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| Registros recuperados: 83 | |
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| Sierra Rayne; Kaya Forest; Ken J. Friesen. |
| We introduce a congener-specific numbering system for the C4 through C8 perfluorinated homologue groups of alkyl sulfonates, carboxylates, telomer alcohols and acids, and their derivatives. Increasing length of the carbon chain beyond C3 leads to a corresponding rapid increase in the number of potential isomers (C4 =4, C5 =8, C6 =17, C7 =39, and C8 =89 congeners). There is a need for clear and unambiguous chemical shorthand to ensure accuracy and consistency in the future perfluorinated alkyl substance (PFA) literature, and to correct previous misconceptions that may have restricted research efforts into developing full-congener PFA analysis. If adopted by the research community, introduction of a numbering system at this relatively early stage of... |
| Tipo: Poster |
Palavras-chave: Chemistry; Earth & Environment. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/1957/version/1 |
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| Sierra Rayne; Kaya Forest. |
| Gas phase constant pressure heat capacities (C~p,gas~) for the C~1~ through C~10~ straight chain alkanes, isobutane, hydrogen atom, hydroxyl and methyl radicals, and water were calculated between 298.15 and 1500 K using various low (semiempirical PM6) through high level (CBS-Q//B3 and G4 composite) theoretical methods. All levels of theory provided good agreement with experimental C~p,gas~ data (<+/-10% deviation) regardless of molecular size. A modest but progressive loss of C~p,gas~ predictive accuracy occurs with increasing molecular size among the n-alkanes. For most compounds at all levels of theory, the highest C~p,gas~ estimation accuracy occurs at elevated temperatures, with decreasing accuracy as the temperature is lowered or raised about... |
| Tipo: Manuscript |
Palavras-chave: Chemistry. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/5024/version/1 |
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| Sierra Rayne; Kaya Forest. |
| New experimental data is available in the literature regarding the octanol-water distribution behavior of representative straight chain perfluoroalkyl carboxylate (PFCA) and sulfonate (PFSA) congeners. The current study provides the first investigation into the predictive ability of various software programs for estimating the corresponding octanol-water partitioning (log P) and distribution (log D) constants of PFCAs and PFSAs. Wide predictive variation was found within and between the various methods. Several programs were able to accurately estimate the log P/D fragmental contributions of a -CF~2~- group for PFCAs, as well as the associated Gibbs free energies for partitioning into octanol from water due to the hydrophobic character of the... |
| Tipo: Manuscript |
Palavras-chave: Chemistry; Earth & Environment. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3282/version/2 |
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| Registros recuperados: 83 | |
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