Apparent Molar Volumes and Adiabatic Compressibilities of Crown Ethers and Glymes in H_2O and D_2O at 25 deg C

摘要

The apparent molar volllme~ and adiatlatic compressibi.lities of 18-Crown-6, 15-Crown- 5, 12-Crown-4. tetraglyme. and triglyme were measlll-ed at 25°C in H20 and D20. The contribution of the -CH2CH20- group t(1 the limiting partial molar volumes and compre~sibiljties of cyclic and open-chain ethers in t'It)th solvents are compared and solvent isotope effects calculated. It is concluded. based (1n the c(1mpressibility results. that tltere is a subtle difference between the hydration (1f the ethene oxide group in cyclic and open-chain ethers and tltat this difference )f:rsi5ts in D20. These results indicate thaI the calculation of limiting apparent molar c(1mpressibilities using additivity s...hemes will have to account for whether the group is in a cyclic or open-chain compound.