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Trifluoromethanol

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Trifluoromethanol
BERJAYA
Names
Preferred IUPAC name
Trifluoromethanol
Other names
Trifluoromethyl alcohol, perfluoromethanol
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/CHF3O/c2-1(3,4)5/h5H
    Key: WZCZNEGTXVXAAS-UHFFFAOYSA-N
  • C(O)(F)(F)F
Properties
CF3OH
Molar mass 86.013 g·mol−1
Appearance Colorless liquid
Density 1.5±0.1 g/cm3
Melting point −110.64 °C (−167.15 °F; 162.51 K)
Boiling point 22.4 °C (72.3 °F; 295.5 K) ±30.0°C
Hazards
Flash point 18.9 °C (66.0 °F; 292.0 K) ±15.6°
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Trifluoromethanol is a synthetic organic compound with the formula CF3OH.[1] It is also referred to as perfluoromethanol or trifluoromethyl alcohol. The compound is the simplest perfluoroalcohol.[2] The substance is a colorless gas, which is unstable at room temperature.

Synthesis

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Trifluoromethanol eliminates hydrogen fluoride in an endothermic reaction[3] and forms carbonyl fluoride.[4]

CF3OH ⇌ COF2 + HF

The equilibrium can be shifted toward trifluoromethanol at lower temperatures. If the synthesized trifluoromethanol is protonated by superacids, for example HSbF6 (fluoroantimonic acid), the equilibrium can be further shifted to the left towards the desired product. Other primary and secondary perfluoroalcohols exhibit similar instability.

At temperatures in the range of −120 °C, trifluoromethanol can be prepared by treating trifluoromethyl hypochlorite with hydrogen chloride:

CF3OCl + HCl → CF3OH + Cl2

In this reaction, the recombination of a partially positively charged chlorine atom (in trifluoromethyl hypochlorite) with a partially negatively charged chlorine atom (in hydrogen chloride) is used as elemental chlorine. The undesired products, by-products chlorine, hydrogen chloride, and chlorotrifluoromethane, 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. This fact can be explained by the absence of intramolecular H—F bonds, which are also not visible in the infrared gas phase spectrum.

Trifluoromethoxide

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Trifluoromethoxide (CF3O−) is the conjugate base of trifluoromethanol. Installing the trifluoromethoxy group, trifluoromethoxylation, is a well developed theme in agricultural and medicinal chemistry.[5]

Solutions or trifluoromethoxide can be prepared by treating carbonyl fluoride with sources of fluoride ion, e.g. NaF):

COF2 + F− → CF3O−

Some trifluoromethylethers can be cleaved to release trifluoromethoxide.[6]

CF3OAr + Nu → [Nu−Ar]+[CF3O]− (Nu = nucleophile, Ar = aryl group)

Trifluoromethyl benzoate is a related source of the trifluoromethoxide ion.[7]

In aqueous media, the CF3O− decomposes at room temperature.

Inorganic trifluoromethoxides MOCF3 vary in their stability, depending strongly on the countercation present. For example, Li, Na salts have not been isolated due to their instability toward decomposition to MF and COF2. On the other hand, the Cs salt is stable at room temperature and only decomposes slowly at 80 °C (<10% decomposition over 60 min), while the K and Rb salts are much more thermally labile.[8] In general, large cations stabilize the salt, with S(NMe2)3+ and NR4+ (R = alkyl) derivatives also demonstrating appreciable stability.[9][10] While AgOCF3 is poorly characterized and of low stability, the dimeric phosphine adduct [(tBu2PhP)Ag(μ-OCF3)]2 has been demonstrated to possess good thermal stability and ability to serve as a nucleophilic OCF3 source.[11]

Occurrence in upper layers of atmosphere

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Trifluoromethanol is generated in the stratosphere from CF3• radicals:[12]

CF3• + O2 + M → CF3O2• + M (M = third body)
CF3O2• + NO → CF3O• + NO2
CF3O2• + RH → CF3OH + R• (R = alkyl, hydroxyl)

While trifluoromethanol is unstable under normal conditions, in the atmosphere, its uncatalyzed decomposition is negligible due to the high activation energy of the gas-phase reaction (45–46 kcal·mol−1). Moreover, its photolytic lifetime is several million years at altitudes below 40 km.[13][14] Instead, its decomposition to carbonyl fluoride and hydrogen fluoride is believed to be catalyzed by species such as formic acid.[12]

