Trifluoromethanol is the organic compound with the formula . It is also referred to as perfluoromethanol or trifluoromethyl alcohol. The compound is the simplest

perfluoroalcohol Fluoroalcohols are organofluorine compounds consisting of an alcohol functional group with at least one C-F bond. These compounds often have distinctive solvent properties. Perfluoroalcohols Most primary and secondary perfluoroalcohols are unstab ...

. The substance is a colorless gas, which is unstable at room temperature.

Synthesis

Like all primary and secondary perfluoroalcohols, trifluoromethanol eliminates

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 ...

in an endothermic reaction and forms

carbonyl fluoride Carbonyl fluoride is a chemical compound with the formula COF2. It is a carbon oxohalide. This gas, like its analog phosgene, is colourless and highly toxic. The molecule is planar with ''C''2v symmetry, bond lengths of 1.174 Å (C=O) and 1.312 Å ...

. : ⇌ + (I) At temperatures in the range of -120 °C, trifluoromethanol can be prepared from trifluoromethoxy chloride and

hydrogen chloride The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride ga ...

: : + → + (II) In this reaction, the recombination of a partially positively charged chlorine atom (in trifluoromethoxy chloride) with a partially negatively charged chlorine atom (in hydrogen chloride) is used as elemental chlorine. The undesired products, by-products chlorine,

, and

chlorotrifluoromethane Chlorotrifluoromethane, R-13, CFC-13, or Freon 13, is a non-flammable, non-corrosive chlorofluorocarbon (CFC) and also a mixed halomethane. It is a man-made substance used primarily as a refrigerant. When released into the environment, CFC-13 ha ...

, can be removed by evaporation at -110 °C. Trifluoromethanol has a melting point of -82 °C and a calculated boiling point of about -20 °C. The boiling point is thus about 85 K lower than that of

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...

. This fact can be explained by the absence of intramolecular H—F bonds, which are also not visible in the infrared gas phase spectrum. A simpler synthesis uses the reaction (I); an equilibrium can be shifted to the thermodynamically preferred trifluoromethanol at lower temperatures. If the synthesized trifluoromethanol is protonated by superacids, for example (

fluoroantimonic acid Fluoroantimonic acid is a mixture of hydrogen fluoride and antimony pentafluoride, containing various cations and anions (the simplest being and ). This substance is a superacid that can be over a billion times stronger than 100% pure sulfuri ...

), the equilibrium can be further shifted to the left towards the desired product. Similar to reaction (I), trifluoromethoxides () can be prepared from saline-type fluorides (e.g., ) and

. However, if the ion is, for example, in an aqueous solution displaced by an acid, trifluoromethanol decomposes at the room temperature.

Occurrence in upper layers of atmosphere

While trifluoromethanol is unstable under normal conditions, it is generated in the stratosphere from and radicals by reaction with and radicals. In this case, decomposition of trifluoromethanol is negligible under the conditions prevailing in the atmosphere due to the high activation energy of the reaction. The expected lifetime of trifluoromethanol is several million years at altitudes below 40 km.

References

{{Alcohols Trifluoromethyl compounds Primary alcohols Trifluoromethoxy compounds Organic compounds with 1 carbon atom Substances discovered in the 1970s

Synthesis

Occurrence in upper layers of atmosphere

See also

References