Abstract Isobaric heat capacity, C P , of binary aqueous 1,2 − propanediol solutions have been measured over the temperature range from room temperature 298.15 K to 473.15 K at pressures up to 30 MPa using differential scanning calorimeter (DSC, ITS-400). The measurements were performed for three concentrations of 0.0731, 0.1914, and 0.4153 mol fraction of 1,2 − propanediol. The expanded uncertainty of the heat capacity ( C P ), pressure (P), temperature (T), and concentration (x) measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 2.4%, 0.05%, 15 mK, and 0.0001, respectively. The measured C P P T x data have been used to calculate excess molar heat capacities ( C Pm E ) of the mixture. The second temperature derivatives of specific volume or curvature of the Vm-T isobars have been calculated using the pressure dependence measured heat capacities along the isotherms as ∂ 2 V m / ∂ T 2 Px = - T - 1 ∂ C Pm / ∂ P Tx . Some unusual behaviour of C P in the low concentration range (below 0.2 mol fraction, dilute mixture) along the each measured isotherms-isobars was found.

中文翻译：

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二元液体（水 + 1,2-丙二醇）混合物在高温高压下的等压热容

摘要 使用差示扫描量热仪 (DSC, ITS-400) 在高达 30 MPa 的压力下，在室温 298.15 K 至 473.15 K 的温度范围内测量了二元 1,2 - 丙二醇水溶液的等压热容 CP 对 0.0731、0.1914 和 0.4153 摩尔分数的 1,2 - 丙二醇三个浓度进行了测量。在覆盖因子 k = 2 的 95% 置信水平下，热容 (CP)、压力 (P)、温度 (T) 和浓度 (x) 测量的扩展不确定性估计为 2.4%、0.05% 、 15 mK 和 0.0001，分别。测量的 CPPT x 数据已用于计算混合物的过量摩尔热容 (C Pm E )。Vm-T 等压线的比体积或曲率的二阶温度导数已使用压力依赖性测量的热容量沿等温线计算为 ∂ 2 V m / ∂ T 2 Px = - T - 1 ∂ C Pm / ∂ P Tx . 发现 CP 在低浓度范围（低于 0.2 摩尔分数，稀释混合物）中沿着每个测量的等温线-等压线的一些不寻常行为。