Document Detail


Vapor pressures of the fluorinated telomer alcohols--limitations of estimation methods.
MedLine Citation:
PMID:  15074677     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The influence of the unique, physical properties of poly- and perfluorinated chemicals on vapor pressure was investigated. Vapor pressures of a suite of fluorinated telomer alcohols (FTOHs) (CF3(CF2)nCH2CH2OH, where n = 3, 5, 7, or 9) were measured using the boiling point method and ranged from 144 to 992 Pa. Comparison of experimental and literature values indicate that perfluorocarbons (CF3(CF2)nCF3, where n = 0-6) and fluorinated telomer alcohols have vapor pressures equal to or greater than that of their hydrogen analogues. These chemically counterintuitive results can be explained by the unique geometry of poly- and perfluorinated chemicals--in particular the stiff, helical perfluorinated chain and the significant intramolecular hydrogen bonding of the FTOHs. The majority of models investigated for the estimation of vapor pressure did not compensate for this unique geometry and consistently underpredicted the vapor pressures of the FTOHs. Calculation of partitioning constants using both experimental and estimated vapor pressures indicate that both the Antoine and Modified Grain models, and to a lesser degree the Mackay model, are insufficiently accurate for estimating the vapor pressures of the FTOHs, particularly the longer chain FTOHs. Future models should consider parameters such as geometry, strength, and location of intramolecular hydrogen bonds and otherfunction groups in the molecule in order to improve vapor pressure estimation accuracy. It appears likely that the unique molecular geometry of the FTOHs influences not only their vapor pressure but also other physical properties and hence environmental fate and dissemination.
Authors:
Naomi L Stock; David A Ellis; Lisa Deleebeeck; Derek C G Muir; Scott A Mabury
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Environmental science & technology     Volume:  38     ISSN:  0013-936X     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2004 Mar 
Date Detail:
Created Date:  2004-04-12     Completed Date:  2004-05-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1693-9     Citation Subset:  IM    
Affiliation:
Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 Canada.
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MeSH Terms
Descriptor/Qualifier:
Alcohols / analysis,  chemistry*
Environmental Monitoring
Fluorine Compounds / analysis,  chemistry*
Models, Theoretical*
Reference Values
Volatilization
Chemical
Reg. No./Substance:
0/Alcohols; 0/Fluorine Compounds

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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