трет-Бутилат калия

Химические свойства

white crystalline powder

Использование

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.

Общее описание

This product has been enhanced for catalytic efficiency.

Пожароопасность

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).

Применение

трет-Бутилат калия имеет широкое применение в органическом синтезе как сильное основание для проведения реакций замещения, присоединения и изомеризации.

Также калия трет-бутоксид используется как реагент, например при получении алкил или арил трет-бутиловых эфиров.

Методы очистки

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.]