Apparent Molar Heat Capacities of n-Alcohols (C2 to C4) and Symmetric Tetraalkylammonium Bromides (C2 to C5) in Water–N,N-Dimethylformamide Mixtures: Methylene Group Contribution and Hydrophobic Hydration

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• 作者：W. Earle Waghorne ; Diana C. Riveros ; Edgar F. Vargas…
• 关键词：Heat capacity ; Alcohols ; Tetraalkylammonium bromides ; N ; N ; dimethylformamide ; Hydrophobic solvation
• 刊名：Journal of Solution Chemistry
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：45
• 期：9
• 页码：1303-1312
• 全文大小：560 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Physical Chemistry
  Industrial Chemistry and Chemical Engineering
  Geochemistry
  Oceanography
  Inorganic Chemistry
  Condensed Matter
  
• 出版者：Springer Netherlands
• ISSN：1572-8927
• 卷排序：45

文摘

The apparent molar heat capacities, ϕC_p, of ethanol, n-propanol, n-butanol, and tetraethylammonium, tetra-n-propylammonium, tetra-n-butylammonium and tetra-n-pentylammonium bromides have been measured measured using a Picker flow calorimeter (Sodev, Canada, Model CP-Cpr) at 298.15 K in water–N,N-dimethylformamide (DMF) mixtures. The contribution of the CH₂ moiety, ϕC_p(CH₂), was estimated from these data as the change in ϕC_p per additional CH₂ unit. The values of ϕC_p(CH₂) in water (ca. 100 J·K−1·mol−1) are two to three times those in neat organic solvents (ca. 30–40 J·K−1·mol−1), consistent with a substantial contribution from hydrophobic solvation in water. In water-rich aqueous DMF solutions, ϕC_p(CH₂) decreases monotonically with increasing DMF concentration, the decrease being more rapid for the n-alcohols. This trend differs significantly from that reported in the literature for highly aqueous mixtures of t-butanol, where ϕC_p(CH₂) passes through a maximum.