POTASSIUM 2-METHYL-2-BUTOXIDE

Potassium tert-pentoxide is a colorless to light yellow liquid at room temperature and pressure, with strong alkalinity and a certain degree of hygroscopicity, and can undergo a more intense chemical reaction with water. Due to the large site resistance of alkyl group in its structure, its nucleophilicity is relatively poor, and it shows its strong alkalinity more often in organic synthesis chemistry.

Potassium tert-pentyloxide is used in wide range of applications in organic synthesis, agrochemicals, pharmaceuticals, colorants and aroma chemicals. It is also used in manufacturing detergents and biodiesel. They also act as catalysts in polymerization and isomerizations.

Potassium tert-pentoxide solution has been used as a base to synthesize [RuClPh(CO)(H₂IMes)(PCy₃)] from second-generation Grubbs metathesis catalyst, [RuCl₂(=CHPh)(H₂IMes)(PCy₃)], (where H₂IMes is 1,3-dimethyl-4,5-dihydroimidazol-2-ylidene and PCy₃ is tricyclohexylphosphine) and benzyl alcohol. This complex is a solid, air-stable and highly active isomerization catalyst.

The Preparative Method of Potassium 2-Methyl-2-butoxide: amber-coloured 0.15-0.20 M EtCMe2OH solutions of the reagent are prepared in situ by refluxing oxide-free potassium metal in the anhydrous alcohol for 3-4 h. Solutions of the base, which are 1.0-2.0 M in THF, benzene, or toluene, are prepared by treating oil-free Potassium Hydride with an equivalent amount of anhydrous t-pentyl alcohol in the anhydrous solvent under an inert atmosphere.

Solutions should be handled with the same precautions used for solutions of t-BuOK (see Potassium t-Butoxide). Avoid contact with the eyes, skin, and clothing. Conduct all reactions under a dry nitrogen or argon atmosphere. In the absence of air and moisture, solutions of the base in benzene or toluene may be stored in a refrigerator for up to 1 year without significant deterioration. However, for critical experiments, it is recommended that the reagent be freshly prepared. Use in a fume hood.