A study has been made of the selective and dissolving properties of new binary extractants - hydrocarbons based on 4-oxymethyl-1,3-dioxolane (with additions of diethylene glycol dimethyl and diethyl ethers) - under conditions of a gas-chromatographic experiment and in an extraction column. The thermodynamic functions of solvation have been determined and interpreted. Specific interaction in solvent-hydrocarbon systems has been assessed, and it has been shown that the selectivity of separation is determined by the contribution of pi-complexing energy to the partial molar free energy of solvation.