拉曼光谱研究苯-重水间氢同位素分馏效应

摘要

Hydrothermal diamond-anvil cell and Raman spectrograph were used to measure the hydrogen isotope fractionation factor between benzene and heavy water at high P-T condition.The isotope fractionation factor is determined when the isotope fractionation between phases reached equilibrium.This research shows that hydrogen isotope fractionated easily between ben-ezene and water,different from hydrogen isotope fractionation betweenwater and n-alkanes or cycloalkanes.In this study,ben-zene was dispersed to many small particles,indicating the increasing contacting area to heavy water when temperature reached 300 ℃.Sufficient heating time enabled that stable isotope phases to reach the fractionation equilibrium.The ratio of Raman peak intensities and ratio of corresponding amount of substances is linearly correlated.The calculated hydrogen isotope fractionation factors between benzene and heavy water is 0.909 9 at 300 ℃.Taken together,it is feasible to determine the stable isotope frac-tionation factor between liquid phases with Hydrothermal Diamond-Anvil Cell combining with Raman spectroscopy.%应用金刚石压腔结合拉曼光谱技术研究了封闭体系内氢同位素在苯和重水之间的分馏效应.物相间达到同位素交换平衡是测定稳定同位素分馏系数的前提.与高温高压条件下水抑制正烷烃、环烷烃等烷烃的氢同位素分馏不同,苯的特殊结构可促使其在实验条件下与重水发生氢同位素分馏.通过逐步升高体系温度、增大苯和重水的接触面积、300 ℃下恒温足够长时间等实验手段促使苯和液态重水间达到氢同位素交换平衡,测得300 ℃条件下苯和重水之间的氢同位素分馏系数为0.9099.证明了原位拉曼技术测定不同液相间氢同位素分馏系数的可行性,同时扩展了金刚石压腔结合拉曼光谱技术测定不同物相间稳定同位素分馏系数的应用范围.