Atmospheric Chemistry ofN-methyl Perfluorobutane Sulfonamidoethanol, C₄F₉SO₂N(CH₃)CH₂CH₂OH:  Kinetics and Mechanism of Reaction with OH

Abstract

Relative rate methods were used to measure the gas-phase reaction of N-methyl perfluorobutane sulfonamidoethanol (NMeFBSE) with OH radicals, giving k(OH + NMeFBSE) = (5.8 +/- 0.8) x 10(-12) cm3 molecule(-1) s(-1) in 750 Torr of air diluent at 296 K. The atmospheric lifetime of NMeFBSE is determined by reaction with OH radicals and is approximately 2 days. Degradation products were identified by in situ FTIR spectroscopy and offline GC-MS and LC-MS/MS analysis. The primary carbonyl product C4F9SO2N(CH3)CH2CHO, N-methyl perfluorobutane sulfonamide (C4F9SO2NH(CH3)), perfluorobutanoic acid (C3F7C(O)OH), perfluoropropanoic acid (C2F5C(O)OH), trifluoroacetic acid (CF3C(O)OH), carbonyl fluoride (COF2), and perfluorobutane sulfonic acid (C4F9SO3H) were identified as products. A mechanism involving the addition of OH to the sulfone double bond was proposed to explain the production of perfluorobutane sulfonic acid and perfluorinated carboxylic acids in yields of 1 and 10%, respectively. The gas-phase N-dealkylation product, N-methyl perfluorobutane sulfonamide (NMeFBSA), has an atmospheric lifetime (>20 days) which is much longer than that of the parent compound, NMeFBSE. Accordingly,the production of NMeFBSA exposes a mechanism by which NMeFBSE may contribute to the burden of perfluorinated contamination in remote locations despite its relatively short atmospheric lifetime. Using the atmospheric fate of NMeFBSE as a guide, it appears that anthropogenic production of N-methyl perfluorooctane sulfonamidoethanol (NMeFOSE) contributes to the ubiquity of perfluoroalkyl sulfonate and carboxylate compounds in the environment.

Neutral poly- and perfluoroalkyl substances in air and seawater of the North Sea

“…In principle, gaseous FASEs likely react with OH radicals resulting in various products, including FASAs. It was reported that the atmospheric lifetime of MeFBSE is approximately 2 days, and MeFBSA has an atmospheric lifetime of >20 days (D'Eon et al 2006). In this work, we did not find a significant change of composition between FASAs and FASEs as compared to the data determined in an urban area of Hamburg (Germany) (Dreyer and Ebinghaus 2009).…”

“…Because of their slow reaction process with hydroxyl radicals, atmospheric lifetimes were estimated~10−20 days for FTOH and~20−50 days for perfluoroalkane sulphonamide (FASA) in smog chamber studies (Ellis et al 2004;Martin et al 2006) and atmospheric residence time of more than 50 days for FTOHs in field studies (Piekarz et al 2007), which suggest they are subject to regional and long-range atmospheric transport, e.g., the Arctic and Antarctic (Dreyer et al 2009b;Stock et al 2007;Jahnke et al 2007b). Degradation of these precursors may account for the presence of PFOA and PFOS in remote regions (Andersen et al 2005;D'Eon et al 2006;Ellis et al 2004;Martin et al 2006;Zhao et al 2012). Apart from atmospheric reaction, degradation of FTOHs and FTSEs/FOSAs in the aquatic phase can be an additional source for PFCAs and PFSAs, especially in the remote oceans (Armitage et al 2006(Armitage et al , 2009Cousins et al 2011).…”

Spatial distribution of per- and polyfluoroalkyl compounds in coastal waters from the East to South China Sea

“…The dominance of PFOA and PFOS in coastal waters might indicate that the contamination originated from WWTP effluents where they were found to be the predominant PFCs, such as in Denmark (Bossi et al, 2008), Georgia and Kentucky (USA) (Loganathan et al, 2007), Germany (Ahrens et al, 2009c), Canada (Furdui et al, 2008), Austria (Clara et al, 2008) and Catalonia (Sánchez-Avila et al, 2010). In our study, the concentration of PFBS (average of 302 pg/L) was about one order of magnitude higher than that of PFOS (average of 24 pg/L), This can be partly attributed to the increasing production of N-methyl perfluorobutane sulfonamidoethanol (MeFBSE) and related products with four perfluorinated carbons, which was introduced after the voluntary phase-out of POSF by the 3M Company in 2000 (D'Eon et al, 2006). Our results indicate that the emissions of PFOS into the aqueous environment decreased whereas the C 4 -based compounds PFBS became the predominant PFSA.…”

“…In contrast, PFOS is the predominant compound in wildlife (Kannan et al, 2001a,b), which can be explained by its higher bioaccumulation potential, whereas PFOA has a higher water solubility (Brooke et al, 2004) and lower sorption potential to sediment . On the other hand, the PFOA concentrations are usually higher in open-ocean waters compared to PFOS, which can be explained by different amount of discharge into the aqueous environment, different sources Paul et al, 2009), different degradation process of the precursors D'Eon et al, 2006) and different physico-chemical characteristics.…”

Perfluoroalkyl and polyfluoroalkyl substances in the lower atmosphere and surface waters of the Chinese Bohai Sea, Yellow Sea, and Yangtze River estuary

“…The mean concentration of the ∑ FASAs was 4.4 ± 2.6 pg/m 3 , which was significantly higher than that of the ∑ FASEs (mean 0.61 ± 0.39 pg/m 3 ). FASAs last longer in air than FASEs and have the potential to be transported across longer distances than FASEs (D'Eon et al, 2006). MeFBSA and MeFBSE were detected in all samples, and showed higher concentrations than those of MeFOSA and Me/EtFOSE, which may be attributed to the replacement of C 8 -PFASs (Lai et al, 2016).…”