Fractional distillation is used for the separation of a mixture of two or more miscible liquids for which the difference in boiling points is less than 25K.e.g. CCl4 (Carbon tetrachloride) boiling point is 350K and anisole (boiling point is 427K can be separated by fractional distillation. The process involves heating the mixture and partial condensation of vapours along a column, which is ser up such that components with lower boiling points pass through the column and are collected earlier than components with higher boiling points.