儿茶酚气相热解生成的自由基。2. 儿茶酚和对苯二酚热解的比较。

Radicals from the gas-phase pyrolysis of catechol. 2. Comparison of the pyrolysis of catechol and hydroquinone.

机构信息

Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA.

出版信息

J Phys Chem A. 2010 Sep 23;114(37):10110-6. doi: 10.1021/jp1054588.

PMID:20731470

Abstract

Formation of radicals from the pyrolysis of catechol (CT) and hydroquinone (HQ) over a temperature range of 350-900 °C was studied using low-temperature matrix isolation electron paramagnetic resonance (LTMI EPR) spectroscopy. Comparative analysis of the pyrolysis mechanisms of these isomeric compounds was performed, and the role of semiquinone-type carrier radicals was studied. Pathways of unimolecular decomposition of intermediate radicals and molecular products were identified from the examination of the potential energy surface of catechol calculated at B3LYP hybrid density functional theory and composite CBS-QB3 levels. The results were compared with the experimental observations and mechanistic pathways previously developed for the pyrolysis of hydroquinone.

摘要

采用低温基质隔离电子顺磁共振（LTMI EPR）光谱法研究了邻苯二酚（CT）和对苯二酚（HQ）在 350-900°C 温度范围内的热解自由基的形成。对这些异构体化合物的热解机制进行了比较分析，并研究了半醌型载体自由基的作用。通过在 B3LYP 混合密度泛函理论和复合 CBS-QB3 水平上计算邻苯二酚的势能面，鉴定了中间自由基和分子产物的单分子分解途径。将结果与先前为对苯二酚热解开发的实验观察和机理途径进行了比较。