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Photolysis of aryl ketones with varying vapor pressures on soil
Author(s) -
Kieatiwong Somchai,
Miller Glenn C.
Publication year - 1992
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620110206
Subject(s) - photodissociation , volatilisation , torr , chemistry , loam , vaporization , soil water , aryl , vapor pressure , analytical chemistry (journal) , water vapor , photochemistry , environmental chemistry , organic chemistry , alkyl , physics , environmental science , soil science , thermodynamics
The photolysis of a series of aryl ketones on air‐dried soil surfaces was examined to establish whether vapor transport has an effect on the rate and extent of photolysis. If vapor transport were significant on light‐exposed soils, then differences in the observed photolysis rate profiles would be expected, with the compounds having higher vapor pressures exhibiting the greatest photolysis. The aryl ketones, including hexanophenone, octanophenone, dodecanophenone, hexadecanophenone, and octadecanophenone, had nearly identical photolysis rates in solution exposed to sunlamps (Λ max 310 nm). The vapor pressures of these five compounds (25 °C) were estimated by a capillary gas chromatographic method and varied from 8.7 × 10 −3 to 8.4 × 10 −8 torr. The compounds were irradiated for 15 d on an air‐dried sandy loam soil surface. The photolysis rate profiles of the four aryl ketones with vapor pressures from 1.3 × 10 −3 torr to 8.4 × 10 −8 torr were identical within experimental error, whereas the most volatile congener, hexanophenone, showed approximately 10% greater loss. Volatilization of hexanophenone appears to have caused the compound to move into the light‐exposed soil surface to a greater extent than the other compounds. These results suggest that vaporization is not important for loss or transport of the compounds with vapor pressures less than 1.3 × 10 −3 torr on air‐dried soils within the 15‐d irradiation.