Question

ORGANIC CHEMISTRY

experiment : Synthesis of n-butyl bromide (Sn2)

1.what is the function of the Hickman Still in this experiment?

2. what is the function of the condenser in this experiment?

Answer 1

n-Butyl bromide is a primary alkyl halide which can be prepared by S_N2 reaction between 1-Butanol and Sodium bromide in the presence of sulphuric acid.

In this experiment, HBr is generated in the reaction mixture by treatment of NaBr with H₂SO₄.

This reaction is carried out by the process of distillation using a special apparatus called Hickman distilling head.

1) Hickman distilling head is a large device and requires connecting. The purpose of Hickman still is to heat the liquid until it passes into vapour phase. Then it allows the vapours to cool and condense back into the liquid phase. The condensed liquid gets trapped in the other container. When the mixture of alcohol, NaBr and sulphuric acid is heated, the vapours of HBr are given off which are quite toxic as well as corrosive. Thus, these vapours must be trapped. The function of Hickman still in this reaction is to trap these vapours.

2) Condenser is mainly used for refluxing the reaction mixture. It prevents the solvent from boiling away as the reaction mixture is continuously heated and the reaction continues.