Difference between revisions of "Potassium tert-butoxide"

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| MolarMass = 112.21 g/mol
 
| MolarMass = 112.21 g/mol
 
| MeltingPt =  
 
| MeltingPt =  
| MeltingPtC = 256
+
| MeltingPtC = 256-258
 
| MeltingPt_ref =  
 
| MeltingPt_ref =  
 
| MeltingPt_notes = (decomposes)
 
| MeltingPt_notes = (decomposes)
 +
| Odor = Odorless
 
| pKa =  
 
| pKa =  
 
| pKb =  
 
| pKb =  
| Solubility = Hydrolyzes
+
| Solubility = Reacts
| SolubleOther = Soluble in [[tert-Butanol]], [[Tetrahydrofuran|THF]]<br>Slightly soluble in [[diethyl ether]], [[toluene]]<br>Poorly soluble in [[hexane]]
+
| SolubleOther = Reacts with [[acid]]s, [[carboxylic acid]]s, halocarbons<br>Soluble in [[tert-Butanol|''tert''-butanol]], [[Tetrahydrofuran|THF]]<br>Slightly soluble in [[diethyl ether]], [[toluene]]<br>Poorly soluble in [[hexane]]
 
| Solubility1 = 4.34 g/100 g (25 °C)
 
| Solubility1 = 4.34 g/100 g (25 °C)
 
| Solvent1 = diethyl ether
 
| Solvent1 = diethyl ether
 
| Solubility2 = 0.27 g/100 g (25 °C)
 
| Solubility2 = 0.27 g/100 g (25 °C)
 
| Solvent2 = hexane
 
| Solvent2 = hexane
| Solubility3 = 25 g/100 g (25 °C)
+
| Solubility3 = 17.8 g/100 g (25 °C)
| Solvent3 = tetrahydrofuran
+
| Solvent3 = tert-Butanol
| Solubility4 = 2.27 g/100 g (25 °C)
+
| Solubility4 = 25 g/100 g (25 °C)
| Solvent4 = toluene
+
| Solvent4 = tetrahydrofuran
 +
| Solubility5 = 2.27 g/100 g (25 °C)
 +
| Solvent5 = toluene
 
| VaporPressure =  
 
| VaporPressure =  
 
   }}
 
   }}
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==Properties==
 
==Properties==
 
===Chemical===
 
===Chemical===
 +
Potassium ''tert''-butoxide will readily hydrolyze in water to form tert-butanol and potassium hydroxide.
 +
 +
:(CH<sub>3</sub>)<sub>3</sub>COK + H<sub>2</sub>O → (CH<sub>3</sub>)<sub>3</sub>C-OH + KOH
 +
 
Potassium ''tert''-butoxide reacts exothermically with [[chloroform]].
 
Potassium ''tert''-butoxide reacts exothermically with [[chloroform]].
  
 
===Physical===
 
===Physical===
Potassium ''t''-butoxide is a colorless solid, which hydrolyzes in water, but has good solubility in organic solvents, like [[tetrahydrofuran|THF]].
+
Potassium ''t''-butoxide is a colorless solid, which hydrolyzes in water, but has good solubility in organic solvents, like tert-butanol, [[tetrahydrofuran|THF]].<ref>http://onlinelibrary.wiley.com/doi/10.1002/047084289X.rp198.pub2/abstract</ref>
  
 
==Availability==
 
==Availability==
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==Preparation==
 
==Preparation==
Potassium t-butoxide can be made by carefully adding metallic [[potassium]] to [[tert-Butanol|tert-butanol]]. Purification can be done via sublimation under vacuum.
+
Potassium t-butoxide can be made by carefully adding metallic [[potassium]] to dry [[tert-Butanol|tert-butanol]].
 +
 
 +
: (CH<sub>3</sub>)<sub>3</sub>C-OH + K → (CH<sub>3</sub>)<sub>3</sub>CO<sup>−</sup>K<sup>+</sup> + ½ H<sub>2</sub>
 +
 
 +
Purification can be done via sublimation under vacuum.
  
 
==Projects==
 
==Projects==
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===Storage===
 
===Storage===
In air-tight containers.
+
Potassium ''tert''-butoxide should be kept in dry air-tight containers, like [[Schlenk flask]]s or [[desiccator]]s.
  
 
===Disposal===
 
===Disposal===
Can be neutralized by adding it in plenty of water, then pour it down the drain.
+
Can be neutralized by adding it in plenty of water, then poured down the drain.
  
 
==References==
 
==References==
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[[Category:Chemical compounds]]
 
[[Category:Chemical compounds]]
 
[[Category:Organic compounds]]
 
[[Category:Organic compounds]]
[[Category:Sodium compounds]]
+
[[Category:Potassium compounds]]
 
[[Category:Alkoxides]]
 
[[Category:Alkoxides]]
 
[[Category:Tert-butoxides]]
 
[[Category:Tert-butoxides]]

Latest revision as of 20:21, 17 September 2022

Potassium tert-butoxide
Names
IUPAC name
Potassium 2-methylpropan-2-olate
Other names
Potassium t-butoxide
Potassium tert-butoxide
Potassium tert-butylate
Properties
C4H9OK
Molar mass 112.21 g/mol
Appearance Colorless to slight yellow solid
Odor Odorless
Melting point 256–258 °C (493–496 °F; 529–531 K) (decomposes)
Boiling point Sublimation begins from 220 °C (428 °F; 493 K) (at 1 mmHg)
Reacts
Solubility Reacts with acids, carboxylic acids, halocarbons
Soluble in tert-butanol, THF
Slightly soluble in diethyl ether, toluene
Poorly soluble in hexane
Solubility in diethyl ether 4.34 g/100 g (25 °C)
Solubility in hexane 0.27 g/100 g (25 °C)
Solubility in tert-Butanol 17.8 g/100 g (25 °C)
Solubility in tetrahydrofuran 25 g/100 g (25 °C)
Solubility in toluene 2.27 g/100 g (25 °C)
Hazards
Safety data sheet Sigma-Aldrich
Lethal dose or concentration (LD, LC):
690 mg/kg (rat, oral)
Related compounds
Related compounds
tert-Butanol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Potassium tert-butoxide is the chemical compound with the formula C4H9OK, sometimes written as (CH3)3COK+. It is a strong base (pKa of conjugate acid around 17), very useful in organic reactions.

Properties

Chemical

Potassium tert-butoxide will readily hydrolyze in water to form tert-butanol and potassium hydroxide.

(CH3)3COK + H2O → (CH3)3C-OH + KOH

Potassium tert-butoxide reacts exothermically with chloroform.

Physical

Potassium t-butoxide is a colorless solid, which hydrolyzes in water, but has good solubility in organic solvents, like tert-butanol, THF.[1]

Availability

Potassium tert-butoxide is sold by many chemical suppliers.

Preparation

Potassium t-butoxide can be made by carefully adding metallic potassium to dry tert-butanol.

(CH3)3C-OH + K → (CH3)3COK+ + ½ H2

Purification can be done via sublimation under vacuum.

Projects

  • Preparation of metallic potassium
  • Strong non-nucleophilic base in organic reactions
  • Ignition in contact with chloroform (or dichloromethane)

Handling

Safety

Potassium tert-butoxide is sensitive to water and is corrosive. Wear proper protection when handling the compound.

Storage

Potassium tert-butoxide should be kept in dry air-tight containers, like Schlenk flasks or desiccators.

Disposal

Can be neutralized by adding it in plenty of water, then poured down the drain.

References

  1. http://onlinelibrary.wiley.com/doi/10.1002/047084289X.rp198.pub2/abstract

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