用图论方法预测饱和烷烃的偏心因子

利用约化Wiener指数Wc 以及路径数P2 、P3 研究了饱和烷烃偏心因子ω与分子的拓扑结构关系 ,结果表明分子体积是决定分子偏心度的主要因素 ,而分子的支化和形状在一定程序上也影响分子的偏心度。通过建立ω与Wc、P2 、P3 之间的QSPR模型 ,提出了一种直接从分子的拓扑结构预测烷烃偏心因子的简便方法。对 5 1个烷烃计算值与实验值的平均偏差仅为 0 .0 0 44。并对部分烷烃的偏心因子进行了预测。预测值与文献值十分一致。

Prediction of Paraffin Eccentric Factors by Graph Theory

Both the reduced Wiener index Wc and path numbers P1，P2 were used to correlate with Pitzer eccentric factors ω of paraffin.The results showed that the molecular volume or size was a main factor determining the eccentric degree.However,the molecular branching,shape,etc.,had also small effects on molecular eccentric degree.A quantitative structure property relationship (QSPR) between Wc，P1，P andω was established and used to directly estimate ω of paraffin from their topological structures.The calculated values were in satisfactory agreement with experimental data.The absolute average deviation between calculated values and experimental data was 0.0044 for 51 alkanes.The eccentric factors of some alkanes were predicted based on the QSPR model and compared favorably with literature data.The predicted values were in good agreement with literature data.