EXCESS MOLAR ENTHALPIES AND EXCESS MOLAR VOLUMES OF PROPYLENE CARBONATE PLUS CYCLIC ETHERS

Excess molar enthalpies, H-m(E), and excess molar volumes, V-m(E), have been determined as a function of-mole fraction for propylene carbonate + oxane, oxolane, 1,4-dioxane, and 1,3-dioxolane at 298.15 K and at atmospheric pressure in a now microcalorimeter and in a digital density meter. The experimental values have been correlated using the Redlich-Kister equation, and the parameters;have been evaluated by least-squares analysis. The H-m(E) values are positive for the propylene carbonate + oxane and oxolane mixtures and negative in the mixture with 1,3-dioxolane, while inversion of sign has been noted for the propylene carbonate + 1,4-dioxane mixture. The H-m(E), values range from a minimum of -170 J mol(-1) to a maximum of 480 J mol(-1); The V-m(E) values are all negative with a minimum varying from -0.21 up to -0.34 cm(3) mol(-1) in the order dioxane < oxane < dioxolane < oxolane.