Atmospheric chemistry of N-methyl perfluorobutane sulfonamidoethanol, C4F9SO2N(CH3)CH2CH2OH: kinetics and mechanism of reaction with OH.
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.
D'eon
Jessica C
JC
Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada
Hurley
Michael D
MD
Wallington
Timothy J
TJ
Mabury
Scott A
SA
D000393:Air Pollutants; D001272:Atmosphere / Q000737:chemistry*; D005466:Fluorocarbons / Q000032:analysis / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D017550:Spectroscopy, Fourier Transform Infrared; D013449:Sulfonamides / Q000032:analysis / Q000737:chemistry*; D013451:Sulfonic Acids / Q000032:analysis / Q000737:chemistry; D014269:Trifluoroacetic Acid / Q000032:analysis / Q000737:chemistry
D000393:Air Pollutants; D005466:Fluorocarbons; C512684:N-methyl perfluorobutane sulfonamidoethanol; D013449:Sulfonamides; D013451:Sulfonic Acids; D017665:Hydroxyl Radical; C033094:perfluorobutyric acid; D014269:Trifluoroacetic Acid; C108042:perfluorobutane