Thermochemical behaviour of crown ethers in the mixtures of water with organic solvents - Part VII. Enthalpy of solution of 15-crown-5 and benzo-15-crown-5 in the mixtures of water with acetone at 298.15 K

摘要

Enthalpy of solution of crown ethers (15-crown-5 and benzo-15-crown-5) in water-acetone-mixtures have been measured within the whole range of mole fraction at 298.15 K. The obtained data have been compared with those of the solution enthalpy of both crown ethers in the mixtures of water with dimethyl suffoxide. The replacement of -S=O group with -C=O in the molecule of the organic solvent brings about an increase in the exothermic effect of the solution of 15-crown-5 and benzo-15-crown-5 ethers, especially in the mixtures with a medium water content. The observed effect is connected with the preferential solvation of the molecules of both crown ethers by acetone molecules in the water-acetone mixtures. The process of preferential solvation of 15-crown-5 and benzo-15-crown-5 ethers does not take place in the water-dimethyl sulfoxide mixture. (C) 2004 Elsevier B.V. All rights reserved.