Thermodynamic properties of binary mixtures involving sulfolane. 1. Excess volumes on mixing sulfolane and propionitrile, butyronitrile, and valeronitrile

Excess volumes on mixing sulfolane and propionitrile, butyronitrile, and valeronitrile were measured over the entire composition range 0 <= × <= 1, at four temperatures between 293.1 and 323.1 K. All mixtures exhibit negative excess volumes with a minimum which occurs approximately at × = 0.5 in the case of the butyronitrile-sulfolane and valeronitrile-sulfolane systems; it is shifted toward the propionitrile-rich region in the case of the propionitrile-sulfolane system. The magnitude of the minimum steadily increases with temperature and decreasing nitrile chain length. Data are interpreted in terms of moderate interactions of all kinds decreasing in importance with increasing nitrile carbon chain length and an increase of the nitrile self-association with respect to the interactions with sulfolane as the temperature increases. © 1982 American Chemical Society.