Trifluoroiodomethane Explained

Trifluoroiodomethane, also referred to as trifluoromethyl iodide is a halomethane with the formula CF₃I. It is an experimental alternative to Halon 1301 (CBrF₃) in unoccupied areas.^[1] It would be used as a gaseous fire suppression flooding agent for in-flight aircraft and electronic equipment fires.

Chemistry

It is used in the rhodium-catalyzed α-trifluoromethylation of α,β-unsaturated ketones.^[2]

It can be used as a new generation fire extinguishing agent to replace Halon in fire protection systems.^[3] The mechanism of extinguishing fires for CF₃I is active and primarily based on interruption of the chain reaction in the combustion area of the flame by so-called "negative" catalytic action.^[4] It is also used as an eco-friendly insulation gas to replace SF₆ in electrical power industry.^[5]

In the presence of sunlight or at temperatures above 100 °C it can react with water, forming hazardous by-products such as hydrogen fluoride (HF), hydrogen iodide (HI) and carbonyl fluoride (COF₂).

Environmental effects

Trifluoroiodomethane contains carbon, fluorine, and iodine atoms. Although iodine is several hundred times more efficient at destroying stratospheric ozone than chlorine, experiments have shown that because the weak C-I bond breaks easily under the influence of water (owing to the electron-attracting fluorine atoms), trifluoroiodomethane has an ozone depleting potential less than one-thousandth that of Halon 1301 (0.008-0.01). Its atmospheric lifetime, at less than 1 month, is less than 1 percent that of Halon 1301, and less even than hydrogen chloride formed from volcanoes.

There is, however, still the problem of the C-F bonds absorbing in the atmospheric window.^[6] However, the IPCC has calculated the 100-year global warming potential of trifluoroiodomethane to be 0.4 (i.e., 40% of that of CO₂).^[7]

Further reading

• Book: 10.17226/11090 . Iodotrifluoromethane . 2004 . 25032315 . 978-0-309-09307-1 . National Research Council (US) Subcommittee on Iodotrifluoromethane .
• Solomon . Susan . Burkholder . James B. . Ravishankara . A. R. . Garcia . Rolando R. . Ozone depletion and global warming potentials of CF₃I . Journal of Geophysical Research . 1994 . 99 . D10 . 20929 . 10.1029/94JD01833 . 1994JGR....9920929S .
• Duan . Y. Y. . Shi . L. . Sun . L. Q. . Zhu . M. S. . Han . L. Z. . Thermodynamic Properties of Trifluoroiodomethane (CF₃I) . International Journal of Thermophysics . 1 March 2000 . 21 . 2 . 393–404 . 10.1023/A:1006683529436 . 118125837 .
• Duan . Yuan-Yuan . Shi . Lin . Zhu . Ming-Shan . Han . Li-Zhong . Surface tension of trifluoroiodomethane (CF₃I) . Fluid Phase Equilibria . January 1999 . 154 . 1 . 71–77 . 10.1016/S0378-3812(98)00439-7 .
• Duan . Y. Y. . Sun . L. Q. . Shi . L. . Zhu . M. S. . Han . L. Z. . Thermal Conductivity of Gaseous Trifluoroiodomethane (CF₃I) . Journal of Chemical & Engineering Data . 1 September 1997 . 42 . 5 . 890–893 . 10.1021/je9700378 .
• Duan . Yuan-Yuan . Shi . Lin . Zhu . Ming-Shan . Han . Li-Zhong . Critical Parameters and Saturated Density of Trifluoroiodomethane (CF₃I) . Journal of Chemical & Engineering Data . 1 May 1999 . 44 . 3 . 501–504 . 10.1021/je980251b .
• Book: Markgraf . Stewart J. . Wells . J. R. . Wiseman . Floyd L. . Chamber Studies of Photolysis and Hydroxyl Radical Reactions of Trifluoroiodomethane . 30 April 1996 . .

External links

• Book: 10.17226/11090 . Iodotrifluoromethane . 2004 . 25032315 . 978-0-309-09307-1 . National Research Council (US) Subcommittee on Iodotrifluoromethane . Physical and Chemical Properties And Efficacy . 15–17 . https://www.ncbi.nlm.nih.gov/books/NBK207826/ .
• Data sheet (in Japanese)
• Material Safety Data Sheet CF₃I (in English)
• CF₃I can be used as fire extinguishing agent

Notes and References

1. Web site: Halon Substitute Protects Aircrews and the Ozone Layer. Vitali. Juan. www.afrlhorizons.com. en-US. https://web.archive.org/web/20070711055402/http://www.afrlhorizons.com/Briefs/0012/ML0008.html. 11 July 2007. dead. 2017-09-06.
2. Web site: Trifluoroiodomethane 171441. Sigma-Aldrich. 2017-09-06.
3. Web site: Fire extinguishing agents trifluoroiodomethane/CF₃I. beijingyuji. 2018-09-20.
4. Web site: CFI rim seal fire protection for floating roof tanks. 2018-09-20.
5. Katagiri . H. . Kasuya . H. . Mizoguchi . H. . Yanabu . S. . Investigation of the Performance of CF₃I Gas as a Possible Substitute for SF₆ . . October 2008 . 15 . 5 . 1424–1429 . 10.1109/TDEI.2008.4656252 . 21905295 .
6. Shimanouchi . T. . Tables of molecular vibrational frequencies. Consolidated volume II . Journal of Physical and Chemical Reference Data . July 1977 . 6 . 3 . 993–1102 . 10.1063/1.555560 . 1977JPCRD...6..993S .
7. Web site: Listing of GWP Values as per Report IPCC WG1 AR4. Ramfjord. Birgit. 2012-03-05. Swedish Defence Materiel Administration. https://web.archive.org/web/20160313122319/http://www.fmv.se/Global/Dokument/Engelska%20webben/Our%20activities/Enviromental%20work/Environmental%20criteria%20documents/121023/12FMV1533%202%201%20GWP%20eng.pdf. 13 March 2016. 7 September 2017.