نتایج جستجو برای: supercritical carbon dixide
تعداد نتایج: 289203 فیلتر نتایج به سال:
supercritical carbon dioxide (sc-co2) was used as solvent to synthesize oleyl oleate as an analog of jojoba oil from oleic acid and oleyl alcohol with high conversion (100%) of the acid into ester in a short time of 100 min. utilizing a low cost solid catalyst, p-toluenesulfonic acid monohydrate (ptsa), the esterification reaction was performed, without any prior preparation step, in a flow mod...
in the paper we developed a new method to determine the absolute amount of adsorption. this method relies on the excess adsorption isotherm and the density profile in the pore of one material. to compute the density profile and decrease complex calculation of obtaining the absolute amount of adsorption we introduced simplified local-density (sld) model. a few of appropriate parameters were acqu...
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 wa...
solubility of high molecular weight n-paraffins in supercritical carbon dioxide has been a matter of interest to many researchers. however, not sufficient solubility experimental data are available although the methods by which the experimental data are obtained have many varieties. utilizing cubic equations of state is an effective method for solubility prediction of n-paraffins in supercritic...
In recent years, the use of supercritical fluids (SCFs) for the synthesis and processing of nanomaterials has proven to be a rapid, direct, and clean approach to develop nanomaterials and nanocomposites. The application of supercritical fluid technology can result in products (and processes) that are cleaner, less expensive, and of higher quality than those that are produced using conventional ...
We compute the thermal conductivity and diffusion coefficient of supercritical carbon dioxide along the 313 K isotherm using non-equilibrium molecular dynamics. Comparisons are made with experiment at four densities corresponding to pressures of 30, 70, 200 and 500 bar. Two intermolecular potential models for carbon dioxide are compared. INTRODUCTION In a previous paper (Wang and Cummings, 1988...
The demand for a new solvent to treat oilsands was behind the purpose of this project; molecular dynamics simulation was used in this study. Supercritical water, supercritical carbon dioxide and other selected organic solvents in their supercritical state were studied. Meso-tetraphenyl porphyrin (H2TPP) and Octaethyl porphyrin (H2OEP) are the porphyrin model compounds and, 4’-Bis-(2-pyren-1-yl-...
The axial dispersion coefficient of hexachlorobenzene in supercritical carbon dioxide is investigated in a fixed-bed packed with glass beads. The on-line chromatographic pulse-response experiment is used in order to study the dynamics of a packed column under supercritical conditions. The radial dispersion is assumed negligible because of the packed column geometry. To estimate the axial disper...
Deoxypodophyllotoxin is present in the roots of Anthriscus sylvestris. This compound is cytotoxic on its own, but it can also be converted into podophyllotoxin, which is in high demand as a precursor for the important anticancer drugs etoposide and teniposide. In this study, deoxypodophyllotoxin is extracted from A. sylvestris roots by supercritical carbon dioxide extraction. The process is sim...
Supercritical fluids have received much attention for analytical and processing applications. In particular, supercritical carbon dioxide has been used to extract relatively non-polar organics from a variety of environmental matrices, and has also been used for chemical processing. While supercritical carbon dioxide is relatively unreactive and is not an efficient solvent for polar organics, su...
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