Liquid-gas partition coefficients

Baner L and Piringer O G, 1994, Liquid/gas partition coefficients of aroma compounds and n-alkanes between aqueous ethanol mixtures and nitrogen. J. Chem. Eng. Data 1994, 39 (2), 341-348 and references given there. 

The aqueous solubilities of several volatile anaesthetics can be related to the osmolarity of the solution. The inverse relationship between solubility (expressed as the liquid/gas partition coefficient) of those anaesthetics and the osmolarity is shown in Table 3.4. 

Table 3.4 Liquid/gas partition coefficients of anaesthetics in four aqueous solutions at 37°C°...

Table I. E erimental Infinite-Dilution Liquid-Gas Partition Coefficients of Indicated Solutes with Listed Volume Fractions of Squalane (SQ) +...

Comparison of the particle/gas partition coefficient (Kp) among compound classes when normalized to liquid-phase vapor pressure (PSL). Filled and open triangles = alkanes, filled and open circles = PAHs from Liang and Pankow (1996) or Pankow et al. (1994). Figure from Liang and Pankow (1996). 

The vapour-liquid distribution (partition) coefficient, K, is defined as the ratio of the equilibrium concentration of the solute in the sample (CJ to that in the gas phase (C ) ... 

The oil solubility of an anaesthetic is of interest, not only because it governs the passage of the anaesthetic into and out of the fat depots of the body, but also because there is a well-established correlation between anaesthetic potency and oil solubility. Figure 2.10 shows a linear inverse relationship between log narcotic concentration and log solubility in oleyl alcohol for a series of common anaesthetic gases. The ordinate of the graph represents the minimum alveolar concentration (MAC), which is that concentration of anaesthetic at which 50% of the patients cease to move in response to a stimulus. The abscissa shows the solubility expressed in terms of the oil/gas partition coefficient. Partition coefficients are widely used to express solubility and are the ratios of the concentration of the gas in the two phases in equilibrium at a given temperature. When, as in this case, one of the phases is the gas itself, the partition coefficient expressed as the liquid/gas (note the order of the phases) concentration ratio is equal to the... 

Katsanos, N.A. Kapolos, J. Diffusion coefficients of gases in liquids and partition coefficients in gas-liquid interphases by reversed-flow gas chromatography. Anal. 

But what about the more volatile organic compounds. Even for these compounds there are differences in the degree to which they are absorbable, and the determining factor is the compound s blood gas partition coefficient. To understand how the blood gas partition coefficient governs absorption, consider a vapor enclosed in a cocktail shaker with a bit of water. After the cocktail is shaken, the vapor can partition either into the water or it can primarily remain in the atmosphere within the shaker. In this case, chemicals that remain in the shaker s atmosphere have low blood gas partition coefficients, whereas chemicals found predominantly in the liquid have high values for the coefficient. These tendencies dramatically influence the capacity for absorption, because low values of the blood gas coefficient are indicative of low rates of absorption, whereas elevated coefficient values predict much higher rates of absorption across the lung epithelium. 

Elution volume, exclusion chromatography Flow rate, column Gas/liquid volume ratio Inner column volume Interstitial (outer) volume Kovats retention indices Matrix volume Net retention volume Obstruction factor Packing uniformity factor Particle diameter Partition coefficient Partition ratio Peak asymmetry factor Peak resolution Plate height Plate number Porosity, column Pressure, column inlet Presure, column outlet Pressure drop... 

Where FCl is the solute gas-liquid partition coefficient, r is the tendency of the solvent to interact through k- and n-electron pairs (Lewis basicity), s the contribution from dipole-dipole and dipole-induced dipole interactions (in molecular solvents), a is the hydrogen bond basicity of the solvent, b is its hydrogen bond acidity and I is how well the solvent will separate members of a homologous series, with contributions from solvent cavity formation and dispersion interactions. 

The P scale of solvent polarity is based on a combination of gas-liquid partition coefficients reported by Rohrschneider [43]. 

The effectiveness of an odorant depends on the partition coefficients and the solubility. Vapor-liquid equilibria data for sulfur compounds in liquified natural gas are available [745,944]. 

The net retention volume and the specific retention volume, defined in Table 1.1, are important parameters for determining physicochemical constants from gas chromatographic data [9,10,32]. The free energy, enthalpy, and. entropy of nixing or solution, and the infinite dilution solute activity coefficients can be determined from retention measurements. Measurements are usually made at infinite dilution (Henry s law region) in which the value of the activity coefficient (also the gas-liquid partition coefficient) can be assumed to have a constant value. At infinite dilution the solute molecules are not sufficiently close to exert any mutual attractions, and the environment of each may be considered to consist entirely of solvent molecules. The activity... 

The gas-liquid partition coefficient is evaluated froa the specific retention volune using equation (1.6)... 

The gas-liquid partition coefficient is relate to the capacity factor by equation (1.11). 

In gas chromatography the value of the partition coefficient d ends only on the type of stationary phase and the column temperature. It is independent of column type and instrumental parameters. The proportionality factor in equation (l.ll) is called the phase ratio and is equal to the ratio of the volume of the gas (Vg) and liquid (V ) phases in the column. For gas-solid (adsorption) chromatography the phase ratio is given by the volume of the gas phase divided by the surface area of the stationary phase. 

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