Atmospheric chemistry of perfluoroalkanesulfonamides:: Kinetic and product studies of the OH radical and Cl atom initiated oxidation of N-ethyl perfluorobutanesulfonamide
Atmospheric chemistry of perfluoroalkanesulfonamides:: Kinetic and product studies of the OH radical and Cl atom initiated oxidation of N-ethyl perfluorobutanesulfonamide
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DOI：
10.1021/es051362f
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发表时间：
2006-02-01
影响因子：
11.4
通讯作者：
Wallington, TJ
中科院分区：
文献类型：
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作者：
Martin, JW;Ellis, DA;Wallington, TJ
全氟辛烷磺酰胺[C8F17SO2N(R-1)(R-2)]存在于大气中，并可能通过大气传输和氧化，在偏远地区造成全氟羧酸盐(PFCA)和全氟辛烷磺酸盐(PFOS)污染。使用全氟丁烷磺酰类似物N-乙基全氟丁磺酰胺[NEtFBSA；C4F9SO2N(H)CH2CH3]进行了烟雾室内实验以评估这种可能性。用相对速率法测定了NEtFBSA与氯原子(296K)和OH自由基(301K)的反应速率常数分别为k(Cl)=(8.37+/-1.44)x10(-12)和k(OH)=(3.74+/-0.77)x10(-13)cm(-3)分子(-1)S(-1)，表明对流层中的反应将以OH反应为主。简单的模拟实验表明，与羟基的反应将主导全氟烷基磺酰胺从气相中的去除(湿沉积和干沉积将不是重要的)，并且NEtFBSA在气相中的大气寿命将为2050天，从而允许大量的远程大气传输。LC/MS/MS分析表明，氯原子引发氧化的主要产物是酮C4F9SO2(H)COCH3，醛1，C4F9SO2N(H)CH2CHO，经高分辨MS鉴定为C4F9SO2N(C2H5O)(-)，但其结构仍未确定。另一种反应产物是醛2，C4F9SO2(H)CHO，推测是醛1的二次氧化产物。在所有样品中都没有检测到超过空白水平的全氟丁烷磺酸盐，但在所有样品中都检测到了三种全氟烷基羧酸盐(C3F7CO2-，C2F5CO2-和CF3CO2-)。综上所述，结果表明，全氟辛烷磺酰胺可以作为包括全氟辛酸在内的全氟辛烷磺酸的大气来源。
Perfluorooctanesulfonamides [C8F17SO2N(R-1)(R-2)] are present in the atmosphere and may, via atmospheric transport and oxidation, contribute to perfluorocarboxylates (PFCA) and perfluorooctanesulfonate (PFOS) pollution in remote locations. Smog chamber experiments with the perfluorobutanesulfonyl analogue N-ethyl perfluoro-butanesulfonamide [NEtFBSA; C4F9SO2N(H)CH2CH3] were performed to assess this possibility. By use of relative rate methods, rate constants for reactions of NEtFBSA with chlorine atoms (296 K) and OH radicals (301 K) were determined to be k(Cl) = (8.37 +/- 1.44) x 10(-12) and k(OH) = (3.74 +/- 0.77) x 10(-13) cm(3) molecule(-1) s(-1), indicating OH reactions will be dominant in the troposphere. Simple modeling exercises suggest that reaction with OH radicals will dominate removal of perfluoroalkanesulfonamides from the gas phase (wet and dry deposition will not be important) and that the atmospheric lifetime of NEtFBSA in the gas phase will be 2050 days, thus allowing substantial long-range atmospheric transport. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis showed that the primary products of chlorine atom initiated oxidation were the ketone C4F9SO2(H)COCH3; aldehyde 1, C4F9SO2N(H)CH2CHO; and a product identified as C4F9SO2N(C2H5O)(-) by high-resolution MS but whose structure remains tentative. Another reaction product, aldehyde 2, C4F9SO2(H)CHO, was also observed and was presumed to be a secondary oxidation product of aldehyde 1. Perfluorobutanesulfonate was not detected above the level of the blank in any sample; however, three perfluoroalkanecarboxylates (C3F7CO2-, C2F5CO2-, and CF3CO2-) were detected in all samples. Taken together, results suggest a plausible route by which perfluorooctanesulfonamides may serve as atmospheric sources of PFCAs, including perfluorooctanoic acid.