Fluoroform
2814674
221284285
2008-06-23T21:15:31Z
DOI bot
6652755
Citation maintenance. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]].
{{Chembox new
| ImageFileL1 = Fluoroform.svg
| ImageFileR1 = Fluoroform-3D-vdW.png
| IUPACName = Trifluoromethane
| OtherNames = Fluoroform, Carbon trifluoride, Methyl trifluoride, Fluoryl, Freon 23, Arcton 1, HFC 23, R-23, [[FE-13]], UN 1984
| Section1 = {{Chembox Identifiers
| CASNo = 75-46-7
| EINECS = 200-872-4
| PubChem = 6373
| SMILES = C(F)(F)F
| InChI = 1/CHF3/c2-1(3)4/h1H
| RTECS = PB6900000
| ChEBI = 24073
}}
| Section2 = {{Chembox Properties
| Formula = CHF<sub>3</sub>
| MolarMass = 70.01 g/mol
| Appearance = Colorless gas
| MeltingPt = -155.2 °C (117.95 K)
| BoilingPt = -82.1°C (191.05 K)
| Solubility = 1 g/l
| SolubleOther = Soluble
| Solvent = organic solvents
| VaporPressure = 4.38 MPa at 20 °C
| HenryConstant = 0.013 mol.kg<sup>-1</sup>.bar<sup>-1</sup>
| pKa = 25 - 28
}}
| Section3 = {{Chembox Structure
| CrystalStruct =
| Coordination =
| MolShape = [[Tetrahedral]]
}}
| Section3 = {{Chembox Hazards
| MainHazards = Nervous system depression
| SPhrases = {{S38}}
| NFPA-H = 1
| NFPA-F = 0
| NFPA-R = 0
| NFPA-O =
| FlashPt = Non-flammable
| Autoignition =
}}
}}
'''Fluoroform''' is the [[chemical compound]] with the formula CHF<sub>3</sub>. It is one of the "[[trihalomethane|haloforms]]", a class of compounds with the formula CHX<sub>3</sub> (X = [[halogen]]). Fluoroform is used in diverse niche applications and is produced as a by-product of the manufacture of [[Teflon]]. Fluoroform is also generated biologically in small amounts apparently by [[decarboxylation]] of trifluoroacetic acid.<ref>Kirschner, E., Chemical and Engineering News 1994, 8.</ref>
==Additional physical properties==
{| class="wikitable"
! Property
! Value
|-
| [[Density]] (ρ) at -100 °C (liquid)
| 1.52 g/cm<sup>3</sup>
|-
| [[Density]] (ρ) at -82.1 °C (liquid)
| 1.431 g/cm<sup>3</sup>
|-
| [[Density]] (ρ) at -82.1 °C (gas)
| 4.57 kg/m<sup>3</sup>
|-
| [[Density]] (ρ) at 0 °C (gas)
| 2.86 kg/m<sup>3</sup>
|-
| [[Density]] (ρ) at 15 °C (gas)
| 2.99 kg/m<sup>3</sup>
|-
| [[Dipole moment]]
| 1.649 D
|-
| [[Critical pressure]] (p<sub>c</sub>)
| 4.816 MPa (48.16 bar)
|-
| [[Critical temperature]] (T<sub>c</sub>)
| 25.7 °C (299 K)
|-
| [[Critical density]] (ρ<sub>c</sub>)
| 7.52 mol/l
|-
| [[Compressibility factor]] (Z)
| 0.9913
|-
| [[Acentric factor]] (ω)
| 0.26414
|-
| [[Viscosity]] (η) at 25 °C
| 14.4 μPa.s (0.0144 cP)
|-
| [[Specific heat capacity|Molar specific heat]] at constant volume (C<sub>V</sub>)
| 51.577 J.mol<sup>-1</sup>.K<sup>-1</sup>
|-
| [[Latent heat of vaporization]] (l<sub>b</sub>)
| 257.91 kJ.kg<sup>-1</sup>
|-
|}
==Industrial applications==
CHF<sub>3</sub> is used in the [[semiconductor]] [[industry]] in [[plasma etching]] of [[silicon oxide]] and [[silicon nitride]].
As a [[refrigerant]], CHF<sub>3</sub> is known as R-23 or HFC-23.
HFC-23 is also used as a replacement for [[Halon 1301]][cfc-13b1] in [[fire suppression system]]s as a total flooding [[gaseous fire suppression]] agent. It is also used as a low temperature refrigerant (replacement for [[Chlorotrifluoromethane]] (cfc-13). It is a byproduct of its manufacture. When used as a fire suppressant, the chemical carries the [[DuPont]] trade name, [[FE-13]]. CHF<sub>3</sub> is recommended for this application because of its low toxicity, its low reactivity, and its high density.
