Pressure Henry’s law

Shiu, W.-Y., Mackay, D. (1986) A critical review of aqueous solubilities, vapor pressures, Henry s law constants, and octanol-water partition coefficients of the polychlorinated biphenyls. J. Phys. Chem. Ref. Data 15, 911-929. 

Vapor pressure exceeds atmospheric pressure, Henry s law constant H/(Pa-m3/mol) = 101325 Pa/Cs mol/m3. 

TABLE 4.1.1.19.1 Reported vapor pressures and Henry s law constants of acenaphthlyene at various temperatures and the coefficients for the vapor pressure equations Vapor pressure Henry s law constant ... 

Hinckley, D.A. (1989) Vapor Pressures, Henry s Law Constants and Air-Sea Gas Exchange of Selected Organochlorine Pollutants. Ph.D. Thesis, University of South Carolina. 

Predicting sorption coefficients and hence the mobility of organic pollutants in aqueous-solid systems requires complete knowledge and analysis of various physical and chemical properties of such pollutants. This includes properties such as solubility, equilibrium vapor pressure, Henry s law constant, partition coefficient, as well as pKa and pKb values. Such properties can initially help determine the sorption-desorption behavior of organic pollutants once they are released, directly and/or indirectly, to the aqueous environment and then are in direct contact with solid phases. The following sections briefly summarize these properties. 

A few gases may be involved in some enzyme reactions, e.g., C02 and 02 as used by carbonic anhydrase and produced by catalase, respectively. If the presence of such dissolved gases affects rates and equilibria at ordinary pressure, their importance will increase at higher pressure. Henry s law says that the partial pressure of a gas above a solution is proportional to its mole fraction in the solution. At high pressure it is more correct to speak of the fugacity / of a gas, instead of partial pressure, in the same sense that one uses activity instead of concentration in solution calculations. In dilute solutions, the fugacity of the dissolved gas is given by... 

T is temperature, P is pressure, and / is the fugacity of the component. In Equation 3 subscript k refers to each component of the system. In the present discussion the fugacity 42) is employed in preference to the chemical potential 21). Earlier in the history of the petroleum industry, Raoult s 55) and Dalton s laws were applied to equilibrium at pressures considerably above that of the atmosphere. These relationships, which assume perfect gas laws and additive volumes in the gas phase and zero volume for the liquid phase, prove to be of practical utility only at low pressures. Henry s law was found to be a useful approximation only for gases which were of low solubility and at reduced pressures less than unity. 

Henry s law constant Hx = Hypc where pc = gas-phase pressure Henry s law constant Hy = Xnn T/Xnn water (mole fraction ratio for compound i) ionic strength... 

Water at OC Organic solvents Partition coefficients Vapor pressure Henry s law constant Autoignition temperatture... 

Table 23.1 Water solubilities, vapor pressures, Henry s Law constants, and pKa values of currently used triazine herbicides...

Vapor pressure Henry s law No data No data No data No data 760 mm at -87.4°C... 

Reported aqueous solubilities, vapor pressures, Henry s law constants and octanol-air partition coefficients of 2,2, 4,5,5 -pentachlorobiphenyl (PCB-101) at various temperatures and the reported empirical temperature dependence equations... 

Explicit predictions for adsorption parameters can be obtained by application of statistical mechanics to detailed models for the adsorbed phase. Many such models have been developed (cf. Young Crowell, 1962 Ross Olivier, 1964), but a model suitable for a given application cannot in general be chosen a priori. A simple example, used by Podosek, Bernatowicz, and Kramer (1981b) for fitting very-low-pressure (Henry s law region) Xe and Kr adsorption on shales (Figure 2.4) is... 

Vapor pressure Henry s law constants Autoi gni ti on temperature FIashpoi nt FIammabi1i ty limits... 

---