Fractional distillation allows the separation of pure compounds from complex mixtures based on the components boiling point. Each compound evaporates up the glass distillation column when the temperature of the boiling pot containing the sample reaches the compounds boiling point. After exiting the distillation column, the compound flows down a condenser and collects at the end. Fractional distillation always endeavors to achieve high purity of the fractions collected. You can improve the purity of the fraction by increasing the surface area of the fractionation column.
Remove the fractionation column from the distillation unit and pack the internal space with steel wool. The steel wool increases the surface area the vapors interact with and slows the movement of the vapors up the column. The longer the vapors take to reach the top of the column, the higher the purity of the fraction and the greater the efficiency of the column. You can use any highly porous, non-absorbent material for the column packing material.
Raise the temperature of the heat source slowly to give the fractions time to interact and complete their movement up the column and down the condenser arm. Many industrial manufacturers increase the surface area in the column to recover fractions that have a boiling point separated by less than a degree.
Wrap the distillation column with an insulator like aluminum foil. The insulation will allow the vapors to travel all the way to the top of the column and out the condenser. The increase in efficiency results from the repeated interaction with the column packing. The vapor condenses on the metal and drops back to the boiling pot to evaporate again.