Request to Use an Alternate GWP for

Perfluoroethyl vinyl ether (CAS Number: 10493-43-3)

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 perfluoroethyl vinyl ether. Perfluoroethyl

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. 

The atmospheric lifetime of perfluoroethyl vinyl ether has been estimated as 8.077 days

using the AOPWIN module of EPA’s EPI SuiteTM v4.10 exposure assessment modeling 

tool; the infrared spectrum of perfluoroethyl vinyl ether has been accurately estimated 

using ab initio quantum chemical methods recommended in the peer-reviewed scientific 

literature and the GWP of perfluoroethyl vinyl ether has been estimated as 3 relative to 

CO2 with a 100-year integration time horizon. DuPont is requesting a provisional 

GWP of 3 be assigned for perfluoroethyl vinyl ether.

Evidence Supporting Request:

F-GHG Identity: Perfluoroethyl vinyl ether

Chemical Formula: C4OF8

CAS Number: 10493-43-3

Estimated GWP: 3 relative to CO2 with a 100-year integration time horizon 

Data and analysis: A global and yearly averaged atmospheric lifetime for 

perfluoroethyl vinyl ether of 8.077 days was estimated using the AOPWIN module of 

EPA’s EPI SuiteTM v4.10 exposure assessment modeling tool. [3] 

For comparison, Mashino et al. have measured kinetic rate constants for the vapor 

phase reaction of the chemically very similar perfluoromethyl vinyl ether with OH. [4] 

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). 

Thus the lifetime 8.077 days obtained for perfluoroethyl vinyl ether is reasonable. 

Infrared cross-sections of perfluoroethyl vinyl ether were obtained using ab initio

quantum chemical methods recommended in the peer-reviewed scientific literature. [5-6] 

Radiative forcing calculations were performed using the approximation method 

developed by Pinnock et al. [7] Using this approach, a GWP for perfluoroethyl 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 3 be assigned for perfluoroethyl 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. EPI SuiteTM v4.10, EPA Office of Pollution Prevention & Toxics and Syracuse 

Research Corporation (2000-2008).

4. 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.

5. 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.

6. 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.

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

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

23238.