离子在DMF-水混合溶剂中的体积性质

利用精密数字密度计测定了298．15K氯化氯化铵在N，N－二甲基甲酰胺（DMF）－水混合溶剂中的密度，计算了氯化钾及氯化铵的表观摩尔体积和极限偏摩尔体积，得到了相关离子的极限偏摩尔体积V′I^0和迁移偏摩尔体积△tV′i0，结果表明，当DMF浓度为15％－45％时，K^ 和NH4^ 的极限偏摩尔体积均表现增加趋势，而Cl^－的极限偏摩尔体积在同一DMF浓度范围内则表现为逐渐减小，利用溶质－溶剂和溶剂－溶剂相互作用对结果进行了讨论。

Volumetric properties of ions in DMF-water mixtures

Densities of KC1 and NH4C1 in several DMF-water mixtures were measured at 298. 15K with an oscillat-ing-tube densimeter. From these densities, apparent molar volumes and limiting partial molar volumes were calculated. Single-ion partial molar volumes of transfer from water to DMF-water mixtures were also obtained. The experimental result shows that the ionic partial molar volumes of K+ and NH4+ increase with increasing concentration of DMF in the range of 15% to 45%. On the contrary, the ionic partial molar volume of Cl- decreases with increasing concentration of DMF in the same region. The results were discussed on the basis of ion-solvent and solvent-solvent interactions.