The activity coefficients at infinite dilution of hydrocarbon solutes in 1,4-dicyanobutane have been measured using medium pressure gas-liquid chromatography. The hydrocarbon solutes were n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, 1-hexene, 1-heptene, 1-octene, 1-hexyne, 1-heptyne, 1-octyne, and benzene. The activity coefficients at infinite dilution were determined at T = (293.15, 298.15, and 303.15) K. The selectivities for benzene and the hydrocarbons are presented and the results indicate that 1,4-dicyanobutane is a good solvent for the separation of an alkane and benzene mixture. (C) 2000 Academic Press.