Request to Use an Alternate GWP for 

Perfluoromethyl vinyl ether (CAS Number: 1187-93-5)

Summary:

EPA recently promulgated a mandatory reporting regulation for Fluorinated Greenhouse 

Gases (F-GHG). The regulation requires facilities to monitor and report CO2-equivalent 

F-GHG process vent emissions, if those emissions exceed a threshold of 10,000 metric 

tons CO2-equivalent per year. [1] Estimated CO2-equivalent emissions are obtained by 

multiplying the F-GHG mass emissions by the Global Warming Potential for the 

individual fluorinated gases that comprise the flow. EPA has provided a table of 100-

year time horizon GWP values for about 70 individual F-GHG, and specifies that these 

values are to be used for the purpose of computing CO2-equivalent emissions. [2] A 

default GWP value of 2,000 is to be used for any F-GHG not listed in Table A-1. The 

regulation allows a facility to request a lower provisional GWP when clear scientific 

evidence exists to support such a lower value.

Table A–1 does not list a GWP for perfluoromethyl vinyl ether. Perfluoromethyl vinyl 

ether is a short-lived fluorinated vinyl ether. The default GWP value of 2,000 is 

inappropriate for such gases and a substantial body of evidence in the peer-reviewed 

scientific literature has established that the GWPs of fluorinated vinyl ethers are modest. 

Kinetic rate constants for the atmospheric degradation of perfluoromethyl vinyl ether

have been measured in an environmental chamber; the atmospheric lifetime of 

perfluoromethyl vinyl ether has been estimated as 8 days; the infrared spectrum of 

perfluoromethyl vinyl ether has been accurately measured and the GWP of 

perfluoromethyl vinyl ether has been estimated as 2 relative to CO2 with a 100-year 

integration time horizon. DuPont is requesting a provisional GWP of 2 be assigned 

for perfluoromethyl vinyl ether.

Evidence Supporting Request:

F-GHG Identity: Perfluoromethyl vinyl ether

Chemical Formula: C3OF6

CAS Number: 1187-93-5

Estimated GWP: 2 relative to CO2 with a 100-year integration time horizon 

Data and analysis: Mashino et al. have measured kinetic rate constants for the vapor 

phase reaction of perfluoromethyl vinyl ether with OH. [3] OH radicals react with 

perfluoromethyl vinyl ether with a rate constant of (2.6 ± 0.3) × 10−12cm3 molecule−1s

−1

at 296 K in 700 Torr of air. The global and yearly averaged atmospheric lifetime of 

perfluoromethyl vinyl ether was estimated by scaling to the known lifetime of methyl 

chloroform. This approach gives an atmospheric lifetime of perfluoromethyl vinyl ether

with respect to reaction with OH of 0.023 years (8 days). Quantitative infrared crosssections of perfluoromethyl vinyl ether were obtained at 298 K in the region 500-4000 

cm-1

, and radiative forcing calculations were performed using the approximation method 
developed by Pinnock et al.. [4] The GWP of perfluoromethyl vinyl ether was estimated 

to be 4.57 × 10-4 relative to CFC-11 for a 100 year time horizon. The GWP of CFC-11 

relative to CO2 with a 100 year time horizon is 4,750. [5] Thus, the Mashino et al.

estimate of the GWP of perfluoromethyl vinyl ether relative to CO2 with a 100 year time 

horizon is 4.57 × 10-4 x 4,750 = 2. As a further check, we used the global and yearly 

averaged lifetime of 8 days measured by Mashino et al. and infrared cross-sections of 

perfluoromethyl vinyl ether obtained using ab initio quantum chemical methods 

recommended in the peer-reviewed scientific literature. [6-7] Radiative forcing 

calculations were again performed using the approximation method developed by 

Pinnock et al. [4] Using this approach, a GWP for perfluoromethyl vinyl ether of 3 

relative to CO2 with a 100-year integration time horizon was established. 

The methods used in determining this GWP value are essentially identical to those used 

for the values obtained for the gases listed in Table A-1: (1) the kinetic rate constants for 

reaction with critical atmospheric oxidants were measured and an atmospheric lifetime 

was determined; (2) the infrared absorption spectrum of the substance was measured; and 

(3) the atmospheric lifetime and infrared absorption spectrum were incorporated into a 

radiative transfer model to estimate the contribution of the substance to greenhouse 

forcing. 

Based on this publication in the peer-reviewed literature, DuPont requests that a 

provisional GWP of 2 be assigned for perfluoromethyl vinyl ether.

1. "Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated 

GHGs; Final Rule", Federal Register 75:230 (December 1, 2010) p.74774.

2. "Table A-1 to Subpart A of Part 98—Global Warming Potentials": Table A-1 in 

40 CFR part 98, subpart A.

3. Mashino, M., et al., Atmospheric Degradation of CF3OCFCF2: Kinetics and 

Mechanism of Its Reaction with OH Radicals and Cl Atoms. The Journal of 

Physical Chemistry A, 2000. 104(13): p. 2925-2930.

4. Pinnock, S., et al., Radiative forcing of climate by hydrochlorofluorocarbons and 

hydrofluorocarbons. Journal of Geophysical Research, 1995. 100(D11): p. 23227-

23238.

5. IPCC, Climate Change 2007: The Physical Science Basis. Contribution of 

Working Group I to the Fourth Assessment

Report of the Intergovernmental Panel on Climate Change. [Solomon, S., D. Qin, 

M. Manning, Z. Chen, M. Marquis, K.B. Averyt,

M. Tignor and H.L. Miller (eds.)]

2007, Cambridge, United Kingdom and New York, NY, USA: Cambridge 

University Press. 996 pp.

6. Blowers, P. and K. Hollingshead, Estimations of Global Warming Potentials from 

Computational Chemistry Calculations for CH2F2 and Other Fluorinated Methyl 

Species Verified by Comparison to Experiment. The Journal of Physical 

Chemistry A, 2009. 113(20): p. 5942-5950.
7. Halls, M.D. and H.B. Schlegel, Comparison of the performance of local, 

gradient-corrected, and hybrid density functional models in predicting infrared 

intensities. The Journal of Chemical Physics, 1998. 109(24): p. 10587-10593.