多氯联苯分子结构参数与色谱焓、熵变化的定量关系

Quantitative Relationship Between Molecular Structure of Polychlorinated Biphenyls (PCBs) and Enthalpy Change (ΔH), Entropy Change (ΔS′) in Chromatographic Process

通过理论分析与研究,提出了描述多氯联苯(PCBs)氯原子数目与取代位置有关的分子拓扑指数结构参数JG以及描述多氯联苯分子中氯原子之间相邻关系的分子拓扑指数邻接参数LJ,并推导出PCBs在色谱过程中的焓变(ΔH)、似溶解熵变(ΔS')与结构参数JG、邻接参数LJ的关系式.在DB-1,DB-5,DB-1701等3种固定相上测定了140余种PCB的ΔH、ΔS'数值,并运用所推导出的关系式对ΔH和ΔS'进行了预测,收到良好的效果,ΔH和ΔS'的理论计算值与实验值的平均相对偏差分别为0.56% ～0.97%和0.55% ～1.06% ,接近实验数据本身的相对偏差.

The relationship between the rule of chromatographic retention value and molecular structure is an important part in the research of chromatographic thermodynamics. The topological index structural parameter JG and the topological index adjoining parameter LJ are put forward. Parameter JG describes the correlation of quantity and position of chlorine atoms in polychlorinated biphenyl （PCB） molecules. Parameter LJ describes the ortho-position correlation of chlorine atoms in PCB molecules. The relational expression between the PCB molecular structures and their enthalpy change （ ΔH）, entropy change （ΔS＇） in chromatographic process was discovered. The values of enthalpy change and entropy change for about 140 kinds of polychlorinated biphenyls in chromatographic process on three stationary phases, DB-1, DB-5 and DB- 1701, were determined. In comparison with ΔH and ΔS＇ of the experimental data those calculated from the relational expression had the average relative deviations for ΔH and ΔS＇ are 0.56% -0. 97% and 0.55% - 1.06%, respectively.