Ballesteros Bernabé, Jiménez Elena, Moreno Alberto, Soto Amparo, Antiñolo María, Albaladejo José
Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avenida Camilo José Cela 1B, 13071 Ciudad Real, Spain; Instituto de Investigación en Combustión y Contaminación Atmosférica, Universidad de Castilla-La Mancha, Camino de Moledores s/n, 13071 Ciudad Real, Spain.
Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avenida Camilo José Cela 1B, 13071 Ciudad Real, Spain; Instituto de Investigación en Combustión y Contaminación Atmosférica, Universidad de Castilla-La Mancha, Camino de Moledores s/n, 13071 Ciudad Real, Spain.
Chemosphere. 2017 Jan;167:330-343. doi: 10.1016/j.chemosphere.2016.09.156. Epub 2016 Oct 11.
Rate coefficients for the gas-phase reactions of CFCHCH (x = 1, 2, 3, 4 and 6) with Cl atoms were determined at (298 ± 2) K and (710 ± 5) Torr of air using a relative rate technique. Two experimental setups with simulation chambers were employed with Fourier Transform Infrared (FTIR) spectroscopy and Gas Chromatography coupled to Mass Spectrometry (GC-MS) as detection techniques. The Cl-rate coefficients obtained were (in 10 cm molecule s): (0.85 ± 0.11) for CFCHCH, (1.11 ± 0.08) for CFCHCH, (1.12 ± 0.18) for CFCHCH, (0.97 ± 0.09) for CFCHCH, and (0.99 ± 0.08) for CFCHCH. Additionally, the gas-phase products were identified and quantified, when possible, by FTIR spectroscopy or GC-MS. The main reaction product was reported to be CFC(O)CHCl. The fluorinated species, CFCHO and CFC(O)CHCl, were identified. CFC(O)CHCl and CFCHO were found to be formed with molar yield of (69 ± 5)% and (9 ± 1)%, respectively. The global lifetime of the investigated CFCHCH due to their Cl-reaction is more than 100 days so this route does not compete with the removal by OH radicals. This lifetime is long enough for CFCHCH to be transported to remote areas where they can be degraded. However, at a local scale, in marine regions at dawn the removal of CFCHCH is expected to occur in ca. 1 day. The atmospheric degradation of these hydrofluoroolefins by Cl atoms is not expected to be a source of bioaccumulative perfluorinated carboxylic acids, CFC(O)OH. Additionally, the UV absorption cross sections of CFC(O)CHCl were determined together with the rate coefficient of the OH reaction by an absolute kinetic method at room temperature.
采用相对速率技术，在（298±2）K和（710±5）托的空气条件下，测定了CFCHCH（x = 1、2、3、4和6）与氯原子气相反应的速率系数。使用了两个带有模拟腔的实验装置，采用傅里叶变换红外光谱（FTIR）和气相色谱-质谱联用（GC-MS）作为检测技术。得到的与氯反应的速率系数（单位为10⁻¹⁵ cm³ 分子⁻¹ s⁻¹）如下：CFCHCH为（0.85±0.11），CFCHCH为（1.11±0.08），CFCHCH为（1.12±0.18），CFCHCH为（0.97±0.09），CFCHCH为（0.99±0.08）。此外，尽可能通过FTIR光谱或GC-MS对气相产物进行了鉴定和定量。据报道，主要反应产物为CFC(O)CHCl。鉴定出了含氟物种CFCHO和CFC(O)CHCl。发现CFC(O)CHCl和CFCHO的摩尔产率分别为（69±5）%和（9±1）%。所研究的CFCHCH因与氯反应的全球寿命超过了100天，所以这条途径与羟基自由基的去除过程不构成竞争。这个寿命足够长，使得CFCHCH能够传输到偏远地区并在那里降解。然而，在局部尺度上，在黎明时分的海洋区域，CFCHCH预计大约在1天内被去除。预计氯原子对这些氢氟烯烃的大气降解不会成为生物累积性全氟羧酸CFC(O)OH的来源。此外，通过绝对动力学方法在室温下测定了CFC(O)CHCl的紫外吸收截面以及与羟基反应的速率系数。
