4:2氟调聚物碘化物（n-C4F9CH2CH2I）的大气化学：光解动力学及产物、与OH自由基和Cl原子的反应
Atmospheric chemistry of 4:2 fluorotelomer iodide (n-C4F9CH2CH2I): kinetics and products of photolysis and reaction with OH radicals and Cl atoms.
作者信息
Young Cora J, Hurley Michael D, Wallington Timothy J, Mabury Scott A
机构信息
Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario, Canada M5S 3H6.
出版信息
J Phys Chem A. 2008 Dec 25;112(51):13542-8. doi: 10.1021/jp807322x.
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.
采用相对速率技术研究了上述反应，并测定了在295K、总压700托条件下k(Cl + C₄F₉CH₂CH₂I) = (1.25 ± 0.15) × 10⁻¹²和k(OH + C₄F₉CH₂CH₂I) = (1.2 ± 0.6) × 10⁻¹² cm³·分子⁻¹·s⁻¹的速率常数。通过原位傅里叶变换红外光谱和离线分析检测到氟代调聚醛(C₄F₉CH₂CHO)、全氟醛(C₄F₉CHO)、氟代调聚酸(C₄F₉CH₂C(O)OH)、氟代调聚过氧酸(C₄F₉CH₂C(O)OOH)以及几种全氟羧酸，它们是氯原子引发的C₄F₉CH₂CH₂I在空气中氧化的产物。记录了C₄F₉CH₂CH₂I和C₂H₅Cl在200 - 400nm范围内的紫外可见光谱。C₄F₉CH₂CH₂I的光解产生C₄F₉CH₂CHO作为主要观测产物。假设光解量子产率为1，计算得出C₄F₉CH₂CH₂I的大气寿命由光解决定，约为几天。提出了氟代调聚碘化物(CₓF₂ₓ₊₁CH₂CH₂I，其中x = 2、4、6……)的大气氧化机制。氟代调聚碘化物的大气氧化是全氟羧酸的一个潜在来源。
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