نتایج جستجو برای: supercritical co2
تعداد نتایج: 79357 فیلتر نتایج به سال:
Selective aerobic oxidation of benzylic alcohols and of activated aromatic hydrocarbons occurs in supercritical CO2 as reaction medium using H5PV2Mo10O40 as a quasi-heterogeneous catalyst without further additives or co-solvents; efficient recycling is possible and no metal leaching is detectable in the product stream.
Background and Objectives: Supercritical fluid extraction (SFE) technique has been studied for extraction of bioactive compounds from Feijoa sellowiana leaves. Results were compared with those obtained from conventional ethanolic extraction (CE). Materials and Methods: Results: The best supercritical carbon dioxide (SC-CO2) extraction conditions was determined as 250 bar of pressure, 50 °...
Preliminary communication The interest in high pressure technology during last decades increased intensively. Supercritical Fluid Extraction (SFE) is a process that is growing in importance as an alternative to conventional separation processes. SFE uses environmentally friendly CO2 as the extracting agent in the process because of its relatively low critical pressure (7,38 MPa), its low critic...
Feasibility of drilling with supercritical carbon dioxide to serve the needs of deep underbalanced drilling operations has been analyzed. A case study involving underbalanced drilling to access a depleted gas reservoir is used to illustrate the need for such a research. For this well, nitrogen was initially considered as the drilling fluid. Dry nitrogen, due to its low density, was unable to ge...
samples of crushed and cooked canola seeds (okapy double zero) were extracted using supercritical carbon dioxide (scco2) at 34 mpa and 40ºc and a commercial organic solvent (aw406). the oil solubility in scco2 was determined and extracted oils were examined with respect to their chlorophyll contents, nonsaponifiable matters, fatty acid composition and iodine value. the yield of scco2 extraction...
Global warming due to the accumulation of atmospheric CO2 has received widespread attention in recent years. Although various CO2 capture technologies have been proposed, using the captured CO2 from power plants is increasingly popular because of concerns with regard to the safety of underground and ocean CO2 storage. Various techniques related to utilization of CO2 from the exhausted gas of po...
The further development of new processes utilizing liquid or supercritical CO2 as a solvent will benefit from the rational design of new CO2-philes. Understanding solvation structures and mechanisms of these molecules is an important part of this process. In such studies, determining the change in density as a function of the measured thermodynamic conditions (pressure and temperature) provides...
The effects of process parameters on the extraction of Ginkgo biloba L. leaves with supercritical carbon dioxide were investigated. The investigated parameters include particle size (mean particle diameter 0.19, 0.467 and 1.009 mm), solvent flow rate (1.58×10, 3.22×10 and 4.16×10 kg CO2/min) and pressure (100–300 bar), which were obtained by the response surface methodology (RSM) under the foll...
Supercritical carbon dioxide (SC-CO2 ) has been used for the first time as a reaction medium for the dehydration of glycerol to acrolein catalyzed by a solid acid. Unprecedented catalyst stability over 528 hours of time-on-stream was achieved and the rate of coke deposition on the zeolite catalyst was the lowest among extensive previous studies, showing potential for industrial application. Cok...
The state of aggregation of water dissolved in supercritical carbon dioxide has been investigated under isobaric heating (T=40-340°C, P=250 bar) using infrared absorption and Raman scattering spectroscopies. Quantitative analysis of experimental spectra has shown that below 100°C, water exists only in its monomeric form (solitary water surrounded by CO2 molecules) whereas H-bonded species, name...
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