Application of the surface area approach to the correlation and estimation of aqueous solubility and vapor pressure. Alkyl aromatic hydrocarbons

Abstract

A group surface area approach is developed and applied to the estimation of the free energy changes for the following processes; (I) pure (supercooled) liquid to aqueous solution ( °), (II) pure (supercooled) liquid to gas ( ß]°), and (III) gas to aqueous solution ( ß3°).The corresponding estimates of eoiubWty (pure llquld/solutlon and gas/sdutlon) and vapor pressure at 298 K are easily made. The standard error of the estimate In the worst case (gas to solution) Is only 1.1 kJ mor1. Analysis of the surface area models shows that the single variable total surface area, TSA, can be used to estimate the pure (supercooled) liquid to aqueous solution free energy change, ÁG1°, with a standard error of 1.1 kJ/md. This apparent simplicity Is due to compensating changes In AG2°a nd G3°. For the latter two steps a partitioning of the TSA Into group areas Is required. Within the context of the surface area model, this Is attributed to significant differences In surface area coefficients for the aliphatic and aromatic hydrogens. The particular choice of group surface area terms In the final selected model shows good additivity as measured by application of the method to compounds not Included In the study.

Selecting reliable physicochemical properties of perfluoroalkyl and polyfluoroalkyl substances (PFASs) based on molecular descriptors

“…QSPR studies are based on the correlation between the experimental values and different molecular descriptors such as the number of specific atoms, molecular volume, molecular surface area, molecular connectivity indexes and relative retention time. Among the most commonly used molecular descriptors are the number of specific atoms, molar volume and total surface area (Yue and Li, 2013) which are related to the chemical's hydrophobicity, aqueous solubility and octanol/water partitioning (Amidon and Anik, 1981;Gobas, 1991;Mailhot and Peters, 1988). This paper aims to: (i) review available experimental and estimated data for key basic physicochemical properties of PFASs (vapor pressure (P L ), aqueous solubility (S L ), air/water partition coefficient (K AW ), octanol/water partition coefficient (K OW ) and octanol/air partition coefficient (K OA )).…”

Estimations of vapor pressure and activity coefficients in water and octanol for selected aromatic chemicals at 25°C

“…Various quantitative structure-property relationship methods have been developed to estimate these properties, including the well-established UNIFAC and AQUAFAC predictions of aqueous and nonaqueous solubilities [2][3][4][5][6][7][8][9][10][11][12][13][14] and other group contribution methods [15][16][17][18][19] for the estimation of S W . Group contribution methods [20][21][22] are also used to calculate P S . Leo's fragment constant method [23] can be applied to calculate K OW .…”

Volatilization of benzene and eight alkyl-substituted benzene compounds from water

“…Water-solubility values from these four studies, references cited in these studies, and water-solubility values from Amidon and Anik (1981) and Mackay and Shiu (1981) were evaluated for benzene through n-hexylbenzene. Values differing by more than three standard deviations of the means were excluded as outliers.…”

“…Water-solubility values for n-heptylbenzene and noctylbenzene were estimated using correlations of solubility with molecular surface area (Amidon and Anik, 1981) and molar volume (McAuliffe, 1966), a correlation of the reciprocal of the solubility with normal boiling temperature (Wasik and others, 1982), and a correlation of the activity coefficient as a function of the number of carbon atoms in the molecule (Tsonopoulos and Prausnitz, 1971). It has been reported (Mackay and Shiu, 1975) that the activity coefficient defined by the Raoult's law convention is the reciprocal of the mole fraction solubility for dilute aqueous solutions of organic compounds.…”

“…Molecular surface areas for benzene through nbutylbenzene were obtained from Amidon and Anik (1981). Areas for n-pentylbenzene through n-octylbenzene were calculated using an incremental area of 0.318 nm2 for each additional CH2 group (Valvani and others, 1976).…”