HYDROGEN SOLUBILITY IN ORGANIC LIQUIDS
HYDROGEN SOLUBILITY IN ORGANIC LIQUIDS
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DOI：
10.1021/je00032a009
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发表时间：
1983-01-01
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影响因子：
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通讯作者：
SKLADMAN, L
中科院分区：
文献类型：
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作者：
HERSKOWITZ, M;WISNIAK, J;SKLADMAN, L
讨论从结果部分中给出的Xn（LK+）和X 0（K+）的平均值，发现比率X 0（LK+）等于0.54 in AN，0.56 s in PC，0.61 in DMF，0.53 in MeOH，0.81 in i-PrOH和0.60 in n-BuOH。与K+相比，LK+的迁移率明显降低，这是由于K+周围的溶剂化层被大体积配体部分取代所致。这种效应随溶剂的不同而变化，通过屏蔽LK+中K+上的电荷来促进，这是与冠的六个氧结合的结果。Takeda（22）对DMF中的18-冠-6 K+络合盐得出了相同的结论。当钾与体积较小的18-冠-6和二苯并-18-冠-6配体络合时，比与二叔丁基二苯并-18-冠-6络合时，离子迁移率的降低更小。在PC（23）中，比率Xn（18-cr-6 K+）/Xo（K+）= 8.91/11.17= 0.80，在DMF（22）中，比率Xn（18-cr-6 K+）/Xo（K+）= 24.6/30.8= 0.80，而在PC中，衍生自高氯酸盐的Xo（DB-18-cr-6 K+）/Xo（K+）为（25.80（24）-18.44（17））/11.17= 0.66。在甲醇中，该比率等于32.9/52.45= 0.62 g（25）。考虑到叔丁基苯并冠醚的非球形性质，LK+在各种溶剂中的溶剂动力学半径不能通过使用斯托克斯-爱因斯坦方程计算（对于二苯并-18-冠-6也是如此）。然而，可以注意到，X 0（LK+）t？0.15 g±0.2（表I）的离子强度与许多溶剂中正庚基铵离子的离子强度相当。溶剂化和接触离子对之间的关系，一方面和a的值将在随后的文件中讨论。
DiscussionFrom the average values of X „(LK+) and Xo (K+) presented in the Results section, the ratio Xofl-K+ yX^ K4") is found to be equal to 0.54 gin AN, 0.56 s in PC, 0.61 in DMF, 0.53 in MeOH, 0.81 in/-PrOH, and 0.60 in n-BuOH. The markedly decreased mo-bility of LK+ as compared to that of K+ must be ascribed to partial replacement of the solvation layer (s) around K+ by the bulky ligand. This effect, which varies with the solvent, is promoted by screening of the charge on K+ in LK+ as a con-sequence of binding to the six oxygens of the crown. Takeda (22) arrived at the same conclusion for the 18-crown-6 K+ complex salt in DMF. The reduction in ton mobility is less when potassium is complexed with the less bulky 18-crown-6 and dlbenzo-18-crown-6 ligands than with di-fert-butyldibenzo-18-crown-6. The ratio X „(18-cr-6 K+)/Xo (K+)= 8.91/11.17= 0.80 in PC (23) and 24.6/30.8= 0.80 in DMF (22), while in PC X0 (DB-18-cr-6 K+)/X0 (K+) derived from the perchlorate salt is (25.80 (24)-18.44 (17))/11.17= 0.66. In methyl alcohol this ratio is equal to 32.9/52.45= 0.62 g (25).The solvodynamic radius of LK+ in the various solvents cannot be calculated by using the Stokes-Einstein equation, considering the nonspherical nature of the fert-butylbenzo crown ether (the same is true for dibenzo-18-crown-6). However, it may be noted that the average value of X0 (LK+) t? of 0.15 g±0.2 (Table I) is comparable to that of n-heptyl-ammonium ion In many solvents. The relation between solvated and contact ion pairs on the one hand and the values of a will be discussed in a subsequent paper.