Alcohols reactions with phosphorus trihalides.
(i) Alcohols react with liquid called phosphorus trichloride to make chloroalkanes. The reaction is given below:
(ii) Using phosphorus(III) bromide or iodide, the alcohol is usually heated under reflux with a mixture of red phosphorus and either bromine or iodine. First, the phosphorus reacts with the bromine or iodine to yield phosphorus(III) halide.
Then these furtherreact with the alcohol to give the corresponding halogenoalkane, that can be later separated by distillation.