Densities of pure 1-butyl-3-methylimidazolium methylsulfate, [C4mim][MeSO4], and its mixtures with methanol have been measured. Measurements were made with an accuracy of ±0.2 kg·m−3, using a vibrating-tube densimeter, over the temperature and pressure ranges (283.15–333.15) K and (0.1–35) MPa, respectively. The experimental densities for the pure ionic liquid and alcohol have been correlated by the Tait equation. The results for the {x1[C4mim][MeSO4] + (1 − x1)MeOH} system have been correlated by a van Laar equation involving parameters that are dependent on temperature and pressure. Excess volumes have been obtained directly from the experimental densities, while isobaric expansivities, isothermal compressibilities, and related excess properties were calculated from the correlation equation. Exceptionally strong pressure and temperature influences on these properties were observed.

中文翻译：

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{x 1[C4mim][MeSO4] + (1 − x 1)MeOH} 系统在 (283.15 到 333.15) K 的温度和 (0.1 到 35) MPa 的压力下的体积特性

已测量纯 1-丁基-3-甲基咪唑鎓甲基硫酸盐 [C4mim][MeSO4] 及其与甲醇的混合物的密度。使用振动管密度计，分别在 (283.15–333.15) K 和 (0.1–35) MPa 的温度和压力范围内以 ±0.2 kg·m-3 的精度进行测量。纯离子液体和酒精的实验密度已通过 Tait 方程相关联。{x1[C4mim][MeSO4] + (1 − x1)MeOH} 系统的结果已通过范拉尔方程相关联，该方程涉及依赖于温度和压力的参数。过量体积是直接从实验密度获得的，而等压膨胀率、等温压缩率和相关的过量特性是从相关方程计算出来的。