Search results for " carbon dioxide"
showing 10 items of 200 documents
Epoxidation of Olefins with a Silica-Supported Peracid in Supercritical Carbon Dioxide under Flow Conditions
2012
Anhydrous 2-percarboxyethyl-functionalized silica (2b), a recyclable supported peracid, is a suitable reagent to perform the epoxidation of alkenes 1 in supercritical carbon dioxide at 250 bar and 40 °C under flow conditions. This procedure simplifies the isolation of the reaction products and uses only carbon dioxide as a solvent under mild conditions. The solid reagent 2b can be easily recycled by a reaction with 30% hydrogen peroxide in an acid medium.
CCDC 1891591: Experimental Crystal Structure Determination
2019
Related Article: Marta Mon, Rosaria Bruno, Estefanía Tiburcio, Aida Grau-Atienza, Antonio Sepúlveda-Escribano, Enrique V. Ramos-Fernandez, Alessio Fuoco, Elisa Esposito, Marcello Monteleone, Johannes C. Jansen, Joan Cano, Jesús Ferrando-Soria, Donatella Armentano, Emilio Pardo|2019|Chem.Mater.|31|5856|doi:10.1021/acs.chemmater.9b01995
CCDC 1473649: Experimental Crystal Structure Determination
2017
Related Article: Mónica Giménez-Marqués, Néstor Calvo Galve, Miguel Palomino, Susana Valencia, Fernando Rey, Germán Sastre, Iñigo J. Vitórica-Yrezábal, Mónica Jiménez-Ruiz, J. Alberto Rodríguez-Velamazán, Miguel A. González, José L. Jordá, Eugenio Coronado, Guillermo Mínguez Espallargas|2017|Chemical Science|8|3109|doi:10.1039/C6SC05122G
Effects of ocean acidification on embryonic respiration and development of a temperate wrasse living along a natural CO2 gradient
2016
Volcanic CO2 seeps provide opportunities to investigate the effects of ocean acidification on organisms in the wild. To understand the influence of increasing CO2 concentrations on the metabolic rate (oxygen consumption) and the development of ocellated wrasse early life stages, we ran two field experiments, collecting embryos from nesting sites with different partial pressures of CO2 [pCO2; ambient (400 µatm) and high (800-1000 µatm)] and reciprocally transplanting embryos from ambient- to high-CO2 sites for 30 h. Ocellated wrasse offspring brooded in different CO2 conditions had similar responses, but after transplanting portions of nests to the high-CO2 site, embryos from parents that sp…
Free radical copolymerization of vinylidene fluoride and acrylic acid in supercritical carbon dioxide
2010
Preparation of drug-polymer composites by polymerization in supercritical carbon dioxide: a new method to increase the dissolution rate of bioactive …
2008
Structure and pair correlations of a simple coarse grained model for supercritical carbon dioxide
2009
A recently introduced coarse-grained pair potential for carbon dioxide molecules is used to compute structural properties in the supercritical region near the critical point, applying Monte Carlo simulations. In this model, molecules are described as point particles, interacting with Lennard-Jones (LJ) forces and a (isotropically averaged) quadrupole–quadrupole potential, the LJ parameters being chosen such that gratifying agreement with the experimental phase diagram near the critical point is obtained. It is shown that the model gives also a reasonable account of the pair correlation function, although in the nearest neighbour shell some systematic discrepancies between the model predicti…
Extraction of wheat germ oil by supercritical CO2 : Oil and defatted cake characterization
2003
In this paper the working conditions for the extraction of wheat germ oil in a supercritical CO2 pilot plant of 1-L extraction capacity were studied. The best conditions were: pressure, 38 MPa; temperature, 55degreesC; wheat germ particle size, about 0.35 mm; CO2 flow rate, 1.5 L min(-1). These conditions gave yields of about 92% of total oil after 3 h of processing. The obtained oils and the partially defatted cake were investigated with regard to their FA, tocol (tocopherol and tocotrienol), carotenoid, and sterol compositions and to their quality characteristics (FFA, PV, para-anisidine value, and color of the by-product). Moreover, the oil quality was evaluated in relation to the progre…
Supercritical CO2 extraction of essential oil from orange peel; effect of the height of the bed
2000
Abstract The influence of the height of the particle bed on the kinetics of supercritical fluid extraction (SFE) of essential oil from orange peel is analyzed in this article. Peel of dehydrated oranges of the satsuma and naveline cultivars was used. A series of experiments were designed wherein, for the same conditions, particle height varied widely. These experiments were also carried out on different scales with extraction volumes of 0.5 and 5 l. The results of the experiments were interpreted using Sovova's extended flow model as has been done in previous studies. The bibliography indicates that a number of phenomena may distort the process. One of these phenomena is the formation of ma…
Effective recovery of perfluoropolyether surfactants from PVDF and PTFE by supercritical carbon dioxide extraction
2007
Abstract The extraction of ammonium carboxylate perfluoropolyether surfactants from poly(vinylidenefluoride) (PVDF) and poly(tetrafluoroethylene) (PTFE) was performed with supercritical carbon dioxide. When proper conditions in terms of temperature, pressure and flow rate were used, extraction recoveries higher than 90% were obtained. For PVDF (with a concentration of surfactant of 5% w/w), at low pressure (12 MPa) and 40 °C, more than 100 min are necessary to have a quantitative extraction. On the other hand, at higher pressure (20 MPa) a quantitative recovery was obtained after few minutes. A strong influence of the temperature on the extraction recovery was also found. In the case of PTF…