Theoretical Study on Gas—phase Pyrolytic Reactions of N—Ethyl,Isopropyl and N—t—Butyl Substituted 2—Aminopyrazine |
| |
摘 要: |
|
关 键 词: | 过度态 气相热解反应 2-氨基吡嗪 理论研究 量子化学 密度泛函 |
Theoretical Study on Gas‐phase Pyrolytic Reactions of N‐Ethyl,N‐Isopropyl and N‐t‐Butyl Substituted 2‐Aminopyrazine |
| |
Authors: | Chen Li‐Ping Hong San‐Guo |
| |
Abstract: | Density functional theory (DFT) and ab initio methods were used to study gas‐phase pyrolytic reaction mechanisms of iV‐ethyl, N‐isopropyl and N‐t‐butyl substituted 2‐aminopyrazine at B3LYP/6–31G* and MP2/6–31G*, respectively. Single‐point energies of all optimized molecular geometries were calculated at B3LYP/6–311 + G(2d,p) level. Results show that the pyrolytic reactions were carried out through a unimolecular first‐order mechanism which were caused by the migration of atom H(17) via a six‐member ring transition state. The activation energies which were verified by vibrational analysis and correlated with zero‐point energies along the reaction channel at B3LYP/6–311 + G(2d,p) level were 252.02 kJ. mo?1 (N‐ethyl substituted), 235.92 kJ‐mol?1 (N‐t‐isopropyl substituted) and 234.27 kJ‐mol?1 (N‐t‐butyl substituted), respectively. The results were in good agreement with available experimental data. |
| |
Keywords: | 2‐aminopyrazine pyrolytic reaction density functional theory ab initio transition state |
|