See also

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References

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  1. ↑ Kloeter, Gerhard; Seppelt, Konrad (January 1979). "Trifluoromethanol (CF3OH) and trifluoromethylamine (CF3NH2)". J. Am. Chem. Soc. 101 (2): 347–349. Bibcode:1979JAChS.101..347K. doi:10.1021/ja00496a012.
  2. ↑ Seppelt, Konrad (May 1977). "Trifluoromethanol, CF3OH". Angewandte Chemie International Edition in English. 16 (5): 322–323. doi:10.1002/anie.197703221.
  3. ↑ Schneider, W. F. (April 11, 1996). "Energetics and Mechanism of Decomposition of CF3OH". J. Phys. Chem. 100 (15): 6097–6103. Bibcode:1996JPhCh.100.6097S. doi:10.1021/jp952703m.
  4. ↑ Seppelt, K. (1977). "Trifluormethanol, CF3OH. In: , ". Angew. Chem. (in German). 325 (89): 325. Bibcode:1977AngCh..89..325S. doi:10.1002/ange.19770890509.
  5. ↑ Leroux, Frédéric; Jeschke, Peter; Schlosser, Manfred (2005). "α-Fluorinated Ethers, Thioethers, and Amines: Anomerically Biased Species". Chemical Reviews. 105 (3): 827–856. doi:10.1021/cr040075b. PMID 15755078.
  6. ↑ Bonnefoy, Clémence; Gallego, Adrien; Delobel, Clément; Raynal, Betty; Decourt, Maxime; Chefdeville, Emmanuel; Hanquet, Gilles; Panossian, Armen; Leroux, Frédéric R.; Toulgoat, Fabien; Billard, Thierry (2024). "Unlocking the Power of Acyl Fluorides: A Comprehensive Guide to Synthesis and Properties". European Journal of Organic Chemistry. 27 (18) e202400142. doi:10.1002/ejoc.202400142.
  7. ↑ Zhou, Min; Ni, Chuanfa; Zeng, Yuwen; Hu, Jinbo (2018). "Trifluoromethyl Benzoate: A Versatile Trifluoromethoxylation Reagent". Journal of the American Chemical Society. 140 (22): 6801–6805. Bibcode:2018JAChS.140.6801Z. doi:10.1021/jacs.8b04000. PMID 29787259.
  8. ↑ "FULLY FLUORINATED ALKOXIDES: PART I. TRIFLUOROMETHOXIDES OF ALKALI METALS". cdnsciencepub.com. doi:10.1139/v65-251. Retrieved 2026-05-01.
  9. ↑ Farnham, W. B.; Smart, B. E.; Middleton, W. J.; Calabrese, J. C.; Dixon, D. A. (1985). "Crystal and molecular structure of tris(dimethylamino)sulfonium trifluoromethoxide. Evidence for negative fluorine hyperconjugation". Journal of the American Chemical Society. 107 (15): 4565–4567. doi:10.1021/ja00301a043. ISSN 0002-7863.
  10. ↑ Newton, Josiah J.; Jelier, Benson J.; Meanwell, Michael; Martin, Rainer E.; Britton, Robert; Friesen, Chadron M. (2020-03-06). "Quaternary Ammonium Trifluoromethoxide Salts as Stable Sources of Nucleophilic OCF 3". Organic Letters. 22 (5): 1785–1790. doi:10.1021/acs.orglett.0c00099. ISSN 1523-7060.
  11. ↑ Chen, Daoqian; Luo, Yongrui; Lu, Long; Shen, Qilong (2024-12-23). "[( t Bu 2 PhP)Ag(μ-OCF 3 )] 2 : A Thermally Stable, Light-Insensitive Nucleophilic Reagent for Trifluoromethoxylation". Organometallics. 43 (24): 3132–3136. doi:10.1021/acs.organomet.4c00073. ISSN 0276-7333.
  12. 1 2 Parandaman, Arathala; Perez, Josue E.; Sinha, Amitabha (13 December 2018). "Atmospheric Decomposition of Trifluoromethanol Catalyzed by Formic Acid". The Journal of Physical Chemistry A. 122 (49): 9553–9562. doi:10.1021/acs.jpca.8b09316.
  13. ↑ Schneider, W. F. (January 1995). "Atmospheric Chemistry of CF3OH: Is Photolysis Important?". Environmental Science & Technology. 29 (1): 247–250. Bibcode:1995EnST...29..247S. doi:10.1021/es00001a031. PMID 22200226.
  14. ↑ Wellington, T. J.; Schneider, W. F. (1994). "The Stratospheric Fate of CF3OH. In: Environmental Science & Technology 28/1994, S.". Environ. Sci. Technol. 28 (6): 1198–1200. doi:10.1021/es00055a036. PMID 22176252.
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