Vapor Pressure of Nine Perfluoroalkyl Substances (PFASs) Determined Using the Knudsen Effusion Method
| Autor: | Jennifer L. Guelfo, Mengke Zhang, Kyle Yamada, Eric M. Suuberg, Stephen Bourguet |
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| Rok vydání: | 2020 |
| Předmět: |
Vapor pressure
General Chemical Engineering Analytical chemistry 02 engineering and technology General Chemistry 010402 general chemistry 01 natural sciences Article 0104 chemical sciences chemistry.chemical_compound 020401 chemical engineering chemistry Effusion Ammonium Sublimation (phase transition) Knudsen number 0204 chemical engineering |
| Zdroj: | J Chem Eng Data |
| ISSN: | 1520-5134 0021-9568 |
| DOI: | 10.1021/acs.jced.9b00922 |
| Popis: | Sublimation vapor pressures of nine pure perfluoroalkyl substances, including Ammonium perfluoro(2-methyl-3-oxahexanoate) (GenX), 1H,1H,2H,2H-Perfluoro-1-decanol (8:2 FTOH), 1H,1H,2H,2H-Perfluoro-1-dodecanol (10:2 FTOH) and C6 to C11 perfluorocarboxylic acids (PFCAs), were measured using the Knudsen technique at near ambient temperatures. Melting temperatures and fusion enthalpies of these compounds were also measured using differential scanning calorimetry. The vapor pressure of GenX ammonium salt is comparable to that of the much higher molecular weight perfluoroundecanoic acid. GenX ammonium salt also did not show actual melting behavior but instead decomposed at around 470 K. The measured near ambient temperature sublimation vapor pressures of the PFCAs and FTOHs were compared with some earlier reported liquid phase vapor pressures obtained at higher temperatures, and reasonable agreement exists between the data obtained in the different studies. The sublimation enthalpies of the PFCAs indicate that the contribution to the sublimation enthalpy of the CF(2) group in the alkyl chain is comparable to that of the CH(2) group in the corresponding non-fluorinated analogues, even though the PFCAs show consistently higher vapor pressures than do the corresponding carbon number alkanoic acids. |
| Databáze: | OpenAIRE |
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