Trifluoroiodomethane, also referred to as trifluoromethyl iodide is a
halomethane Halomethane compounds are derivatives of methane () with one or more of the hydrogen atoms replaced with halogen atoms ( F, Cl, Br, or I). Halomethanes are both naturally occurring, especially in marine environments, and human-made, most notably ...
with the formula CF
3I. It is an experimental alternative to
Halon 1301 (CBrF
3) in unoccupied areas. 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 Trifluoromethylation in organic chemistry describes any organic reaction that introduces a trifluoromethyl group in an organic compound. Trifluoromethylated compounds are of some importance in pharmaceutical industry and agrochemicals. Several notab ...
of α,β-unsaturated
ketones
In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bon ...
.
It can be used as a new generation fire extinguishing agent to replace Halon in fire protection systems. The mechanism of extinguishing fires for CF
3I is active and primarily based on interruption of the chain reaction in the combustion area of the flame by so-called "negative" catalytic action. It is also used as an eco-friendly insulation gas to replace
SF6 in electrical power industry.
In the presence of sunlight or at temperatures above 100 °C it can react with water, forming hazardous by-products such as
hydrogen fluoride
Hydrogen fluoride (fluorane) is an inorganic compound with the chemical formula . This colorless gas or liquid is the principal industrial source of fluorine, often as an aqueous solution called hydrofluoric acid. It is an important feedstock i ...
(HF),
hydrogen iodide
Hydrogen iodide () is a diatomic molecule and hydrogen halide. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a strong acid. Hydrogen iodide and hydroiodic acid are, however, different in that the former is a gas under sta ...
(HI) and
carbonyl fluoride (COF
2).
Environmental effects
Trifluoroiodomethane contains
carbon,
fluorine
Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...
, and
iodine
Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...
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
An atmospheric window is a range of wavelengths of the electromagnetic spectrum that can pass through the atmosphere of Earth. The optical, infrared and radio windows comprise the three main atmospheric windows. The windows provide direct channels ...
. However, the IPCC has calculated the 100-year
global warming potential of trifluoroiodomethane to be 0.4 (i.e., 40% of that of CO
2).
References
Further reading
*
*
*
*
*
*
*
External links
*
Data sheet (in Japanese)Material Safety Data Sheet CF3I (in English)
{{fluorine compounds
Halomethanes
Fire suppression agents
Trifluoromethyl compounds
Organoiodides