Abstract The specific ( c p ) and molar ( C p ) heat capacities of the mixtures of hexamethylphosphoramide (HMPA, or h) with water (w) have been measured using an adiabatic calorimetry at T = (283.15, 288.15, 293.15, and 298.15) K and ambient pressure. Based on the results obtained, the excess molar heat capacities of the mixtures, C p E , as well as apparent molar heat capacities of each component, C p , ϕ , i (down to its infinite dilution, C p , i ° ), have been calculated. The C p E values are positive up to HMPA mole fractions being xh ≈ 0.9 and the dC p E / d T derivative undergoes a positive-to-negative sign inversion at xh = 0.33. Both concentration and temperature dependences of C p , ϕ , i have also a complex character. The correlations of molar heat capacity properties with volume-related those for (H2O + HMPA) at the same temperatures have been discussed, too.

中文翻译：

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（水 + 六甲基磷酰胺）混合物的热力学：环境压力下 283.15 K 至 298.15 K 温度范围内的热容量特性

摘要 在 T = (283.15、288.15、293.15 和 298.15) 下，使用绝热量热法测量了六甲基磷酰胺 (HMPA，或 h) 与水 (w) 的混合物的比 (cp) 和摩尔 (Cp) 热容K 和环境压力。根据获得的结果，混合物的过量摩尔热容 C p E ，以及每个组分的表观摩尔热容 C p , ϕ , i （直至其无限稀释， C p , i ° ），已计算。C p E 值在 HMPA 摩尔分数为 xh ≈ 0.9 时为正，并且 dC p E / d T 导数在 xh = 0.33 处经历正负符号反转。C p , ϕ , i 的浓度和温度依赖性也具有复杂的特征。