Atmospheric Degradation Initiated by OH Radicals of the Potential Foam Expansion Agent, CF3(CF2)2CH═CH2 (HFC-1447fz): Kinetics and Formation of Gaseous Products and Secondary Organic Aerosols

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• 作者：Elena Jiménez ; Sergio González ; Mathieu Cazaunau ; Hui Chen ; Bernabé Ballesteros ; Véronique Da?le ; José Albaladejo ; Abdelwahid Mellouki
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：February 2, 2016
• 年：2016
• 卷：50
• 期：3
• 页码：1234-1242
• 全文大小：440K
• ISSN：1520-5851

文摘

The assessment of the atmospheric impact of the potential foam expansion agent, CF₃(CF₂)₂CH═CH₂ (HFC-1447fz), requires the knowledge of its degradation routes, oxidation products, and radiative properties. In this paper, the gas-phase reactivity of HFC-1447fz with OH radicals is presented as a function of temperature, obtaining k_OH?(T = 263–358 K) = (7.4 ± 0.4) × 10^–13exp{(161 ± 16)/T} (cm³·molecule^–1·s^–1) (uncertainties: ±2σ). The formation of gaseous oxidation products and secondary organic aerosols (SOAs) from the OH + HFC-1447fz reaction was investigated in the presence of NO_x at 298 K. CF₃(CF₂)₂CHO was observed at low- and high-NO_x conditions. Evidence of SOA formation (ultrafine particles in the range 10–100 nm) is reported with yields ranging from 0.12 to 1.79%. In addition, the absolute UV (190–368 nm) and IR (500–4000 cm^–1) absorption cross-sections of HFC-1447fz were determined at room temperature. No appreciable absorption in the solar actinic region (λ > 290 nm) was observed, leaving the removal by OH radicals as the main atmospheric loss process for HFC-1447fz. The major contribution of the atmospheric loss of HFC-1447fz is due to OH reaction (84%), followed by ozone (10%) and chlorine atoms (6%). Correction of the instantaneous radiative efficiency (0.36 W m^–2·ppbv^–1) with the relatively short lifetime of HFC-1447fz (ca. 8 days) implies that its global warming potential at a time horizon of 100 year is negligible (0.19) compared to that of HCFC-141b (782) and to that of modern foam-expansion blowing agents (148, 882, and 804 for HFC-152a, HFC-245fa and HFC-365mfc, respectively).