Hine and Mookerjee

Group contribution and bond contribution methods (Hine and Mookerjee 1975, Meylan and Howard 1991) ... 

DNB (Lyman et al. 1982). Henry s law constant for 1,3,5-TNB was estimated to be 3.08x10 atm-m /mol at 25 °C using a group structural estimation method (Hine and Mookerjee 1975 HSDB 1994). Based on this value, 1,3,5-TNB is essentially nonvolatile (Lyman et al. 1982). This means that it is very unlikely that large amounts of either 1,3-DNB or 1,3,5-TNB would be released into the air from contaminated waters. 

In water, the isomeric cresols may eventually volatilize to the atmosphere, but volatilization is expected to be a slow process. Based on their Flenry s law constants, which range from 1.2x10 to 8.65x10 atm-m /molecule (Gaffney et al. 1987 Hine and Mookerjee 1975), the volatilization half-life from a model river 1 m deep, flowing at 1 m/sec, witha wind velocity of 3 m/sec can be estimated to range from approximately 30 to 41 days (Lyman et al. 1982). 

Hautula 1983 Artiola-Fortuny and Fuller 1982 Boyd 1982 Chao et al. 1983 Daubert and Danner 1985 Freitag et al. 1985 Gaffney et al. 1987 Hansch and Leo 1985 Hine and Mookerjee 1975 OHM/TADS 1989 Riddick et al. 1986 Sax and Lewis 1987 Verschueren 1983 Weast et al. 1988 Windholz et al. 1983 Yalkowsky et al. 1987). Knowledge of some of these properties was required to describe the fate and transport of cresols because adequate experimental data were not available. The database was sufficient to perform the necessary estimates (Lyman et al. 1982). 

Method of Meylan and Howard Meylan and Howard [9] expanded the bond contribution method of Hine and Mookerjee. Based on 345 compounds they derived bond contributions for 59 different bond types. Their method has been validated with an independent set of 74 structurally diverse compounds, obtaining a correlation coefficient of 0.96. Their method also needs correction factors for several structural-substructural features. This method has been implemented into a Henry s law constant program performing AWPC (25°C) estimations from SMILES input [15]. 

The G, values correspond to mono- or polyatomic groups characterized by their aliphatic or aromatic ring attachment. The training set used included data from the Hine and Mookerjee list upgraded with more recent data. Principal component analysis has been employed to propose ]x as the most significant bulk structure... 

Hine and Mookerjee (1975) correlated log KAW, using bond and group contribution approaches with corrections for polar interactions. Data for 292 compounds were used, and the standard deviation was about 0.4 log units or a factor of 2.5 in KAW. Greater accuracy was achieved for the better characterized homologous series, but reliable experimental... 

Suzuki et al. (1992) used principal components analysis to develop a combined connectivity, group contribution method for 229 monofunctional compounds from the Hine and Mookerjee data set. The average error was 0.14 log units. 

The Hine and Mookerjee method has lasted well but is now outdated, and the similar Meylan and Howard correlation supercedes it. This method has the significant advantage of transparency and simplicity thus it is preferred by many over the more complex and less intuitively satisfying connectivity/polarizability methods. If time is available, and espe-... 

Now that solubility and vapor pressure have been defined, consider how a volatile chemical partitions, or distributes itself, between water and air phases at equilibrium. In general, a partition coefficient is the ratio of the concentrations of a chemical in two different phases, such as water and air, under equilibrium conditions. The Henry s law constant, H (or KH), is a partition coefficient usually defined as the ratio of a chemical s concentration in air to its concentration in water at equilibrium. [Occasionally, a Henry s law constant is interpreted in an inverse fashion, as the ratio of a chemical s concentration in water to its concentration in air see, e.g., Stumm and Morgan (1981, p. 179). Note that in that table, KH is equivalent to 1/H as H is defined above ] Values of Henry s law constants are tabulated in a variety of sources (Lyman et al, 1990 Howard, 1989, 1991 Mackay and Shiu, 1981 Hine and Mookerjee, 1975) Table 1-3 lists constants for some common environmental chemicals. When H is not tabulated directly, it can be estimated by dividing the vapor pressure of a chemical at a particular temperature by its aqueous solubility at that temperature. (Think about the simultaneous equilibrium among phases that would occur for a pure chemical in contact with both aqueous and gas phases.) Henry s law constants generally increase with increased temperature, primarily due to the significant temperature dependency of chemical vapor pressures as previously mentioned, solubility is much less affected by the changes in temperature normally found in the environment. 

Russell et al. (1992) conducted a similar study using the same data set from Hine and Mookerjee (1975). They developed a computer-assisted model based on five molecular descriptors which were related to the compound s bulk, lipo-philicity and polarity. They... 

J. Hermans A recent article (Hine and Mookerjee J. Org. Chem. 40, 292, 1975) correlates experimental data which show that the free energy of transfer of hydrocarbons from the vapor to an aqueous solution is near zero, i.e. a molecule such as cyclohexane is equipartioned between vacuum and water. This means that dispersion energies calculated for a model of, say, a protein, in vacuo give in first approximation an adequate description of what are normally called hydrophobic forces. The problem to be faced is to model adequately the interactions between polar groups and solvent and the effect of solvent as a dielectric on the interaction between charges on the modeled molecule. 

P. Kollman Actually, in the Hine and Mookerjee article, the data for cyclohexane and -hexane show them to be 8 times as concentrated in vacuo as in water (cyclohexane) and 74 times as concentrated ( -hexane) in vacuo. Also, a better reference state for our purposes is partitioning between a hydrocarbon solvent (e.g. octanol) and water. The data for octanol-water (see, for example, C. Hanoch in E. J. Ariens (ed.). Drug Design, Academic Press, 1971) lead us to conclude that dispersion attraction also cannot adequately represent hydrophobic forces. 

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