1. Industrial Search for Greenhouse Gas Replacements Zhuangjie Li Department of Chemistry and Biochemistry California State University Fullerton Fullerton, CA 92834

2. Outline Introduction Global Warming Potentials (GWPs) GHG alternatives search strategy Potential GHG replacement compounds Conclusion

3. Global warming (GW) - threats to our welfare - draughts and floods, decrease food production - draughts and floods, decrease food production - Sea level rise, high tides, hurricanes, beach erosion - Sea level rise, high tides, hurricanes, beach erosion Anthropogenic GW contributor – Greenhouse gases (GHG) - CO 2 – from fossil fuel usage - non-CO 2 trace gases – industrial and consumer usage Industrial – Solvents, cleaning, etching agents etc. Consumer – Refrigerators, air conditioners, spray products etc. Ex. CFCl 3, CF 2 Cl 2, SF 6, C 2 F 6, NF 3 etc.

4. To mitigate Global warming - Reduce CO 2 loading in the atmosphere - improve fuel efficiency; develop wind, solar, renewable energy etc. For non-CO 2 GHG – Develop new chemicals that are environmentally benign (Solvents, cleaning agents, foam blowing materials, refrigerants, etc.) Question: How do we know how much a newly developed chemical would contribute to GW?

5. Global Warming Potentials (GWPs) – A tool to quantitatively measure the contribution of a compound to global warming. Sources: Brakkee et al. Int J LCA 13 191 (2008)

6. Sources: NIST http://webbook.nist.gov/chemistry/form-ser.html

9. Summary of Atmospheric Lifetime and GWPs for HCFCs for 20, 100, and 500 Year Time Horizons _______________________________________________________________________________________ Global Warming Potentials GasAtmospheric_________ years___________ Lifetime, years20100500 ________________________________________________________________________________________ CFC- 12 100 7,900 8,500 4,200 HCFC-22 12 4,662 1,900 535 HCFC-123 1.4 303 120 28 HCFC- 124 6.2 1,823 620 176 HCFC-141b 9.1 1,701 700 177 H CFC- 142b 18 4,396 2,300 610 HCFC-225 ca 2.0 414 180 38 HCFC-225cb 6.31,597 620 154 ______________________________________________________________________________________ Sources: WMO and IPCC reports (1999-2007)

10. Summary of Atmospheric Lifetime and GWPs for HFCs for 20, 100, and 500 Year Time Horizons _______________________________________________________________________________________ Global Warming Potentials GasAtmospheric _________ years___________ Lifetime, years 20 100 500 ________________________________________________________________________________________ HFC-32 5.2 2,920 880 276 HFC- 125 29.4 5,738 3,800 1,083 HFC- 134 10.4 3,288 1,200 356 HFC- 134a 14 4,845 1,600 589 HFC-143 3.7 1,017 370 94 HFC- 143a 47 5,695 5,400 1,537 HFC-152a 1.5 499 190 46 HFC-161 0.322 10 2 HFC- 227ea 35.7 5,395 3,800 1,172 HFC-236fa 2226,125 9,400 5,930 HFC-245fa 7.673,094 995 309 HFC-365mfc 10.72,709 910 296 ______________________________________________________________________________________ Sources: WMO and IPCC reports (1999-2007)

11. Summary of Atmospheric Lifetime and GWPs for HFEs for 20, 100, and 500 Year Time Horizons _______________________________________________________________________________________ Global Warming Potentials GasAtmospheric _________ years___________ Lifetime, years 20 100 500 ________________________________________________________________________________________ HFE-2160.0100.014 0.0040.001 HFE-227 11.3 3,000 1,100 300 HFE-245fa 0.401,900 560 170 HFE-245fb0.3685025079 HFE- 134 0.439,400 4,300 1,300 HFE- 125 0.4212,100 14,400 9,400 HFE-1450.3253015049 HFE-2270.2837011035 HFE-236fa0.4441001500450 HFE-236fb0.341600460140 HFE-2630.2037113 HFE-245fc0.3091027085 HFE-3290.492800870270 HFE-3380.431800520160 HFE-3490.411200350110 __________________________________________________________________________________ Sources: WMO and IPCC reports (1999-2007); Li et al. JGR 2000, 2001

12. Additional requirements for a GHG replacement compound: -Proper physical properties -non-flammable -low toxicity -low cost All these requirements make the search for desirable GHG replacements challenging

13. Conclusions Key factors in searching GHG replacement: short atmospheric lifetime Three groups of compounds are current focus: HCFCs, HFCs, and HFEs. HCFCs, HFCs, and HFEs. Search for GHG replacements is on the way Challenge: Meeting all requirements: physical properties, safe to use, low cost, and benign to the environments.

14. Thank you