Ca^(2+)在邻苯二酚氧化过程中的作用机制  

Effect and Mechanism of Ca^(2+) in the Oxidation Process of Catechol Substances

作　　者：陈义鑫 尹俊钧 罗炜艳 王夺 CHEN Yi-xin;YIN Jun-jun;LUO Wei-yan;WANG Duo(College of Energy,Xiamen University,Xiamen 361102,China)

机构地区：[1]厦门大学能源学院,福建厦门361102

出　　处：《化学试剂》2021年第12期1735-1742,共8页Chemical Reagents

基　　金：国家自然科学基金资助项目(21978247)。

摘　　要：以邻苯二酚为对象,通过抗氧化活性测试间接定量分析了Ca^(2+)对邻苯二酚自氧化程度的影响。结果表明,随着在不同Ca^(2+)浓度、反应时间、反应温度下,邻苯二酚的DPPH自由基清除能力分别下降了12.96%、26.32%和12.50%,说明邻苯二酚的自氧化程度均有所提高。选择了两种具有邻位羟基结构的酚类化合物,通过紫外-可见吸收光谱(UV-Vis)发现邻苯二酚、儿茶素和去甲肾上腺素的氧化程度均明显提高。此外,邻苯二酚与Ca^(2+)之间发生了配位反应,在溶液中生成了不溶性的配合物。通过TGA、ICP-OES、元素分析等表征手段,发现邻苯二酚是以2∶1的物质的量比与Ca^(2+)进行配位。进一步对产物分析,证明了邻苯二酚与Ca^(2+)是以两个酚羟基中的氧原子与Ca^(2+)结合,螯合形成了邻苯二酚钙配合物,进而提出了Ca^(2+)介导邻苯二酚氧化的路径。The DPPH radical scavenging ability of Ca^(2+) on catechol under different conditions was studied,and the effect of Ca^(2+) on the degree of autoxidation of catechol was indirectly quantified by the antioxidant activity test method.The results showed that the DPPH radical scavenging ability of catechol decreased by 12.96%,26.32% and 12.50% with the increases of the Ca^(2+) concentration from 0 to 2 mol/L,the reaction time from 0 to 120 min,and the reaction temperature from 4 to 90 ℃,respectively,indicating that the degree of autoxidation of catechol was increased in all cases.Two phenolic compounds with an adjacent hydroxyl structure were selected and their oxidation levels in the presence or absence of Ca^(2+) were directly and qualitatively compared by UV-Vis analysis.The results showed that the degree of oxidation was significantly higher for catechol,catechin and norepinephrine.In addition,the coordination between catechol and the calcium ions occurs,generating insoluble substances in the solution.After analysis with TGA,ICP-OES and elemental analysis,it was found that the coordination between catechol and the calcium ion in molar ratio of 2 ∶1.The characterization of the coordinated complex demonstrated that catechol as a bidentate ligand coordinates through the oxygen atom of its phenolic groups,forming a stable chelating structure.Finally,a pathway for calcium ion-mediated oxidation of catechol was proposed for the application of phenolic compounds.

关 键 词：邻苯二酚 抗氧化 钙离子 配合 配位反应 

分 类 号：TQ35[化学工程]