-
外観
白色～わずかにうすい黄色, 粉末又は塊
-
溶解性
水で分解, エタノールに可溶, アセトンに微溶。エタノールに溶け、アセトンに溶けにくく、水で分解する。
-
用途
有機合成(和光試薬時報Vol.66 No.2,p.21(1998))。
-
用途
カリウム tert-ブトキシド（カリウム ターシャリーブトキシド、potassium tert-butoxide）とは、有機化学で用いられる金属アルコキシドの一種。tert-ブトキシドアニオンとカリウムイオンからなる塩で、示性式は (CH3)3COK、あるいは tert-ブチル基を略して t-BuOK。吸湿性を持つ無色の粉末。立体的にかさ高い性質と有機溶媒への可溶性により、求核性の低い強塩基としてさまざまな有機合成に用いられる。
-
使用上の注意
アルゴン封入
-
化学的特性
white crystalline powder
-
使用
Potassium tert-Butoxide is used in the synthesis of many organic compounds primarily as a strong base. In particular, it is used as a reagent in the base- catalyzed carbonylation of amines for the synthesis of N-Formamides.
-
一般的な説明
This product has been enhanced for catalytic efficiency.
-
火災危険
Potassium tert-butoxide is a flammable solid.
It ignites on heating. Being very strongly
basic, its reactions with acids are highly
exothermic. Contact of solid powder with
drops of sulfuric acid and vapors of acetic
acid caused ignition after an induction period
of 0.5 and 3 minutes, respectively (Manwaring
1973). Ignition occurs upon reactions
with many common solvents of the
type ketone, lower alcohols, esters, and halogenated
hydrocarbons. Such solvents include
acetone, methyl ethyl ketone, methyl isobutyl
ketone, methanol, ethanol, n-propanol, isopropanol,
ethyl acetate, n-propyl formate,
n-butyl acetate, chloroform, methylene chloride,
carbon tetrachloride, epichlorohydrin,
dimethyl carbonate, and diethyl sulfate
(NFPA 1997). Such ignition may arise from
accidental contact of the alkoxide with these
solvents and may be attributed to sudden
release of energy from exothermic reactions.
However, slow mixing of the powder
with excess solvent will dissipate the
heat. It reacts violently with water, producing
tert-butanol and potassium hydroxide, as
follows:
K―OC―(C4H9)3＋H2O →
tert-C4H9OH +KOH
The addition of potassium tert-butoxide
to the solvent dimethyl sulfoxide can cause
ignition of the latter (Bretherick 1995).
-
純化方法
It sublimes at 220o/1mm. The last traces of tert-BuOH are removed by heating at 150-160o/2mm for 1hour. It is best prepared afresh as likely impurities are tert-BuOH, KOH and K2CO3 depending on its exposure to air. Its solubility at 25-26o in hexane, toluene, Et2O, and THF is 0.27%, 2.27%, 4.34% and 25.0%, respectively. [Feuer et.al. J Am Chem Soc 78 4364, Doering & Urban J Am Chem Soc 78 5938 1956, Beilstein 1 IV 1612.]
