Vapor pressure of compound

The constants A, B, and C for many compounds are in the data bank of some simulation design packages. Alternatively, these are found in texts such as Reid et al [2]. Equation 2-10 is only applicable for pressures with ranges from 10 to 1500 mmHg. Reid et al [2]. and Beaton and Hewitt [3] have discussed other methods in estimating vapor pressure of compounds but none appears to offer any specific advantage. 

The significant vapor pressure of compound 26 allowed rapid mass transport of the precursor at 22 °G and the facile decomposition pathway resulted in film growth at temperatures as low as 200 °G. Epitaxial GaN films were deposited from 26 at 650 °G via LPGVD. " The growth rate of the GaN films deposited was 800 A min Despite these excellent growth properties, the high reactivity of 26 necessitates careful manipulation of the neat product, as a vigorous exothermic decomposition can result. 

The last term is only used for calculating the vapor pressure of compounds that are solids and would be neglected with compounds that are liquids at ambient temperature. Vapor pressures calculated at 25°C for some compounds listed in Table 2.2 are compiled in Table 2.4. The calculated values are well within the range of the recommended experimental values. It should be emphasized that this relation was developed for relatively nonpolar compounds and is not suited to more polar compounds such as phenols. Other procedures for predicting vapor pressure have been oulined. In addition, procedures are available for calculating boiling points from molecular properties. 

Figure 16-16. Vapor pressures of four typical volatile organic compounds = vapor pressure of compound (mm Hg), Tcm = condensaftlon temperature ( F). U.S. EPA Handbook, 1991)...

Jordan, T. E. "Vapor Pressure of Organic Compounds," Interscience, New York, 1954. 

Compilation of vapor pressures of organic and related compounds to one atmosphere. 

Table 5.8 Vapor Pressures of Various Inorganic Compounds 5.31...

Table 5.9 Vapor Pressures of Various Organic Compounds 5.39...

Numerous mathematical formulas relating the temperature and pressure of the gas phase in equilibrium with the condensed phase have been proposed. The Antoine equation (Eq. 1) gives good correlation with experimental values. Equation 2 is simpler and is often suitable over restricted temperature ranges. In these equations, and the derived differential coefficients for use in the Hag-genmacher and Clausius-Clapeyron equations, the p term is the vapor pressure of the compound in pounds per square inch (psi), the t term is the temperature in degrees Celsius, and the T term is the absolute temperature in kelvins (r°C -I- 273.15). 

Ammonium bicarbonate, also known as ammonium hydrogen carbonate or ammonium acid carbonate, is easily formed. However, it decomposes below its melting point, dissociating into ammonia, carbon dioxide, and water. If this process is carefully controlled, these compounds condense to reform ammonium bicarbonate. The vapor pressures of dry ammonium bicarbonate are shown below (7). (To convert kPa to mm Hg, multiply by 7.5.)... 

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