Specific retention volumes and limiting activity coefficients of C4-C8 alkane solutes in C22-C36 n-alkane solvents
Specific retention volumes and limiting activity coefficients of C4-C8 alkane solutes in C22-C36 n-alkane solvents
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DOI：
10.1021/je60065a015
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发表时间：
1975-04
影响因子：
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通讯作者：
J. Parcher;P. Weiner;C. Hussey;Theodore N. Westlake
中科院分区：
文献类型：
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作者：
J. Parcher;P. Weiner;C. Hussey;Theodore N. Westlake
在气液分配色谱中负责保留溶质的基本物理过程是一种或多种溶质在气相和液相之间的分配。因此，从正常（静态）溶解度或蒸气压测量中获得的大部分热力学信息也可以从气相色谱保留体积测量中获得。特别是，许多作者（1-4, 6, 8, 11, 14-19, 25, 26, 28, 31, 38, 39）测量了无限稀释活度系数和/或其他热力学数据，例如溶液热、溶液熵以及部分摩尔过量焓和熵。碳氢化合物系统已通过这种方法进行了广泛的研究。在较低温度（5、13、33、41）下测量了正十六烷、正十七烷和正十八烷中 C4-C8 烃溶质的活度系数。一些研究人员 (20, 32, 42, 45) 对较高温度 (> 60 C) 下 C20-C36 范围内的正构碳氢化合物进行了研究；然而，这些研究的范围有限，而且数据集几乎没有重叠。 Hicks 和 Young（20）研究了正丁烷、正戊烷和正己烷对正二十烷和正二十烷的影响；然而，每次测量都是在单独的温度下进行的，因此由于低温下低分子量溶剂的活度系数与温度相关，因此该数据几乎没有相关性。对于较高温度下的较高分子量系统，活度系数通常与温度无关，因为这些系统的部分摩尔过量焓值较低。然而，在较低温度下，活性系数通常随温度升高而降低；因此，不建议比较低分子量体系在不同温度下的数据集。 Martire 和 Rollara (32)、Young (45) 和 Tewari 等人 (42) 均报告了一种或多种溶剂在 80-120 C 范围内的活度系数数据，并且该文献数据将在讨论部分与本报告的结果进行比较。Pease 和 Thorburn (37) 已发表了 27 种烷烃溶质的正二十烷、正三十二烷和正二十烷的 Vg 数据。正十六烷在 80.0、100.0 和 120.0 C。这组 Vg 数据用作我们 Vg 值的参考点，比较将在讨论部分给出。
The basic physical process responsible for retention of a solute in gas-liquid partition chromatography is the par-tition of a solute or solutes between the gas and liquid phases. Because of this fact, much of the thermodynam-ic information attainable from a normal (static) solubility or vapor-pressure measurement is also obtainable from gas chromatographic retention volume measurements. In particular, numerous authors {1-4, 6, 8, 11, 14-19, 25, 26, 28, 31, 38, 39) have measured infinite dilution activity coefficients and/or other thermodynamic data such as heat of solution, entropy of solution, and partial molar excess enthalpies and entropies. Hydrocarbon systems have been studied extensively by this method. The activity coefficients of C4-C8 hydrocar-bon solutes in n-hexadecane, n-heptadecane, and n-oc-tadecane have been measured at lower temperatures (5, 13, 33, 41). The normal hydrocarbons in the range C20-C36 at higher temperatures (> 60 C) have been stud-ied by several investigators (20, 32, 42, 45); however, the studies have been limited in scope, and there is little overlap of the data sets. Hicks and Young (20) studied n-butane, n-pentane, and n-hexane on n-tetracosane and n-octacosane; however, each measurement was at a separate temperature so that little correlation of this data is possible because of the temperature dependence of the activity coefficients in low-molecular-weight solvents at low temperatures. For highermolecular-weight systems at higher temperatures, the activity coefficient is generally independent of temperature, because of low values for the partial molar excess enthalpy of these systems. However, at lower temperatures the activity coeffi-cients generally decrease with increasing temperatures; therefore, it is not advisable to compare data sets at different temperatures for low-molecular-weight systems. Martire and Rollara (32), Young (45), and Tewari et al.(42) all reportedactivity coefficient data for one or more solvents in the range80-120 C, and this literature data will be compared with the results of this report in the Discussion section.Pease and Thorburn (37) have published Vg data for 27 alkane solutes on n-octacosane, n-dotriacontane, and n-hexatriacontane at 80.0, 100.0, and 120.0 C. Thisset of Vg data was used as a reference point for our Vg values, and the comparison will be given in the Discus-sion section.