Hexafluoroacetone

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Hexafluoroacetone
Hexafluoropropanone skeletal structure
Hexafluoropropanone 3D structure
Names
IUPAC name
1,1,1,3,3,3-hexafluoro-2-propanone
Other names
perfluoroacetone
acetone hexafluoride
perfluoro-2-propanone
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.010.616
RTECS number UC2450000
Properties
C3F6O
Molar mass 166.02 g/mol
Appearance Colorless gas
Odor musty[1]
Density 1.32 g/ml, liquid
Melting point −129 °C (144 K)
Boiling point −28 °C (245 K)
Reacts with water
Vapor pressure 5.8 atm (20 °C)[1]
Hazards
Main hazards Toxic (T),
Corrosive (C)
R-phrases (outdated) R14, R23/24/25,
R34, R60, R63
S-phrases (outdated) S7/9, S26, S28,
S36, S45, S53
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorus Special hazard W: Reacts with water in an unusual or dangerous manner. E.g., cesium, sodiumNFPA 704 four-colored diamond
Flash point Nonflammable[1]
US health exposure limits (NIOSH):
PEL (Permissible)
none[1]
REL (Recommended)
TWA 0.1 ppm (0.7 mg/m3) [skin][1]
IDLH (Immediate danger)
N.D.[1]
Related compounds
Related ketones;
organofluorides
Acetone;
Hexafluoro-2-propanol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Hexafluoroacetone (HFA) is a chemical compound with the formula (CF3)2CO. It is structurally similar to acetone; however, its reactivity is markedly different. It a colourless, hygroscopic, nonflammable, highly reactive gas characterized by a musty odour,[2] the most common form of this substance is hexafluoroacetone sesquihydrate (1.5 H2O), which is a geminal diol.

Synthesis[edit]

The industrial route to HFA involves treatment of hexachloroacetone with HF:[3]

(CCl3)2CO + 6 HF → (CF3)2CO + 6 HCl

Hexafluoropropylene oxide rearranges to give HFA.

In the laboratory, HFA can be prepared in a two step process from perfluoropropene; in the first step KF catalyzes the reaction of the alkene with elemental sulfur to give the 1,3-dithete [(CF3)2CS]2. This species is then oxidized by iodate to give (CF3)2CO.[4]

Uses[edit]

Hexafluoroacetone is used in the production of hexafluoroisopropanol:

(CF3)2CO + H2 → (CF3)2CHOH

It is also used as a precursor to hexafluoroisobutene, (CF3)2C=CH2, a monomer.[3]

Reactivity[edit]

Hexafluoroacetone is an electrophile: nucleophiles easily attack at the carbonyl carbon. In water, hexafluoroacetone predominantly exists as the hydrate, the equilibrium constant (Keq) for the formation of this geminal diol is 106 M−1. The analogous equilibrium for acetone is an unfavorable 10−3 M−1.[5] Hexafluoroacetone-hydrates are acidic; in an analogous reaction, ammonia adds to hexafluoroacetone to give the hemiaminal (CF3)2C(OH)(NH2) which can be dehydrated with phosphoryl chloride to give the imine (CF3)2CNH.[6]

See also[edit]

References[edit]

  1. ^ a b c d e f "NIOSH Pocket Guide to Chemical Hazards #0319". National Institute for Occupational Safety and Health (NIOSH). 
  2. ^ CDC - NIOSH Pocket Guide to Chemical Hazards
  3. ^ a b Günter Siegemund, Werner Schwertfeger, Andrew Feiring, Bruce Smart, Fred Behr, Herward Vogel, Blaine McKusick (2002). "Fluorine Compounds, Organic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a11_349. 
  4. ^ Van Der Puy, M. ; Anello, L. G. (1990). "Hexafluoroacetone". Organic Syntheses.  ; Collective Volume, 7, p. 251 
  5. ^ Lemal, David M. (2004). "Perspective on Fluorocarbon Chemistry". The Journal of Organic Chemistry. 69 (1): 1–11. doi:10.1021/jo0302556. PMID 14703372. 
  6. ^ Middleton, W. J.; Carlson, H. D. (1988). "Hexafluoroacetoneimine". Organic Syntheses.  ; Collective Volume, 6, p. 664