Vapor Pressure of Glycerol

Recently, Ray et al. (1991b) reported the vapor pressure of glycerol at 298 K to be 0.0223 Pa. Equation (109) yields a value of 0.0138 Pa at that temperature. It appears that the correlation of Tang and Munkelwitz underpredicts the vapor pressure near room temperature because of the procedure used to determine the constants in the equation. The approximation written as Eq. (110) is not sufficiently accurate to permit its application over a wide range of temperatures. As shown by Fuller et al. (1966), data for numerous low-molecular-weight binary systems agree with the approximation that Dij is proportional to An exponent between 1.75 and 2 would be a better... 

SIMS. Secondary Ion Mass Spectrometry is particularly suited for ionization of nonvolatile, polar, and thermally labile molecules. Liquid SIMS, using liquid glycerol matrices, is best done in the differentially-pumped external ion source, because matrix effects and the high vapor pressure of glycerol make liquid SIMS unsuitable for single cell low-pressure FTMS. 

Comment The calculation assumes that glycerol is nonvolatile. At 1 atm, glycerol boils at 290.0°C, so the vapor pressure of glycerol at 50°C is so low it can be neglected. 

Table 7.205 Vapor Pressure of Glycerol-Water Solutions (23)...

Zil berman-Granovskaya, A. A. (1940) Measurement of small vapor pressures. I. Vapor pressures of naphthalene, camphor and glycerol. J. Phys. Chem. (U.S.S.R.) 14, 759-767. 

Chylek et al. (1983) showed that, by comparing experimental resonance spectra with spectra computed using Mie theory, the size and refractive index of a microsphere can be determined to about one part in 10. Numerous investigators have used resonance spectra to determine the optical properties of microspheres since Ashkin and Dziedzic observed resonances. A recent example is the droplet evaporation study of Tang and Munkelwitz (1991), who measured the vapor pressures of the low-volatility species dioctyl phthalate (DOP), glycerol, oleic acid, and methanesulfonic acid (MSA). This... 

The title of the graph must be explicit but not obvious. For example, a log-log plot of temperature versus the vapor pressure of pure glycerol should not be entitled Log-Log Plot of Temperature versus Vapor Pressure for Pure Glycerol. A much better title, although still somewhat obvious, would be Effect of Temperature on Vapor Pressure of Pure Glycerol. ... 

Plwsical Properties The physical properties that are important in solvent drying are the same as those for an aqueous system. The vapor pressure of a solvent is the most important property since it provides the thermodynamic driving force for drying. Acetone (BP 57 C), for example, can be removed from a solid at atmospheric pressure readily by boiling, but glycerol (BP 200°C) will dry only very slowly. Like water, a solvent may become bound to the solid and have a lower vapor pressure. This effect should be considered when one is designing a solvent-drying process. 

The freezing points of three glycerol solutions in water are — 1.918 C for 1.0 molal, — 3.932 C for 2.0 molal and — 10.68 for 5.0 molal. Determine the activities and activity coefficients of the water in these solutions on the basis of the usual standard state, and consider the departure from Raoult s law. The vapor pressure of pure (supercooled) water at — 1.92 C is 3.980 mm. what would be the aqueous vapor pressure of the 1.0 molal glycerol solution at this temperature ... 

Soil chemists more commonly measure the retention of polar liquids such as ethylene glycol or glycerol by soils. The basic procedure involves applying excess and then removing all but a monolayer from the mineral surfaces. The excess is removed under vacuum in the presence of a desiccant, to eliminate competition with H2O for retention sites. Some workers advocate a glycol-CaCU mixture to maintain a relatively constant vapor pressure of glycol in the evacuated system, and hence to provide a more reproducible endpoint. 

Problem Find the vapor pressure lowering, AR when 10.0 mL of glycerol (CjHgOj) is added to 500. mL of water at 50.°C. At this temperature, the vapor pressure of pure water is 92.5 torr and its density is 0.988 g/mL. The density of glycerol is 1.26 g/mL. Plan To calculate AP, we use Equation 13.10. We are given the vapor pressure of pure water (/h o = 92.5 torr), so we just need the mole fraction of glycerol, X... 

Two donor-acceptor systems were examined, with Coumarin 1 (Cl) and 9-aminoacridine (9AA) as donors and Rhodamine 6G (R6G) as the acceptor. Initial experiments were performed to compare the amount of transfer observed in bulk solution and in particles made of the same material. Glycerol was chosen as the solvent, mainly because of its low vapor pressure and high viscosity. The low vapor pressure was necessary so that particles would be relatively stable in size, and the high viscosity ensures that the excited donor is essentially stationary for the lifetime of the excited state. The concentrations used were chosen to minimize donor reabsorption and to make the extinction of the donor considerably larger than the extinction of the acceptor at the excitation wavelength. Excitation wavelengths of either 365 or 387 nm were used in the experiments. Concentration ratios, donor to acceptor, of 10 1 and... 

White orthorhombic crystals, produced in the form of pellets, lumps, sticks, beads, chips, flakes or solutions hygroscopic very corrosive rapidly absorbs CO2 and water from the air density 2.13 g/cm melts at 323°C vaporizes at 1388°C vapor pressure 1 torr at 739°C and 5 torr at 843°C very soluble in water (110 g/lOOmL at room temperature), generating heat on dissolution aqueous solutions highly alkaline, pH of 0.5% solution about 13 and 0.05% solution about 12 soluble in methanol, ethanol and glycerol (23.8 g/100 mL methanol and 13.9 g/100 mL ethanol at ambient temperatures.)... 

Matrix Considerations Non-volatile and thermally fragile molecular samples are dissolved in a liquid matrix for introduction into the spectrometer to perform FABMS measurements. The properties generally Imposed upon the matrix include ability to dissolve samples and possession of low vapor pressure to extend life time in the vacuum environment. Sample life time should be several minutes to be able to optimize the spectral signal and make several spectral runs. Many organic liquids that satisfy these requirements have been used to obtain FAB data by several investigators (7, 31, 32). Two of the more often used matrices are glycerol and thioglycerol In addition, a liquid metal matrix was used to float the sample to obtain FABMS spectra (33). 

T is the Kelvin temperature and "a" is the area in cm2. At 20°C the vapor pressure is 1.75 x 10-l torr and the evaporation rate is 2.9 x 10 7g/sec from a sample whose area is 5mm2. At this rate the glycerol would last 14 minutes and at 40°C only 5 minutes. At 100°C it would disappear in about 2 seconds. This illustrates the importance of maintaining a cooled target and source below 30°C. Heating transfer tubes and analyzers should be avoided. Data can be taken at higher temperatures, but the short lifetimes require excellent preparation and impose insufficient time for optimization. 

Fast atom bombardment (FAB) uses high-energy xenon or argon atoms (6-10 keV) to bombard samples dissolved in a liquid of low vapor pressure (e.g., glycerol). The matrix protects the sample from excessive radiation damage. A related method, liquid secondary... 

The method can be applied for saturated fatty acids, unsaturated fatty acids, fatty esters, fatty alcohols and acyl-glycerols. The regression is based on 1200 data points. The absolute deviation in predicting vapor pressure is 6.82%. Another advantage of Eq. (14.1) is the capability of predicting the VLE of mixtures of fatty acids and esters by using the UNIFAC model for liquid activity. The comparison with experimental data shows good accuracy not achieved by other methods [40]. 

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