CHF<sub>3</sub> is a potent [[greenhouse gas]]. The secretariat of the Clean Development Mechanism estimates that a ton of HFC-23 in the atmosphere has the same effect as 11,700 tons of carbon dioxide. The atmospheric lifetime is 260 years.<ref>{{cite journal
|title=Refrigerant Data Summary
|journal=Engineered Systems
|volume= 18
|pages=74–88
|year= 2001}}</ref>
According to researchers, it is the most abundant of [[hydrofluorocarbons]] (HFCs). Its usage has been regulated since December 1997 at ''Kyoto climate conference''.
==Chemistry==
It was first obtained by Meslans in the violent reaction of [[iodoform]] with dry [[silver fluoride]] in 1894. <ref>{{cite journal
| title = .
| author = Meslans M. M.
| journal = [[Annales de chimie et de physique]]
| year = 1894
| volume = 7
| issue = 1
| pages = 346–423
| url = http://gallica.bnf.fr/ark:/12148/bpt6k34901c/f344.table
}}</ref> The reaction was improved by [[Otto Ruff]] by substitution of silver fluoride by a mixture of [[mercury fluoride]] and [[calcium fluoride]].<ref>{{cite journal
| title = Fluoroform
| author = Henne A. L.
| journal = [[Journal of the American Chemical Society]]
| year = 1937
| volume = 59
| issue = 7
| pages = 1200–1202
| doi = 10.1021/ja01286a012
}}</ref> The exchange reaction works with iodoform and [[bromoform]], and the exchange of the first two [[halogen]] atoms by fluorine is vigorous. By changing to a two step process, first forming a bromodifluoro methane in the reaction of [[antimony trifluoride]] with bromoform and finishing the reaction with mercury fluoride the first efficient synthesis method was found by Henne.<ref>{{cite journal
| title = Fluoroform
| author = Henne A. L.
| journal = [[Journal of the American Chemical Society]]
| year = 1937
| volume = 59
| issue = 7
| pages = 1200–1202
| doi = 10.1021/ja01286a012
}}</ref>
==Organic chemistry==
CHF<sub>3</sub> is a reagent to generate CF<sub>3</sub><sup>-</sup> reagents by deprotonation. The molecule is weakly acidic with a pKa = 25–28. It is a precursor to CF<sub>3</sub>[[trimethylsilyl|Si(CH<sub>3</sub>)<sub>3</sub>]]<ref>Rozen, S.; Hagooly, A. "Fluoroform" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. {{DOI| 10.1002/047084289}}</ref>
==See also==
* [[Haloalkane]]
* [[Halomethane]]
* [[Trihalomethane]]
* [[Fluoromethane]]
* [[Difluoromethane]]
* [[Tetrafluoromethane]]
* [[Chloroform]]
* [[Bromoform]]
* [[Iodoform]]
==References==
<references/>
*{{cite journal
| title = Fluorine Chemistry
| author = McBee E. T.
| journal = [[Industrial & Engineering Chemistry]]
| year = 1947
| volume = 39
| issue = 3
| pages = 236–237
| doi = 10.1021/ie50447a002
}}
*{{cite journal
| title = Growth of fluoroform (CHF<sub>3</sub>, HFC-23) in the background atmosphere
| author = Oram D. E., Sturges W. T., Penkett S. A., McCulloch A., Fraser P. J.
| journal = [[Geophysical Research Letters]]
| year = 1998
| volume = 25
| issue = 1
| pages = 236–237
| url = http://www.agu.org/pubs/crossref/1998.../97GL03483.shtml
| doi = 10.1029/97GL03483
}}
*{{cite journal
| title = Fluorocarbons in the global environment: a review of the important interactions with atmospheric chemistry and physics
| author = McCulloch A.
| journal = [[Journal of Fluorine Chemistry]]
| year = 2003
| volume = 123
| issue = 1
| pages = 21–29
| doi = 10.1016/S0022-1139(03)00105-2
}}
==External links==
* {{ICSC|0577|05}}
* [http://ptcl.chem.ox.ac.uk/MSDS/TR/trifluoromethane.html MSDS at Oxford University]
* [http://www.mathesontrigas.com/pdfs/msds/MAT09970.pdf MSDS at mathesontrigas.com]
* [http://rsc.org/delivery/_ArticleLinking/DisplayArticleForFree.cfm?doi=a801406j&JournalCode=CC Coupling of fluoroform with aldehydes using an electrogenerated base]
[[Category:Organofluorides]]
[[Category:Halomethanes]]
[[Category:Refrigerants]]
[[de:Fluoroform]]
[[pl:Trifluorometan]]