松香枞酸结构和性质的理论研究

Theoretical Investigation on Structure and Property of Abietic Acids in Rosin

采用从头算Hartree-Fock和密度泛函DFT方法对松香枞酸分子的几何构型进行理论计算,按最低能量原理确定其最稳定的构型。对该稳定构型的结构参数与文献报道的理论计算值和试验测定值进行分析比较,发现3种理论方法中DFT-B3LYP算法更加精确,与实际测量值的误差更小,更加适合用于对此类化合物的分析与预测。同时用B3LYP泛函在6-31 +G**机组水平对松香的几种主要树脂酸进行能量分析,预测其稳定性并得到相应的热力学参数。结果表明:计算化学方法也是科学研究的一种有用工具,精确的理论计算能够获得实验室难于得到的重要的化学与物理信息,理论计算也可作为研究该类体系的一种新方法。

The geometry of abietic acid has been investigated by several theoretical methods including the Hartree-Fock and DFF-B3LYP level of ab initio theory. Its most stable structure is determined by the minimum energy. Comparing with the known experimental results, DFT-B3LYP which has the smallest error in three theoretical methods is the best one for analysis and predication of these systems. In the mean time, the relative energies of four resin acids in rosin were analysized by the B3LYP/ 6-31 ＋ G＊＊ calculations. The calculation results predicted their stability and thermodynamic properties such as their values of Gibbs free energy, thermal enthalpies, thermal capacity and entropy. This research also shows that chemical calculations can be an important tool in scientific study. Accurate theoretical calculations can provide ways to obtain important chemical and physical information that cannot be easily obtained by experimental approaches. Clearly theoretical calculation gives a new method to investigate these systems.