507-20-0

colourless liquid

tert-Butyl chloride plays an important role as a starting material to perform nucleophilic substitution reactions in order to prepare alcohol and alkoxides salts. It is used as an alkylating agent for the introduction of tert-butyl group and is also involved in Friedel-Crafts reactions. It is employed as an intermediate for the synthesis of agrochemicals and pharmaceuticals.

Flammable

tert-Butyl chloride is prepared from tertbutyl alcohol (tert-butanol) using an acid catalyzed dehydration reaction.

The first step of the overall reaction is an acid-base reaction between the t-butanol and the hydrochloric acid. The t-butanol is a weak base and the hydrochloric acid is a strong acid. The alcoholic oxygen becomes fully protonated and so the equilibrium lies far to the right. In the second step we have the slow loss of water to form a carbocation intermediate. This species is very reactive and is immediately attacked by the chloride ion liberated in the first step to form tert-Butyl chloride.

Purification methods commonly used for other alkyl halides lead to decomposition. Some impurities can be removed by photochlorination with a small amount of chlorine prior to use. The liquid is washed with ice water, dried with CaCl2 or CaCl2 + CaO and fractionally distilled. It has been further purified by repeated fractional crystallisation by partial freezing. [Beilstein 1 IV 288.]