Enthalpies of dilution of alkaline and alkaline earthp-toluenesulfonates-猫眼课题宝

碱金属和碱土金属对甲苯磺酸盐的稀释焓

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1996

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K. O. Debevc;C. Pohar;V. Vlachy

对甲苯磺酸的锂、钠、钾、铯、钙、镁和锶盐的水溶液的稀释焓（ΔHD，c→0.002 mol-dm−3）在0° C和40°C之间的几个温度下测量，并且在宽的浓度范围内。结果表明：（1）对甲苯磺酸锂的稀释焓随浓度的增加而增大，而钠、钾和铯盐的稀释焓均出现最大值;（2）稀释焓与阳离子的离子半径密切相关，稀释焓的-ΔHD值按Li>Na>K>Cs的顺序增大。这与碱性聚（苯乙烯磺酸盐）溶液中相同量的行为相似。对于二价离子的情况是不同的，镁，钙，锶对甲苯磺酸盐表现出很小的温度依赖性和几乎没有依赖性的离子的性质。与聚（苯乙烯磺酸盐）的解决方案相比，稀释的放热的所有温度和盐。

Enthalpies of dilution (ΔHD, c→0.002 mol-dm−3) of aqueous solutions of lithium, sodium, potassium, cesium, calcium, magnesium, and strontium salts of p-toluenesulfonic acid were measured at several temperatures between 0° and 40°C, and over a broad concentration range. For monovalent ions the following results were obtained: (i) the enthalpy of dilution for lithium p-toluenesulfonate became more exothermic on increasing the concentration, while those of sodium, potassium, and cesium salts exhibited a maximum, (ii) enthalpies of dilution were strongly dependent on the ionic radius of the cation, and the-ΔHD values increase in the order, Li>Na>K>Cs. This parallels the behavior of the same quantity in alkaline poly(styrenesulfonate) solutions. For divalent ions the situation was different; Mg, Ca, and Sr p-toluenesulfonates showed little temperature dependence and almost no dependence on the nature of the ion. In contrast with poly(styrenesulfonate) solutions, the enthalpies of dilution were exothermic for all temperatures and salts.

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