Sodium tert-butoxide

Synthesis

Sodium tert-butoxide was synthesized using toluene or heptane as the solvent in the reaction system according to the following reaction formula:

In a 500mL reactor equipped with a stirrer, reflux condenser, and thermometer, 240mL of toluene or heptane (moisture content less than 0.04%) was added, along with 9.8g of 99% sodium amide (approximately 0.25mol) and 19.0g of 99% tert-butanol (approximately 0.254mol). The molar ratio of sodium amide to tert-butanol was 1:1.015. The mixture was stirred thoroughly until completely dissolved. The temperature was raised to 70℃ to initiate the reaction. The released ammonia gas was absorbed by water or alkaline solution. The reaction was stopped after the temperature was raised to 100-110℃ and maintained for 1 hour. After the reaction was fully and completely completed, the reactants were cooled. Most of the reaction medium and a slight excess of tert-butanol were distilled off under normal pressure. The remaining small amount of reaction medium was then distilled off under reduced pressure, yielding approximately 25g of a white solid powder. The product purity, as determined by acid-base titration, was above 99%.

Chemical Properties

white to light tan crystalline powder

Uses

Sodium tert-butoxide is used as a strong base and a non-nucleophilic base. In organic synthesis, it serves as an intermediate in various reactions like condensation, rearrangement and ring-opening. Further, it finds use in agrochemicals, pharmaceuticals, colorants, aroma chemicals, detergents and biodiesel. It acts as a catalyst in polymerization and isomerization reactions.

Flammability and Explosibility

Highly flammable

Purification Methods

Its solubility in tert-BuOH is 0.208M at 30.2o and 0.382M at 60o, and it is quite soluble in tetrahydrofuran (32g/100g). It should not be used if it has a brown colour. [Feuer J Am Chem Soc 78 4364 1956, Hurd Inorg Synth I 87 1939, IR: Seubold J Org Chem 21 156 1956, Beilstein 1 IV 1609.]