Atmospheric Chemistry of 1H‑Heptafluorocyclopentene
(cyc-CF2CF2CF2CFCH−):
Rate Constant, Products, and Mechanism of Gas-Phase Reactions with
OH Radicals, IR Absorption Spectrum, Photochemical Ozone Creation
Potential, and Global Warming Potential
posted on 2016-11-17, 00:00authored byDongpeng Liu, Sheng Qin, Wei Li, Di Zhang, Zhikai Guo
The
rate constant for gas-phase reactions of OH radicals with 1H-heptafluorocyclopentene (cyc-CF2CF2CF2CFCH−) was measured using a relative
rate method at 298 K: (5.20 ± 0.09) × 10–14 cm3 molecule–1 s–1. The quoted uncertainty includes two standard deviations from the
least-squares regression, the systematic error from the GC analysis,
and the uncertainties of the rate constants of the reference compounds.
The OH-radical-initiated oxidation of cyc-CF2CF2CF2CFCH– gives the main products COF2, CO, and CO2, leading to negligible environmental
impact. For consumptions of cyc-CF2CF2CF2CFCH– of less than 54%, the yield of the formation
of ([COF2] + [CO] + [CO2])/5 (based on the conservation
of carbon) was 0.99 ± 0.02, which is very close to 100%. A possible
degradation mechanism was proposed. The radiative efficiency (RE)
of cyc-CF2CF2CF2CFCH–
measured at room temperature was 0.215 W m–2 ppb–1. The atmospheric lifetime of cyc-CF2CF2CF2CFCH– was calculated as 0.61
year, and the photochemical ozone creation potential (POCP) was negligible.
The 20-, 100-, and 500-year time horizon global warming potentials
(GWPs) were estimated as 153, 42, and 12, respectively.