Butane can be prepared from ethyl chloride using the following synthesis The reaction is

Step-by-step solution

Here an alkyl halide is first converted to lithium dialkyl cuperate, R 2 CuLi , which on reaction with alkyl halide gives an alkane. This method is also suitable for the preparation of unsymmetrical alkane of the type R − R ′ , where R ≠ R ′ .