Apparent Molar Volumes and Adiabatic Compressibilities of Crown Ethers and Glymes in Aqueous Solutions at Various Temperatures

Apparent molar volumes and adiabatic compressibilities of 18-crown-6,15-crown-5, 12-crown-4, tetraglyme, and triglyme were measured at 15, 25, and40°C. Apparent molar expansibilities andK ^o Tvalues were also determined.The contribution of the -CH₂CH₂O- group to the limiting partial molar volumesand compressibilities of cyclic and open-chain ethers are compared. It isconcluded, on the basis of the compressibility results, that there is a subtle differencebetween the hydration of the ethene-oxide group in cyclic and open-chain ethers.