| Volatilization | A pKa of 4.8(1) indicates heptanoic acid will exist almost entirely in the anion form at pH values of 5 to 9 and therefore volatilization from water surfaces and moist soil is not expected to be an important fate process(2). Heptanoic acid is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.07X10-2 mm Hg(3).
Literature: (1) Serjeant EP, Dempsey B; Ionisation Constants of Organic Acids in Aqueous Solution IUPAC Chemical Data Series No.23 NY, NY: Pergamon Press. p. 287 (1979) (2) Doucette WJ; pp. 141-188 in Handbook of Property Estimation Methods for Chemicals. Boethling RS, Mackay D, eds. Boca Raton, FL: Lewis Publ (2000) (3) Daubert TE, Danner RP; Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, DC: Taylor and Francis (1989) |
| Soil Adsorption | The Koc of undissociated heptanoic acid is estimated as 490(SRC), using a log Kow of 2.42(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that undissociated heptanoic acid is expected to have moderate mobility in soil. The pKa of heptanoic acid is 4.8(4), indicating that this compound will exist almost entirely in anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(5).
Literature: (1) Sangster J; LOGKOW Databank, Sangster Res Lab, Montreal Quebec, Canada (1994) (2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 4-9 (1990) (3) Swann RL et al; Res Rev 85: 17-28 (1983) (4) Serjeant EP, Dempsey B; Ionisation Constants of Organic Acids in Aqueous Solution IUPAC Chemical Data Series No.23 NY, NY: Pergamon Press. p. 287 (1979) (5) Doucette WJ; pp. 141-188 in Handbook of Property Estimation Methods for Chemicals. Boethling RS, Mackay D, eds. Boca Raton, FL: Lewis Publ (2000) |
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