一种酚醛树脂模型化合物热解反应的密度泛函理论研究及实验验证

邻-邻位亚甲基桥是酚醛树脂主体结构单元之间的主要链接方式之一。采用Gaussian 09中的密度泛函理论B3LYP/6-311G(d,p)方法,对邻-邻位亚甲基桥型模型化合物邻位双羟苯基甲烷(2BHM)的热解反应机理进行了量子化学理论研究。设计了5种热解反应途径,对每种反应途径的反应物、产物和过渡态的结构进行了能量梯度全优化,并对过渡态进行了IRC验证。计算了各反应途径的标准动力学参数,最后进行了相关实验验证。计算结果表明Path3为2BHM的最优热解路径,对应的产物为苯酚和邻甲酚,所有路径的终产物中均有苯酚,且CO_2要比CO更容易生成。热解实验结果显示热解产物中苯酚含量最高,而CO并未出现。这说明计算结果与实验结果基本一致,同时也表明应用量子化学计算理论研究酚醛树脂的热解机理是一种有效的研究方法。

Pyrolysis Reactions of One Model Compound of Phenolic Resin Using Density Functional Theory and Experimental Validation

O-o'' methylene bridge is one of primary linkage among phenol-formaldehyde resins structure units. Pyrolysis mechanism of the 2BHM as a model compound was investigated by using density functional theory B3LYP methods at 6-311G(d,p) level in Gaussian 09 package. Six kinds of paths of pyrolysis reactions were designed, and the equilibrium geometries of the reactants, transition states and products of every reaction path were optimized, and the transition states were checked using IRC method. The standard kinetics parameters of every path were calculated. The calculation results show that Path3 are the major reaction channels and the corresponding products are phenol and o-cresol. Product of all path include phenol, and the CO₂ generates more easily than CO. Pyrolysis experiment results show that phenol content is the highest, and no CO is formed. This shows that the calculation results are basically identical to the experimental results, at the same time also shows that the application of quantum chemistry calculation theory to study the pyrolysis mechanism of phenolic resin is a kind of effective research method.