Enthalpies of solvation of ethylene oxide oligomers CH3O(CH2CH2O)nCH3 (n = 1 to 4) in different H-bonding solvents: Methanol, chloroform, and water. Group contribution method as applied to t
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- 作者：Vladimir P. Barannikov ; ; ; vpb@isc-ras.ru ; Sabir S. Guseynov ; Anatoliy I. Vyugin
- 关键词：Solvation enthalpy ; Hydrogen bonding ; Additivity method ; Oligomers ; Ethylene oxide ; Glyme ; Solvents
- 刊名：Journal of Chemical Thermodynamics
- 出版年：2011
- 出版时间：December 2011
- 年：2011
- 卷：43
- 期：12
- 页码：1928-1935
- 全文大小：257 K
文摘
The enthalpies of solution and solvation of ethylene oxide oligomers CH3O(CH2CH2O)nCH3 (n = 1 to 4) in methanol and chloroform have been determined from calorimetric measurements at T = 298.15 K. The enthalpic coefficients of pairwise solute¨Csolute interaction for methanol solutions have been calculated. The enthalpic characteristics of the oligomers in methanol, chloroform, water and tetrachloromethane have been compared. The hydrogen bonding of the oligomers with chloroform and water molecules is exhibited in the values of solvation enthalpy and coefficient of solute¨Csolute interaction. This effect is not observed for methanol solvent. The thermochemical data evidence an existence of multi-centred hydrogen bonds in associates of polyethers with the solvent molecules. Enthalpies of hydrogen bonding of the oligomers with chloroform and water have been estimated. The additivity scheme has been developed to describe the enthalpies of solvation of ethylene oxide oligomers, unbranched monoethers and n-alkanes in chloroform, methanol, water, and tetrachloromethane. The correction parameters for contribution of repeated polar groups and correction term for methoxy-compounds have been introduced. The obtained group contributions permit to describe the enthalpies of solvation of unbranched monoethers and ethylene oxide oligomers in the solvents with standard deviation up to 0.6 kJ ¡¤ mol?. The values of group contributions and corrections are strongly influenced by solvent properties.