Carbonyl fluoride

Structural formula
General
Surname	Carbonyl fluoride
other names	Fluorophosgene Carbonic acid difluoride Carbon oxide fluoride
Molecular formula	CF 2 O
Brief description	colorless, hygroscopic gas with a pungent odor
External identifiers / databases
CAS number 353-50-4 EC number 206-534-2 ECHA InfoCard 100.005.941 PubChem 9623 ChemSpider 9246 Wikidata Q251793
properties
Molar mass	66.01 g · mol -1
Physical state	gaseous
density	1.39 g cm −3 (solid, −190 ° C) 1.81 g cm −3 (liquid at boiling point) 2.97 g l −1 (gaseous, 0 ° C)
Melting point	−114.0 ° C
boiling point	−84.6 ° C
solubility	Hydrolysis in water
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 280-330-314 EUH: 071 P: 260-264-271-280-284-304 + 340
MAK	Switzerland: 2 ml m −3 or 5 mg m −3
Thermodynamic properties
ΔH f 0	−639.8 kJ / mol
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Carbonyl fluoride is the most common name for carbon oxide difluoride, CF ₂ O, the difluoride of carbonic acid . It is the fluorine - analogue of phosgene .

properties

Carbonyl fluoride is a poisonous, pungent smelling gas that smokes in the air due to its hygroscopicity . It is readily soluble in organic solvents (e.g. benzene , toluene , chlorobenzenes and others), it dissolves in water with rapid decomposition to carbon dioxide and hydrofluoric acid , which is why the organic solvents must be made anhydrous if they are to be used for synthesis or for working with carbonyl fluoride become:

${\displaystyle \mathrm {COF_{2}+H_{2}O\longrightarrow CO_{2}+2\ HF} }$

presentation

Carbonyl fluoride is usually formed as a decomposition product of fluorinated hydrocarbons when they are thermally decomposed, for example from trifluoromethanol or tetrafluoromethane in the presence of water:

${\displaystyle \mathrm {CF_{4}+H_{2}O\longrightarrow COF_{2}+2\ HF} }$

It can also be synthesized from carbon monoxide and fluorine:

${\displaystyle \mathrm {CO+F_{2}\longrightarrow COF_{2}} }$

In the laboratory, pure carbonyl fluoride is produced by converting carbon monoxide with silver (II) fluoride in a copper tube:

${\displaystyle {\ce {CO + 2 AgF2 -> COF2 + 2 AgF}}}$

use

On a laboratory scale, carbonyl fluoride can be used for fluorine syntheses, as it very easily absorbs oxygen by releasing the fluorine atoms and reacts further to form carbon dioxide .

Toxic effect

Inhaled carbonyl fluoride irritates skin, eyes and respiratory tract. In the eyes and skin, pain , redness , severe burns and visual impairment occur due to the withdrawal of water from the tissue and also due to the resulting hydrogen fluoride . Carbonyl fluoride forms hydrofluoric acid with body fluids, which explains the corrosive and toxic effects. If it comes into contact with liquid carbonyl fluoride, frostbite occurs . After prolonged absorption through the respiratory tract, the patient exhibits a sore throat , cough and dyspnoea . Symptoms can be delayed. The worst inhalation consequence can be toxic pulmonary edema . This is to be treated with cortisone , in any case also preclinically.

The toxicity of carbonyl fluoride is mainly explained by hydrolysis with subsequent hydrofluoric acid poisoning, but animal experiments indicate a higher toxicity compared to gaseous hydrogen fluoride. This could be due to a greater depth of penetration into the airways. Direct reactions with biomolecules, which are decisive for phosgene toxicity, seem to play a subordinate role with COF ₂ , since it decomposes much more quickly on contact with moisture. This fact and the associated stronger irritant effect (warning) could explain the lower toxicity of carbonyl fluoride compared to phosgene. Overall, there is far less toxicological data on carbonyl fluoride than on phosgene, and the lethal doses differ considerably in some studies.

Individual evidence

1. ↑ ^{a b c d e f g h} Entry on carbonyl fluoride in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
2. ^ VO Ruff and G. Miltschitzky: Z. anorg. u. general Chem., 221 , 154 (1934).
3. ↑ Swiss Accident Insurance Fund (Suva): Limits - Current MAK and BAT values (search for 353-50-4 or carbonyl fluoride ), accessed on November 2, 2015.
4. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-19.
5. ↑ G. Brauer (Ed.), Handbook of Preparative Inorganic Chemistry 2nd ed., Vol. 1, Academic Press 1963, pp. 206-208.
6. ^ MW Farlow et al .: Carbonyl fluoride . In: Eugene G. Rochow (Ed.): Inorganic Syntheses . tape 6 . McGraw-Hill Book Company, Inc., 1960, pp. 155-158 (English).
7. ↑ Adolph J. Januszkiewicz, Matthew A. Bazar, Lee CB Crouse, Michael A. Chapman, Steven E. Hodges, Steven J. McCormick, Arthur J. O'Neill: Morbidity and mortality resulting from acute inhalation exposures to hydrogen fluoride and carbonyl fluoride in council . In: Inhalation Toxicology . tape 30 , no. 3 , 2018, p. 114–123 , doi : 10.1080 / 08958378.2018.1465494 .
8. ↑ Acute Exposure Guideline Levels for Selected Airborne Chemicals: Volume 18 - Chapter: 2 Carbonyl Fluoride , 2014.