Difference between revisions of "Potassium tert-butoxide"
From Sciencemadness Wiki
| Line 59: | Line 59: | ||
| 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 = Hydrolyzes | ||
| − | | 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 = | + | | Solubility3 = 17.8 g/100 g (25 °C) |
| − | | Solvent3 = | + | | Solvent3 = tert-Butanol |
| − | | Solubility4 = 2.27 g/100 g (25 °C) | + | | Solubility4 = 25 g/100 g (25 °C) |
| − | | | + | | 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== | ||
| Line 128: | Line 135: | ||
==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 [[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== | ||
| Line 140: | Line 151: | ||
===Storage=== | ===Storage=== | ||
| − | + | 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 | + | Can be neutralized by adding it in plenty of water, then poured down the drain. |
==References== | ==References== | ||
Revision as of 17:04, 27 January 2018
| 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) |
| Hydrolyzes | |
| 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): | |
| LD50 (Median dose)
|
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)3CO−K+. It is a strong base (pKa of conjugate acid around 17), very useful in organic reactions.
Contents
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 tert-butanol.
- (CH3)3C-OH + K → (CH3)3CO−K+ + 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.
