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首页> 外文期刊>Chemistry: A European journal >Catalytic Hydroxylation of Benzene to Phenol by Dioxygen with an NADH Analogue
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Catalytic Hydroxylation of Benzene to Phenol by Dioxygen with an NADH Analogue

机译：NADH类似物通过双氧将苯催化羟基化为苯酚

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摘要

Hydroxylation of benzene by molecular oxygen (O-2) occurs efficiently with 10-methyl-9,10-dihydroacridine (AcrH(2)) as an NADH analogue in the presence of a catalytic amount of Fe(ClO4)(3) or Fe(ClO4)(2) with excess trifluoroacetic acid in a solvent mixture of benzene and acetonitrile (1: 1 v/v) to produce phenol, 10-methylacridinium ion and hydrogen peroxide (H2O2) at 298 K. The catalytic oxidation of benzene by O-2 with AcrH(2) in the presence of a catalytic amount of Fe(ClO4)(3) is started by the formation of H2O2 from AcrH(2), O-2, and H+. Hydroperoxyl radical (HO2 center dot) is produced from H2O2 with the redox pair of Fe3+/Fe2+ by a Fenton type reaction. The rate-determining step in the initiation is the proton-coupled electron transfer from Fe2+ to H2O2 to produce HOC and H2O. HOC abstracts hydrogen rapidly from H2O2 to produce HO2 center dot and H2O. The Fe3+ produced was reduced back to Fe2+ by H2O2. HO2 center dot reacts with benzene to produce the radical adduct, which abstracts hydrogen from AcrH(2) to give the corresponding hydroperoxide, accompanied by generation of acridinyl radical (AcrH(center dot)) to constitute the radical chain reaction. Hydroperoxyl radical (HO2 center dot), which was detected by using the spin trap method with EPR analysis, acts as a chain carrier for the two radical chain pathways: one is the benzene hydroxylation with O-2 and the second is oxidation of an NADH analogue with O-2 to produce H2O2.
机译：在催化量的Fe（ClO4）（3）或Fe存在下，用10-甲基-9,10-二氢ac啶（AcrH（2））作为NADH类似物有效地发生分子氧（O-2）对苯的羟基化反应（ClO4）（2）与过量的三氟乙酸在苯和乙腈的溶剂混合物中（1：1体积比）在298 K下生产苯酚，10-甲基ac离子和过氧化氢（H2O2）。苯的催化氧化通过AcrH（2），O-2和H +形成H2O2，在催化量的Fe（ClO4）（3）存在下，用AcrH（2）形成O-2。氢过氧自由基（HO2中心点）是通过Fenton型反应由H2O2与Fe3 + / Fe2 +的氧化还原对生成的。引发过程中的决定速率的步骤是将质子偶联的电子从Fe2 +转移到H2O2以生成HOC和H2O。 HOC从H2O2中迅速提取氢，生成HO2中心点和H2O。产生的Fe3 +被H2O2还原成Fe2 +。 HO2中心点与苯反应生成自由基加合物，该自由基加合物从AcrH（2）提取氢以生成相应的氢过氧化物，并伴有a啶基自由基（AcrH（中心点））的生成，从而构成自由基链反应。氢过氧自由基（HO2中心点）是通过自旋阱方法和EPR分析检测的，它充当两个自由基链途径的链载体：一个是苯被O-2羟基化，第二个是NADH的氧化与O-2相似，生成H2O2。

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