach it is possible to predict response for different supercritical fluids at different scaled conditions. Hence, the results can be used for investigation of other supercritical fluids if it is needed. Since, the heat flux in particular fuel element varies axially it is imperative to investigate the influence of non-uniform flux in this direction. Current literature provides experimental results only when uniform heat flux is applied, whereas non-uniform heat flux can show the thermal response at different stage of fuel cycle. Hence, it is possible to simulate how the flow behaves from the beginning of cycle (BOC) when the shape of the curve is a cosine distributed to the end of cycle (EOC) moment when the peaking factor is skewed to the bottom of the fuel element. The numerical investigation is performed for a 2-D axisymmetric model of a tube with use of CFD code. First, the model is validated for a case with uniform heat flux against results found in the literature. Then, non-uniform heat flux is represented with two parameter equation to describe the variation along axial direction. Sensitivity study related to influence of pressure, temperature and average heat flux in order to better understand the phenomena are conducted. Obtained results provide information about heat transfer coefficient (HTC), heat transfer deterioration (HTD) in supercritical conditions and which parameters can influence it. With better understanding of this phenomena it is possible to prevent or to avoid it, since HTD may cause overheating of the fuel elements inside reactor core and lead to an accident.

Solubilities of four macrolide antibiotics in supercritical carbon dioxide and their correlations using semi-empirical models

Determination of the solubility of rivaroxaban (anticoagulant drug, for the treatment and prevention of blood clotting) in supercritical carbon dioxide: Experimental data and correlations

Extraction of phenolic compounds from pepper-rosmarin (Lippia sidoides Cham.) leaves by sequential extraction in fixed bed extractor using supercritical CO2, ethanol and water as solvents

Extracts from the leaves of Baccharis dracunculifolia obtained by a combination of extraction processes with supercritical CO2, ethanol and water