Ultrasonic velocity, density and viscosity have been measured experimentally at 303.15 K in the six binary liquid mixtures of 1,4-dioxane (cyclic ether) with 1-methanol, 1-ethanol, 1-propanol, 1-butanol, 1-hexanol and 1-octanol and free volume as well as internal pressure were calculated for the six binary liquid mixtures of 1,4-dioxane with 1-alkanols at 303.15 K over the entire range of composition. Excess values of free volume and internal pressure have been calculated for these systems. The results were discussed in the light of existing theories of molecular interactions involved and chemical composition of the liquid components.