Intramolecular hydrogen migration in alkylperoxy and hydroperoxyalkylperoxy radicals: accurate treatment of hindered rotors.
Intramolecular hydrogen migration in alkylperoxy and hydroperoxyalkylperoxy radicals: accurate treatment of hindered rotors.
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DOI：
10.1021/jp9098792
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发表时间：
2010-04
期刊：
影响因子：
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通讯作者：
Sandeep Sharma;S. Raman;W. Green
中科院分区：
文献类型：
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作者：
Sandeep Sharma;S. Raman;W. Green
我们用CBS-QB 3和B3 LYP/CBSB 7方法计算了标题反应族中稳定分子和反应的热化学和速率系数。对于具有多个内部转子的分子的受阻转子的精确处理可能是有问题的，所述内部转子具有彼此不独立的电势，并且提出了一种简化的方案来处理它们。这对于氢过氧烷基过氧自由基（HOOQOO）特别重要。本文提出了两个新的热化学基团值，用这些基团值，在反应机理发生器（RMG）中实现的计算焓的基团加和法与CBS-QB 3的预测结果吻合得很好。势垒高度遵循埃文斯-波兰尼关系的每一种类型的分子内氢迁移反应的研究。
We have calculated the thermochemistry and rate coefficients for stable molecules and reactions in the title reaction families using CBS-QB3 and B3LYP/CBSB7 methods. The accurate treatment of hindered rotors for molecules having multiple internal rotors with potentials that are not independent of each other can be problematic, and a simplified scheme is suggested to treat them. This is particularly important for hydroperoxyalkylperoxy radicals (HOOQOO). Two new thermochemical group values are suggested in this paper, and with these values, the group additivity method for calculation of enthalpy as implemented in reaction mechanism generator (RMG) gives good agreement with CBS-QB3 predictions. The barrier heights follow the Evans-Polanyi relationship for each type of intramolecular hydrogen migration reaction studied.