“Potassium fluoride”的意思、由来-开放百科全书

词条

Potassium fluoride

释义

Preparation
Applications in organic chemistry
Safety considerations
References

{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 464211515
| ImageFile = Potassium-fluoride-3D-ionic.png
| ImageSize =
| IUPACName = Potassium fluoride
| OtherNames =
|Section1={{Chembox Identifiers
| Abbreviations =
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 23006
| ChEMBL_Ref = {{ebicite|changed|EBI}}
| ChEMBL = 1644027
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 9082WG1G3F
| InChI = 1S/FH.K/h1H;/q;+1/p-1
| InChIKey = NROKBHXJSPEDAR-REWHXWOFAI
| SMILES = [F-].[K+]
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/FH.K/h1H;/q;+1/p-1
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = NROKBHXJSPEDAR-UHFFFAOYSA-M
| InChIKey1 = NROKBHXJSPEDAR-UHFFFAOYSA-M
| CASNo = 7789-23-3
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo_Comment = (anhydrous)
| CASNo2_Ref = {{cascite|changed|??}}
| CASNo2 = 13455-21-5
| CASNo2_Comment = (dihydrate)
| PubChem = 522689
| EINECS = 232-151-5
| RTECS = TT0700000
|Section2={{Chembox Properties
| Formula = KF
| MolarMass = 58.0967 g/mol (anhydrous)
94.1273 g/mol (dihydrate)
| Appearance = colourless
| Density = 2.48 g/cm³
| MeltingPtC = 858
| MeltingPt_notes = (anhydrous)
41 °C (dihydrate)
19.3 °C (trihydrate)
| BoilingPtC = 1502
| Solubility = anhydrous:
92 g/100 mL (18 °C)
102 g/100 mL (25 °C)

dihydrate:
349.3 g/100 mL (18 °C)
| SolubleOther = soluble in HF
insoluble in alcohol
| pKa =
| MagSus = −23.6·10⁻⁶ cm³/mol
|Section3={{Chembox Structure
| CrystalStruct = cubic
|Section7={{Chembox Hazards
| GHSPictograms = {{GHS06}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|301|311|331}}^[1]
| NFPA-H = 3
| NFPA-F = 0
| NFPA-R = 0
| NFPA-S =
| FlashPt = Non-flammable
| PEL =
| LD50 = 245 mg/kg (oral, rat)^[2]
|Section8={{Chembox Related
| OtherAnions = Potassium chloride
Potassium bromide
Potassium iodide
Potassium astatide
| OtherCations = Lithium fluoride
Sodium fluoride
Rubidium fluoride
Caesium fluoride
Francium fluoride
}}
}}

Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali halide and occurs naturally as the rare mineral carobbiite. Solutions of KF will etch glass due to the formation of soluble fluorosilicates, although HF is more effective.

Preparation

Potassium fluoride is prepared by dissolving potassium carbonate in excess hydrofluoric acid. Evaporation of the solution forms crystals of potassium bifluoride. The bifluoride on heating yields potassium fluoride:

K₂CO₃ + 4HF → 2KHF₂ + CO₂↑ + H₂O

KHF₂ → KF + HF↑

The salt must not be prepared in glass or porcelain vessels as HF and the aqueous solution of KF corrode glass and porcelain. Heat resistant plastic or platinum containers may be used.

Applications in organic chemistry

In organic chemistry, KF can be used for the conversion of chlorocarbons into fluorocarbons, via the Finkelstein reaction.^[3] Such reactions usually employ polar solvents such as dimethyl formamide, ethylene glycol, and dimethyl sulfoxide.^[4]

Safety considerations

Like other sources of the fluoride ion, F⁻, KF is poisonous, although lethal doses approach gram levels for humans. It is harmful by inhalation and ingestion. It is highly corrosive, and skin contact may cause severe burns.

References

1. ^{{cite web|url=https://www.sigmaaldrich.com/catalog/product/aldrich/449148?lang=en®ion=US|title=Potassium Fluoride|website=sigmaaldrich.com|accessdate=2018-12-20}}
2. ^{{cite web|url=http://chem.sis.nlm.nih.gov/chemidplus/rn/7789-23-3|title=ChemIDplus - 7789-23-3 - NROKBHXJSPEDAR-UHFFFAOYSA-M - Potassium fluoride - Similar structures search, synonyms, formulas, resource links, and other chemical information.|first=Michael|last=Chambers|date=|website=chem.sis.nlm.nih.gov}}
3. ^{{OrgSynth | author = Vogel, A. I.; Leicester, J.; Macey, W. A. T. | title = n-Hexyl Fluoride | collvol = 4 | collvolpages = 525 | prep = cv4p0525}}
4. ^Han, Q.; Li, H-Y. "Potassium Fluoride" in Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons,New York. {{doi|10.1002/047084289X.rp214}}

2 : Potassium compounds|Alkali metal fluorides

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