链烷烃分子结构特征与熔点的变化关系

Relationship between the structural characteristics and melting-point for paraffin

在分析链烷烃的分子结构特征基础上 ,根据分子热力学中的Lennard -Jones势能函数式 ,提出了链烷烃的熔点计算模型 ,以正癸烷和 4种主链碳原子数分别为 4、5、6、7的支链烷烃为模型化合物进行相关分析 ,得出模型方程 ,将其用于 30种含碳原子数为 2 - 31的直链烷烃和 4 8种主链碳原子数为 4 - 7的支链烷烃的熔点进行估算 ,平均绝对误差为 4 .70℃ ,平均相对误差为 2 .5 9% 。

Based upon the equation of the Lennard-Jones potential, it was modeled the relation between the structural characteristics and melting-point for paraffin. The multiple regression analysis (MRA)correlating melting point with the three parameters was carried out by taking decane, 2,2-dimethylbutane, 2,4-dimethylpentane,2,2-dimethylhexane,and 2,6-dimethylheptane as model compounds. The expression was obtained with the correlation coefficient r = 0.9996 and standard deviation s = 1.46℃. Using the obtained expression, the melting points of 78 paraffin were estimated. It's mean absolute error between experimental and calculated values is only 4.70℃, and the mean relative error is 2.59%.