D₂O–H₂O solvent isotope effects on the enthalpy of 1,1,3,3-tetramethylurea hydration between 278.15 and 318.15 K

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• 作者：Dmitriy V. Batov ; Evgeniy V. Ivanov
• 关键词：1 ; 1 ; 3 ; 3-Tetramethylurea ; Ordinary and heavy water ; Enthalpies of solution
• 刊名：Thermochimica Acta
• 出版年：2010
• 出版时间：10 March 2010
• 年：2010
• 卷：500
• 期：1-2
• 页码：119-122
• 全文大小：196 K

文摘

The enthalpies of solution of 1,1,3,3-tetramethylurea in H₂O and D₂O were measured at 278.15, 288.15, 298.15, 308.15, and 318.15 K. Standard enthalpies and heat capacities of solution (hydration), along with D₂O–H₂O solvent isotope effects on the quantities studied, were computed. The enthalpies of the solute dissolution as well as corresponding solvent isotope effects were found to be negative in sign and decreasing in magnitude with increasing temperature. It was confirmed that hydrophobic hydration is the predominant type of the solute hydration and it is enhanced in D₂O and weakened on going from 1,1,3,3-tetramethylurea to its cyclic derivative, 1,3-dimethyl-2-imidazolidinone.