4,6-二硝基苯并氧化呋咱(DNBF)合成反应及动力学的理论研究

摘要

The geometries of all stationary points (reactants,products,and the transition state) involved in the reaction mechanism of preparing the 4,6-dinitrobenzofuroxan(DNBF) from 1-azido-2,4,6-trinitrobenze (TNAB) by the “furoxan mechanism” with a nitrogen molecule elimination are optimized by B3LYP theory with the cc-pVTZ basis sets and their vibretion frequencies are analyzed.The minimum-energy paths are obtained by the intrinsic reaction coordinate (IRC) theory.The rate constants are calculated over a wide temperature region from 200 to 2500 K by TST,TST/Eckart and RRKM(T)/Eckart methods by the Vklab program,respectively.The calculated results show that the tunneling effect is very important to the reaction at low temperatures.%采用B3LYP方法,在cc-pVTZ基组水平下,对2,4,6-三硝基叠氮苯(TNAB)脱去一分子氮气合成4,6-二硝基苯并氧化呋咱(DNBF)的反应历程中,所涉及的各驻点(包括反应物、产物及过渡态)进行几何结构优化和振动频率分析,采用内禀反应坐标理论(IRC)获得反应的最小能量路径(MEP).最后,通过VKLab程序包,采用TST、TST/Eckart和RRKM(T)/Eckart理论,计算了反应在200～2500K的速率常数.计算结果表明,在低温时,反应的隧道效应较为显著.