The efficiency of industrial column packings is commonly tested by standard hydrocarbon mixtures. However, a reduced efficiency value is often observed, particularly during distillation of aqueous mixtures. In this paper, distillation experiments with various binary mixtures were carried out on different column packings to evaluate relative separation efficiencies of mixtures for each packing material. Each of the binary mixtures, which comprised heptane–methylcyclohexane, ethanol–water, morpholine–water, and acetic acid–water, was distilled under atmospheric pressure and total reflux ratio on column packings that were made of PTFE, ceramic, zirconium metal, and inox steel 316. According to the results, aqueous solutions of morpholine and acetic acid generally exhibited low relative separation efficiency (in comparison with standard mixture of heptane–methylcyclohexane), ranging between 40 % and 80 %. The highest relative efficiencies were observed with packings made of steel and ceramic. These observations will be useful for the future design of distillation columns, especially for aqueous solutions.