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Effect of vapor pressure

The choice of the solvent also has a profound influence on the observed sonochemistry. The effect of vapor pressure has already been mentioned. Other Hquid properties, such as surface tension and viscosity, wiU alter the threshold of cavitation, but this is generaUy a minor concern. The chemical reactivity of the solvent is often much more important. No solvent is inert under the high temperature conditions of cavitation (50). One may minimize this problem, however, by using robust solvents that have low vapor pressures so as to minimize their concentration in the vapor phase of the cavitation event. Alternatively, one may wish to take advantage of such secondary reactions, for example, by using halocarbons for sonochemical halogenations. With ultrasonic irradiations in water, the observed aqueous sonochemistry is dominated by secondary reactions of OH- and H- formed from the sonolysis of water vapor in the cavitation zone (51—53). [Pg.262]

Effects of vapor pressure lowering. Because a nonvolatile solute lowers the vepor pressure of a solvent, the boiling point of a solution will be higher and the freezing point lower than the corresponding values for the pure solvent Water solutions freeze below 0°C at point A and boil above 100°C at point B. [Pg.270]

An increase in temperature at constant pressure, on one hand, leads to a decrease in solvent density, which would lower the solubility. On the other hand, an increase in temperature results in an increase in vapor pressure of naphthalene. At high pressures, the density dependence on temperature is small compared with the effect of vapor pressure, which results in an increased solubility. At lower pressures, the density effect dominates when increasing the temperatures, resulting in a decrease in solubility. [Pg.448]

The solubility data for naphthalene in ethylene and in CO2 are consistent with the data in Figure 3. The proper way to make the comparison is to use the enhancement factor instead of the solubility. The enhancement factor equals y2P/P2 which is simply the actual solubility divided by the solubility in an ideal gas. The enhancement factor removes the effect of vapor pressure which is useful for comparing fluids at constant reduced temperature but at different actual temperatures. In terms of the fugacity coefficient of the solute, 2, the enhancement factor is given by... [Pg.47]

Harnor, K. J., Perkins, A. C., Wastie, M., et al. (1993), Effect of vapor pressure on the deposition pattern from solution phase metered dose inhalers, Int. J. Pharm., 95, 111-116. [Pg.717]

ABSTRACT In the frame of calcium sulfate p-hcmihydratc hydration kinetical studies, a simple experimental set up has been developed to determine the rate of hydration for different species of incompletely hydrated plaster specimens. This apparatus may also be used to determine widi accuracy the amount of gypsum contained in plaster rocks, and acquire simultaneously quantitative analysis for six specimens. The apparatus is described, and the effect of vapor pressure is studied. [Pg.57]

Konno T, Kinuno K (1989) Physical and chemical changes of medicinal in mixtures with adsorbents in the solid state II. Application of reduced pressure treatment for the improvement of dissolution of flufenamic acid. Chem Pharm Bull 37 2481-2484 Konno T, Kinuno K, Kataoka K (1986) Physical and chemical changes of medicinals in mixtures with adsorbents in the solid state I. Effect of vapor pressure of the medicinals on changes in crystalline properties. Chem Pharm Bull 34 301-307 Kovafiic B, Vrecer F, Planinsek O (2011) Solid dispersions of carvedilol with porous silica. Chem Pharm Bull 59(4) 427-433... [Pg.689]

Conde,L.F., Kramer, P.J. The effect of vapor pressure deficit and diffusion resistance in Opuntia compressa. Can. J. Bot. 53,2923-2926 (1975)... [Pg.181]

Nearly all of the analysis of mesoporosity starts with the Kelvin-Cohan [14] formulation. Foster [15] proposed the Kelvin equation for the effect of vapor pressure on capillary rise but did not anticipate its use for very small capillaries where the adsorbate thickness is a significant geometrical perturbation. Cohan formulation subtracts the adsorbate film thickness from the radius of the pore to yield the modified Kelvin equation... [Pg.187]

Vapor pressure lowering occurs at all temperatures. We can see the effect of vapor pressure lowering over a range of temperatures by comparing the phase diagrams for a pure solvent and for a solution containing a nonvolatile solute ... [Pg.574]

Empirical. The effect of vapor pressure (or percentage butanes) is greater than computations indicate. [Pg.839]


See other pages where Effect of vapor pressure is mentioned: [Pg.25]    [Pg.271]    [Pg.54]    [Pg.38]    [Pg.250]    [Pg.96]    [Pg.226]    [Pg.49]    [Pg.450]    [Pg.19]    [Pg.88]    [Pg.132]    [Pg.313]   
See also in sourсe #XX -- [ Pg.52 ]




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