论文部分内容阅读
129XeNMR可以作为研究液体结构状态的探针．甲醇是一个与水结构差别最小的有机溶剂．本文研究了129Xe在甲醇-丁醇，甲醇-戊醇，甲醇-辛醇，甲醇-癸醇混合溶剂中化学位移随组成的变化，并测定了混合溶剂的密度和折射率．129Xe化学位移随混合溶剂的摩尔分数的变化为四条曲率很近的曲线，而化学位移随混合溶剂的体积分数的变化为斜率随多碳醇碳原子数增加的直线．这表明甲醇-多碳醇二元混合溶剂中不存在疏溶剂作用，而构成分子均匀分布的体系．129Xe在甲醇-丁醇，甲醇-癸醇中的化学位移与混合溶剂折射率的一种函数的关系为两条斜率很接近的直线，表明Xe在溶液中主要受范德华力作用．
129XeNMR can be used as a probe to study the state of liquid structure. Methanol is a minimally different organic solvent from water. In this paper, the chemical shifts of 129Xe in methanol-butanol, methanol-amyl alcohol, methanol-octanol and methanol-decanol mixed solvents were investigated. The density and refractive index of the mixed solvents were measured. The change of 129Xe chemical shift with the change of the mole fraction of the mixed solvent is four curves with very close curvatures. The change of the chemical shift with the volume fraction of the mixed solvent is a straight line with a slope increasing with the number of carbon atoms of the polycarbonic alcohol. This shows that there is no solvating agent in the methanol-polyhydric alcohol binary mixed solvent, which constitutes a homogeneous distribution system of molecules. The chemical shift of 129Xe in methanol-butanol and methanol-decanol is a function of the refractive index of the mixed solvent as a straight line with two slopes very close to each other, indicating that Xe is mainly affected by van der Waals forces in solution.