分子拓扑指数与链烷烃热力学性质的关系

The correlation between thermodynamic properties and molecular topological indexes of alkanes

碳原子个数N和路径数P3是表征链烷烃分子的大小、支化度和形状等结构特征的重要参数,引入烷烃所含甲基数的1.5次方M1和3次方M2表征取代基效应,运用多元线性模型研究了链烷烃标准生成焓、标准摩尔熵、标准生成吉布斯自由能等三种热力学性质与N,P3,M1和M2之间的定量关系,相关系数分别达到0.9993,0.9989和0.9972,标准偏差分别是2.2809kJ/mol,5.9093J/(mol·K),2.0585kJ/mol,其计算值与实验值非常接近.

The number (N) of carbon atoms and numbers of path 3 (P_3) are important parameters to characterize the size, branching and shape of alkanes. Two novel topological indexes (M_1 and M_2) have been introduced, m is the number of methyl groups of alkanes, M_1=m^(1.5),M_2=m^3. The quantitative relationships between N, P_3, M_1, M_2 and the three thermodynamic properties (ΔH~_f(g), S~(g), ΔG~_f(g)) of alkanes have been studied via multivariate linear model. The duplicate regression cofficients are excellent, the calculated value of the three thermodynamic properties of alkanes are in excellent agreement with the experimental values.