Activation of Dioxygen Mediated by Metal Ions, and Synthetic Application.

金属离子介导的分子氧的活化及其合成应用。

基本信息

批准号：
61470081
负责人：
SASAKI Kazuo
金额：
$ 3.01万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-61470081/
关键词：
Activation of Dioxygen Hydroxyl Radical Copper(I) Ion Mediator One-Step Synthesis of Phenols ベンゼンの酸化金属イオンの効果

项目摘要

The main object of this work is placed on developing a synthetic method for one-step oxidation of benzene to phenols. In earlier works, we reported that Cu^+ ions can activate molecular xoygen. When benzene is present in the system, both phenol and hydroquinone are produced. The primary steps are estimated to be the reactions expressed by eqs. (1)-(3), but most of mechanistic details were left ambiguous.iCu^+ + O_2 + 2H^+ -> 2Cu^<2+> + H_2O_2 (1) ; Cu^+ + H_2O_2 + H^+ -> Cu^<2+> + OH + H_2O (2) ;OH + C_6H_6 -----> C_6H_5OH (3)In this work, mechanistic detail and synthetic feasibility of air oxidation of benzene catalyzed by Copper(1) ions were discussed. Conclusions are as follows.1. [Mechanism]. (1) By kinetic study, it is confirmed that active species is OH; (2) Deactivation occurs at the stage of OH or H_2O_2; (3) Efficiency for H_2O_2 production is quantitative; (4) The formation rate of H_2O_2 is much gaster than the decomposition rate.2. [Comparison with Other Systems]. ^<18>O-Tracer experiment indicates that hydroxy- cyclohexadienyl and its peroxy radicals are the intermediates. The formation of hydroquinone is characteristic feature of the present system, which is never observed in the other systems, such as the Fenton's reaction.3. [Synthetic Feasibility]. The relative ratio of phenol to hydroquinone strongly depends on solution pH. The former dominates at lower pHs (<3), and the latter at higher pHs (>3). When both continuous extraction and electrolytic regeneration of Cu^+ were applied to the system at pH 3, p-benzoquinone was obtained in a 50% current efficiency.The present system has several merits and, therefore, provides much synthetic feasibility. Namely, (1) Hydrogen peroxide is unnecessary; (2) The reaction is effective and mild; (3) Either phenol or hydroquinone is obtained selectively.

这项工作的主要对象是开发一种合成方法，将苯一步氧化为苯酚。在较早的作品中，我们报道了Cu^+离子可以激活分子xoygen。当系统中存在苯时，会产生苯酚和氢喹酮。估计主要步骤是等式表达的反应。（1） - （3），但大多数机械细节都含糊不清。ICU^ + + O_2 + 2H^ + - > 2cu^<2+> + H_2O_2（1）; Cu^ + + H_2O_2 + H^ + - > Cu^<2+> + OH + H_2O（2）; OH + C_6H_6 -----> C_6H_5OH（3）在这项工作中讨论了由铜（1）离子催化的苯。结论如下1。 [机制]。（1）通过动力学研究，可以证实活性物种是OH；（2）停用发生在OH或H_2O_2的阶段；（3）H_2O_2生产的效率是定量的；（4）H_2O_2的形成速率比分解速率宽大。2。 [与其他系统的比较]。 ^<18> O-Tracer实验表明羟基己二烯基及其过氧自由基是中间体。羟基酮的形成是当前系统的特征，在其他系统（例如Fenton的反应）中从未观察到。3。 [合成可行性]。苯酚与羟酮的相对比极大地取决于溶液pH。前者在较低的pHS（<3）中占主导地位，而后者则在较高的pHS（> 3）中占主导地位。当在pH 3时将Cu^+的连续提取和电解再生都应用于PH 3时，在50％的电流效率下获得了P-苯醌。当前系统具有多种优点，因此提供了很多合成的可行性。即（1）过氧化氢是不必要的；（2）反应有效且温和；（3）选择性地获得苯酚或氢喹酮。