金属离子和CTAB胶束催化H_2O_2氧化对苯二酚的研究

Oxidation of p-Benzoquinone with Hydrogen Peroxide Catalyzed by Metal ions and CTAB Micelle

作者定性地研究了25℃,中性(pH6.8)水溶液中金属离子(Cu2+、Fe2+、Fe3+、Co2+和Mn2+)催化H2O2氧化对苯二酚,结果表明Fe2+和Fe3+对对苯二酚的氧化有较好的催化效果,Cu2+有一定的催化能力,而Mn2+和Co2+基本没有催化活性,这主要取决于金属离子与H2O2结合能否产生活性自由基·OH.同时,还定量地研究了CTAB胶束催化H2O2氧化对苯二酚.根据"假相模型"获得了CTAB胶束相中对苯二酚氧化反应的速率常数km以及对苯二酚与CTAB胶束的结合常数KS,这表现出了典型的胶束催化特征.

The oxidation of p-benzoquinone with hydrogen peroxide catalyzed by metal ions (Cu^(2+)、Fe^(2+)、Fe^(3+)、Co^(2+)、Mn^(2+)) has been investigated qualitatively in aqueous solution of pH 6.8 at 25 ℃ in this paper. The results suggested that Fe^(2+) and Fe^(3+) had good catalytic effects on the oxidation of p-benzoquinone with hydrogen peroxide, and Cu^(2+) had certain catalytic effect, however, Mn^(2+) and Co^(2+) had little catalytic effect. This is caused mainly by the formation of free group ·OH through the association of metal ion and H_2O_2. Meanwhile, the oxidation of p-benzoquinone with hydrogen peroxide catalyzed by CTAB micelle has also been studied quantitatively. According to the 'pesudophase model', the rate constant k_m and the association constant K_S for the oxidation of p-benzoquinone in CTAB micelle have been obtained, indicating the typical properties of micellar catalysis. The effects of metal ions and CTAB micelle on the oxidation of p-benzopuinone with hydrogen peroxide have been discussed in detail.