Hydroxyl-containing compounds (water, methanol, and phenol) act as efficient catalysts of the chain reactions of thiophenol with quinone imines at their propagation steps as it was found previously for thiols. The results of quantum chemical analysis of isomerization of a radical adduct into phenoxyl radical or corresponding aromatic aminyl radical are considered. The adduct was formed at the rate limiting step of the chain propagation by thiyl radical addition to quinone imine. Enthalpies and activation energies for mono- and bimolecular isomerization of the adduct with participation of hydroxyl-containing compounds were computed and matched. For comparison, analogous reactions with participation of thiols (hydrogen sulfide, metahnthiol and thiophenol) were also studied. In both the cases, the catalytic effect is caused by transforming the four-membered cyclic transition state of the monomolecular isomerization reaction into the energetically favorable six-membered transition state by the O—H or S—H groups of the indicated compounds. This considerably reduces the activation energy.

中文翻译：

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含羟基化合物在苯硫酚与醌亚胺链式反应增长阶段的催化作用

含羟基的化合物（水、甲醇和苯酚）可作为苯硫酚与醌亚胺在其传播步骤中链式反应的有效催化剂，正如之前发现的硫醇一样。考虑了自由基加合物异构化为苯氧基自由基或相应的芳族氨基自由基的量子化学分析结果。加合物是在链增长的限速步骤通过硫基自由基加成到醌亚胺形成的。计算并匹配了含羟基化合物参与的加合物单分子和双分子异构化的焓和活化能。为了比较，还研究了硫醇（硫化氢、甲硫醇和苯硫酚）参与的类似反应。在这两种情况下，催化作用是通过指定化合物的 OH 或 SH 基团将单分子异构化反应的四元环过渡态转化为能量有利的六元过渡态引起的。这大大降低了活化能。