in presence of heat and light 1, 3-dichlorobutane is obtained with inversion of configuration.

For the reaction of CH₃OTs  + X^– → CH₃X  in the gas phase, the order of reactivity of halide ions is F^– > Cl^– > Br^– > I^–. But in methanol the order is reversed.

2-chloro-2-methyl propane is obtained as major product when 2-methyl propane reacts with Cl₂ in  Sunlight.

Direct halogenation of alkanes is not a good method of preparation of alkyl halides since this procedure gives mixture of isomers