Group contribution methods have been used to synthesise entrainers in the series, n-alkanes, aromatics, cycloalkanes and branched alkanes. The separation of ethanol from the synthesised entrainers depends on the size of a loop on the thermodynamic x-y diagram. Very easy separations are possible with hexane and 2,2-dimethylbutane, leading to high purity ethanol. A set of heuristic rules is proposed as a knowledge database to assist expert systems to identify the optimal entrainer.