Effects of hydration on the thermodynamic properties of aqueous ethylene glycol ether solutions

Abstract

The densities and isobaric sp. heat capacities of binary mixts. of water with various open-chain and cyclic ethylene glycol ethers have been measured at 298.15 K using vibrating tube densitometry, and flow or differential scanning calorimetry, resp. Excess molar volumes were derived over the whole compn. range. Molar isobaric heat capacities and the relative apparent thermodn. quantities were detd. in the water-rich region. The data reflect the changes in the structure and hydrogen-bond dynamics of water caused by these non-ionic solutes. The obsd. effects are discussed in terms of the influence of hydrophobic hydration on the thermodn. properties of aq. solns. Correlations are given that enable the prediction of the thermodn. properties of open-chain and cyclic oligo(ethylene oxide) ethers in their pure liq. state and at infinite diln. in water.