### Global Warming Potential

3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6-dodecafluoro-2-tri fluoromethyl-hexane

(HFE-7500) (CAS Number: 297730-93-9)

Summary:

This document describes analysis conducted by 3M to determine a Global Warming Potential (GWP) for HFE-7500. The format of this report is c onsistent with submittals to EPA for the use of Provisional GWPs. The Mandatory Reporting R ule requires facilities to monitor and report CO 2 -equivalent F-GHG process vent emissions, if those emissions exceed a threshold of 10,000 metric tons CO 2 -equivalent per year. [1] Estimated CO 2 -equivalent emissions are obtained by multiplying the F-GHG mass emissions by the Global Warming Potential (GWP) for the individual fluorinated gases that comprise the flow. EPA has provided a table of 100- year time horizon GWP values for about 70 individua l F-GHG, and specifies that these values are to be used for the purpose of computing CO 2 -equivalent emissions. [2] Default GWPs can be used for any fluorinated-GHG not listed in Table A-1. The regulation allows a facility to request a lower provisional GWP when cl ear scientific evidence exists to support
such a lower value.

Table A–1 does not list a GWP for 3-ethoxy-1,1,1,2, 3,4,4,5,5,6,6,6-dodecafluoro-2- trifluoromethyl-hexane (HFE-7500). As described in greater detail in a subsequent se ction, the atmospheric lifetime of 3-ethoxy-1,1,1,2,3,4,4, 5,5,6,6,6-dodecafluoro-2-trifluoromethylhexane has been determined to be 2.2 years based up on laboratory measurements; the radiative forcing of 3-ethoxy-1,1,1,2,3,4,4,5,5,6,6 ,6-dodecafluoro-2-trifluoromethyl-hexane has been measured using a quantitative infrared spe ctrum and the GWP of 3-ethoxy1,1,1,2,3,4,4,5,5,6,6,6-dodecafluoro-2-trifluoromet hyl-hexane has been calculated as 100
relative to CO 2 with a 100-year integration time horizon.

Evidence Supporting Estimated GWP:

F-GHG Identity: 3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6-do decafluoro-2-trifluoromethyl-hexane (HFE-7500)

Chemical Formula: CF 3 CF 2 CF 2 CF(OC 2 H 5 )CF(CF3) 2

CAS Number: 297730-93-9

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

Data and analysis: Goto et al. have measured kinetic rate constants for the vapor phase reaction of 3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6-dodeca fluoro-2-trifluoromethyl-hexane with OH using a relative rate technique, resulting in an at mospheric lifetime calculated at 2.2 years [3].

Goto et al . measured quantitative infrared spectra for 3-etho xy-1,1,1,2,3,4,4,5,5,6,6,6- dodecafluoro-2-trifluoromethyl-hexane. An FTIR spec trum for this compound is provided in Figure 1. The instantaneous forcing was calculated using the approximation method developed by Pinnock et al. [4] as 0.37 Wm -2 ppbv -1 . This calculation assumes that there is a constant concentration profile of the compound at a ll altitudes. To correct for this, the value was multiplied by a scaling factor as suggested by Sihra et al. [5] to account for the uneven vertical distribution of this compound in the atmos phere, resulting in a final radiative forcing
value of 0.30 Wm -2 ppbv -1

.Using these data in the equation referenced by the IPCC [6] to determine the GWP of a given

substance, a GWP of 100 relative to CO 2 with a 100-year integration time horizon was
established.

1. "Mandatory Reporting of Greenhouse Gases: Additiona l Sources of Fluorinated GHGs;
Final Rule" , Federal Register 75:230 (December 1, 2010) p.7477 4.

2. "Table A-1 to Subpart A of Part 98—Global Warming P otentials" : Table A-1 in 40 CFR part 98, subpart A.

3. Goto, M., Inque, Y., Kawasaski, M., Guschin, A.G ., Molina, L.T., Molina, M.J., Wallington, T.J., and Hurley, M.D., Environ. Sci. Technol., 36 , 2395-2402, 2002



### .

4. Pinnock, S., et al., Radiative forcing of climate by hydrochlorofluoroca rbons and hydrofluorocarbons. Journal of Geophysical Research, 1995. 100 (D11): p. 23227-23238.

5. Sihra, K., et al., Updated radiative forcing estimates of 65 halocarbo ns and nonmethane hydrocarbons , Journal of Geophysical Research, 2001. 106 (D17): p. 20493-20505.

6. IPCC, 2007: Climate Change 2007: Impacts, Adapta tion and Vulnerability. Contribution of Working Group II to the Fourth Assessment. Repor t of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Pal utikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge , UK, 976pp.

### Figure 1. FTIR Reference Spectrum of HFE-7500 0 .1 .2 .3 .4

4500 4000 3500 3000 2500 2000 1500 1000

Absorbance / Wavenumber (cm-1) Paged X-Zoom CURSOR

File # 3 : 58_HFE7500 3/6/2001 3:54 PM Res=None

HFE-7500, 58.45 ppm_m, 5.62 ppm, 24C, 10.4m, (10.0 ppm dilute withN2, Quant vs. 104_HFE7500), inst. O, blc.& H20 subtracted