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]]