In order to investigate the effect of using 2-methyl-2,4-pentanediol as a co-solvent to 1,4-butanediol in the extraction of toluene from n-heptane, liquid–liquid equilibrium (LLE) phase compositions (tie-line data) were experimentally measured and thermodynamically modeled for the system n-heptane + toluene + 1,4-butanediol + 2-methyl-2,4-pentanediol at 298.2 and 313.2 K and 0.1 MPa. The direct analytical method was used to obtain the LLE data using a double-walled glass cell. The phase equilibrium samples were quantitatively analyzed using gas chromatography. The quaternary systems were successfully correlated using the NRTL and UNIQUAC thermodynamic models. Selectivity and solvent capacity were evaluated at various concentrations of co-solvent and compared to that of using pure 1,4-butanediol. The pseudo-ternary systems studied were found to demonstrate type II or type I phase behavior depending on temperature and co-solvent concentration. The presence of 2-methyl-2,4-pentanediol was found to have significantly improved solvent capacity at the cost of reduced selectivity.

中文翻译：

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使用 1,4-丁二醇 + 2-甲基戊烷-2,4-二醇液体混合物从正庚烷中液-液萃取甲苯

为了研究在从正庚烷中萃取甲苯中使用 2-甲基-2,4-戊二醇作为 1,4-丁二醇的助溶剂的效果，采用液-液平衡 (LLE) 相组成 (tie-线数据）对系统n进行了实验测量和热力学建模-庚烷 + 甲苯 + 1,4-丁二醇 + 2-甲基-2,4-戊二醇，298.2 和 313.2 K 和 0.1 MPa。直接分析方法用于使用双壁玻璃池获得 LLE 数据。使用气相色谱对相平衡样品进行定量分析。使用 NRTL 和 UNIQUAC 热力学模型成功地关联了四元系统。在不同浓度的共溶剂下评估选择性和溶剂容量，并与使用纯 1,4-丁二醇的情况进行比较。研究发现所研究的伪三元体系表现出 II 型或 I 型相行为取决于温度和助溶剂浓度。发现 2-甲基-2,4-戊二醇的存在以降低选择性为代价显着提高了溶剂容量。