Atmospheric chemistry of 4:2 fluorotelomer iodide (n-C4F9CH2CH2I): kinetics and products of photolysis and reaction with OH radicals and Cl atoms.
Relative rate techniques were used to study the title reactions and determine rate constants of k(Cl + C(4)F(9)CH(2)CH(2)I) = (1.25 +/- 0.15) x 10(-12) and k(OH + C(4)F(9)CH(2)CH(2)I) = (1.2 +/- 0.6) x 10(-12) cm(3) molecule(-1) s(-1) in 700 Torr total pressure at 295 K. The fluorotelomer aldehyde (C(4)F(9)CH(2)CHO), perfluorinated aldehyde (C(4)F(9)CHO), fluorotelomer acid (C(4)F(9)CH(2)C(O)OH), fluorotelomer peracid (C(4)F(9)CH(2)C(O)OOH), and several perfluorocarboxylic acids were detected by in situ FTIR spectroscopy and offline analysis as products of the chlorine atom initiated oxidation of C(4)F(9)CH(2)CH(2)I in air. The UV-visible spectra of C(4)F(9)CH(2)CH(2)I and C(2)H(5)Cl were recorded over the range of 200-400 nm. Photolysis of C(4)F(9)CH(2)CH(2)I gives C(4)F(9)CH(2)CHO as the major observed product. By assumption of a photolysis quantum yield of unity, it was calculated that the atmospheric lifetime of C(4)F(9)CH(2)CH(2)I is determined by photolysis and is a few days. A mechanism for the atmospheric oxidation of fluorotelomer iodides, (C(x)F(2x+1)CH(2)CH(2)I, where x = 2, 4, 6,...) is proposed. Atmospheric oxidation of fluorotelomer iodides is a potential source of perfluorocarboxylic acids.
Young
Cora J
CJ
Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario, Canada M5S 3H6.
Hurley
Michael D
MD
Wallington
Timothy J
TJ
Mabury
Scott A
SA
D000447:Aldehydes / Q000737:chemistry; D000465:Algorithms; D001272:Atmosphere / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry; D002713:Chlorine / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D006847:Hydrocarbons, Iodinated / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D015394:Molecular Structure; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D010782:Photolysis; D011789:Quantum Theory; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D000447:Aldehydes; D002264:Carboxylic Acids; D005466:Fluorocarbons; D006847:Hydrocarbons, Iodinated; D016877:Oxidants; D017665:Hydroxyl Radical; D002713:Chlorine