The electro-oxidation of water and alcohols at BDD in hexafluoroisopropanol
The electro-oxidation of water and alcohols at BDD in hexafluoroisopropanol
复制标题
DOI：
10.1016/j.jelechem.2013.03.024
复制
发表时间：
2013-07-15
影响因子：
4.5
通讯作者：
Baltruschat, Helmut
中科院分区：
文献类型：
--
作者：
Ayata, Sevda;Stefanova, Ana;Baltruschat, Helmut
掺硼金刚石电极具有较宽的电位窗口，因此可以形成自由基并研究它们的反应。六氟异丙醇能够大大延长自由基阳离子的寿命。在这里，我们研究了BDD电极上一系列含羟基物质在该溶剂中的氧化：水和最简单的伯醇、仲醇和叔醇，即甲醇、异丙醇和叔丁醇。其氧化的难易程度并不取决于氢的碱性，而是取决于键的离解能。由水、甲醇和异丙醇形成的自由基寿命非常短，我们只能电化学检测第二反应产物，即氢离子。相比之下，叔丁醇被氧化为中间体，其在几秒钟内转化为另一种物质要慢得多。该物质可以比第一中间体或初始反应物更容易地被进一步氧化。有一些证据表明，反应物分子起着双重作用：一方面，它们进行氧化氢提取。另一方面，它们稳定产生的氢离子。(C)2013爱思唯尔有限公司版权所有。
Boron doped (BDD) diamond electrodes have a wide potential window and thus allow the formation of radicals and the investigation of their reactions. Hexafluoroisopropanol is able to extend greatly the lifetime of radical cations. Here, we investigated the oxidation of a series of the hydroxyl containing species at a BDD electrode in that solvent: water and the simplest primary, secondary, and tertiary alcohols, i.e. methanol, i-propanol, and t-butanol. The ease of their oxidation does not follow the hydrogen basicity but rather the bond dissociation energy. The radicals formed from water, methanol, and i-propanol are very short-lived and we can detect electrochemically only the second reaction product, i.e. the hydrogen ions. In contrast, t-butanol is oxidised to an intermediate, which is transformed much more slowly within some seconds to another species. This species can be further oxidised more easily than the first intermediate or the initial reactant. There is some evidence, that the reactant molecules play a dual role: on the one hand they undergo oxidative hydrogen abstraction. On the other hand, they stabilise the produced hydrogen ions. (C) 2013 Elsevier B.V. All rights reserved.