AbstractFive solvents of the β‐alkoxypropionitrile series have been studied by gas‐chromatography in order to examine their potential usefulness as solvents for extractive distillation. Four isomers of C4‐olefin and a diene were used as solutes for the determination of activity coefficients at infinite dilution at 30°C. Relative volatilities were calculated for these solvents and compared with those for other commercial solvents used currently. Relative volatilities of seven C4‐hydrocarbons in two solvents were also studied and compared with the existing literature data for β‐methoxypropionitrile containing 5% antisolvent. The present g.c. studies show that besides the well‐studied β‐methoxypropionitrile, the second member of the series, β‐ethoxypropionitrile, also has the potential for use as