Carbon dioxide partition coefficient

In the cases above, a two-parameter model well represents the data. A model with more parameters would be more flexible, but by using a partition constant, K, or a desorption rate constant ka and k, , for the mass-transfer coefficients, the data are well described (see Figs. 3.4-15 and 3.4-13). While K would be a value experimentally determined, kp can be estimated from eqn. (3.4-97) with the external mass-transfer coefficient, km, estimated from the correlation of Stiiber et al. [25] or from that of Tan et al. [27], and the effective diffusivity from the Wakao Smith model [36], Typical values of kp obtained by fitting the data of Tan and Liou are shown in Fig. 3.4-16. As expected, they are below the usual mass-transfer correlations, because internal resistance diminishes the global mass transfer coefficient. These data correspond to the regeneration of spent activated carbon loaded with ethyl acetate, using high-pressure carbon dioxide, published by Tan and Liou [45]. 

Organic solvent(s) Partition coefficients Soluble in carbon dioxide, chloroform ether Insoluble in acetone Soluble in ethanol Soluble in ethanolb Soluble in ethanol, ether... 

Karasek, P, J. Pol, J. Planeta, et al. 2002. Partition coefficients of environmentally important phenols in a supercritical carbon dioxide-water system from concurrent extraction without analysis of the compressible phase. Anal. Chem. 74 4294-4297. 

The overall dispersion coefficient of gas has been observed to increase when a more adsorptive gas is utilized as a tracer for transient response under constant aeration (Stemerding in R4 M33, M42). Figure 62 shows such examples taken for a fluidized cracking catalyst bed (M33), where the partition ratios of adsorptive gas m (equal to Cfe + WsCse) are measured as 0.6, 4.5 and 10 for hydrogen, carbon dioxide, and Freon 12, respectively. Enhancement of gas dispersion by adsorption has also been studied by Yoshida and Kunii (Y15), Yoshida e/ al. (Y17), Yates and Constants (Y9), Zalewski and Hanesian (Z3), and Nguyen and Potter (N2). 

Partition Coefficients of Poly (ethylene glycol) s in Supercritical Carbon Dioxide... 

Flow is an important consideration because of the partitioning coefficient of the analyte between carbon dioxide and the matrix. Higher flows (or long extraction times) may be necessary to sweep all the analyte out of the extraction chamber. Low flows may be necessary if the kinetics of the system are slow. For most SFE separations, extraction takes 20-30 min. 

Here c and are the concentrations of the substance under test in the stationary and mobile phase respectively, F" and F are the volumes of the stationary and mobile phase in the column, and is the retention time of an inert substance. From measurements of and f the capacity ratio k, and from this the partition coefficient K, can be calculated. In Figure 37 experimentally determined log k values are plotted against the density p and the pressure p of supercritical carbon dioxide at 40 C as a mobile phase for SFC experiments with alkanes having between 10 and 30 carbon atoms a chemically bonded stationary phase (Carbowax 400 on Porasil C) was used and further details are given in the caption of Figure 37. > The curves show that with increasing density the retention time f and the capacity ratio k decrease and consequently the... 

To quantify the extraction capacity of carbon dioxide, the partition coefficient of MMA between the water and the C02-phase (m2) is a prerequisite. Since this partition coefficient is not reported in literature, m2 has been measured in a laboratory scale extraction unit at different temperatures and CO2 pressures and has also been predicted using the Peng-Robinson equation of state. 

I 14 Reduction of Residual Monomer in Latex Products Using High-Pressure Carbon Dioxide 14.5.1.2 Partition Coefficients... 

Sie S T, Rijinders G W A 1966 High-pressure gas chromatography and chromatography with supercritical fluids. I. The effect of pressure on partition coefficients in gas-liquid chromatography with carbon dioxide as a carrier gas. Sep Sci 1 459-490... 

Figure 1. PBPK model for dX -trans-veimoic acid and its metabolites. Abbreviations are Dy intravenous dose (mg) Q or P or C, flow rate or partition coefficient or concentration (mg/1) subscripts c (cardiac), f (fat), g (gut), 1 (liver), pi (placenta), r (richly perfused tissues muscle, bone), s (slowly perfused tissues mammary gland, uterus), sk (skin) Dsc diffusivity in stratum comeum (cm%r) k rate constant subscripts b (biliary clearance), CO2 (side chain oxidation to carbon dioxide/hr), ct (cis/trans isomerization), tc (trans/cis isomerization) e (diffusion limited transfer between placenta and embryo, 1/hr) f (fecal excretion/hr) h (hydrolysis of glucuronide/hr) o (oral absorption) r (intestinal absorption) v (intravenous injection) K or V (affinity constant or maximum velocity where mg = apparent Michaelis-Menten glucuronidation constant and mx = apparent Michaelis-Menten oxidation constant). Rounded box indicates the submodels as diagrammed in Figures 2-5. (Reproduced with permission of Mosby-Year Book, Inc. from the American Academy of Dermatology. Clewell, [29].)...

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