乙醇自由基代谢机理的理论研究*1

目的：从原子尺度对乙醇与自由基的反应进行探索，提高对乙醇自由基代谢机理的微观认识。方法在 CCSD（T）／6-311G（2d，2p）／／B3LYP／6-31G（d，p）计算水平下，采用量子化学方法详细研究了 C2 H5 OH 与·OH、H2 O2和·O2 H 的反应。结果（1）乙醇与·OH 和·O2 H 自由基的反应都存在3类反应（氢抽提、C—C 键断裂和 SN 2取代）。（2）在乙醇与 H2 O2的反应中，以 H 2 O2形成的水合氧自由基（·OOH2）直接插入乙醇的 C—H 键生成乙二醇为主，此外 H2 O2也可均裂为2个·OH 和异裂为· H＋·O2 H 自由基。结论乙醇与自由基（·OH、·O2 H）和 H2 O2反应中，分别以α氢抽提过程和· OOH2插入乙醇的α-C—H 键生成乙二醇为主要反应。

Theoretical research into the mechanism of free radical metabolism for ethanol

Objective—To improve the microcosmic cognition of the mechanism of free radical me-tabolism for ethanol by making investigations into the reaction between ethanol and radicals on atomic scale.Methods—With the CCSD(T)/6-311G(2d,2p)//B3LYP/6-31G(d,p)level of theory,the re-actions between ethanol and radicals like H2 O2 ,·OH and ·O2 H have been explored in details.Re-sults—(1)There are three reaction channels between ethanol and ·OH or ·O2 H (hydrogen abstrac-tion,C—C bond cleavage and SN 2 substitution).(2)Between H2 O2 and ethanol,H 2 O2 can form the hydrated oxygen radicals (·OOH2 ),which can directly insert into the C—H bond of ethanol.Moreo-ver,the H2 O2 molecule produces two ·OH radicals by homolysis or ·H + ·O2 H radicals by heterol-ysis.Conclusion—Theα-H abstraction reaction is the main channel between ethanol and ·OH or ·O2 H,while,the production of ethylene glycol through the formation of ·OOH 2 and its insertion intoα-C—H bond of ethanol is the main path for the reaction of ethanol with H2 O2 .