Electrocatalytic reduction of ethylene dibromide by Vitamin B12 in a surfactant-stabilized emulsion.
Electrocatalytic reduction of ethylene dibromide by Vitamin B12 in a surfactant-stabilized emulsion.
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表面活性剂稳定乳液中维生素 B12 电催化还原二溴乙烷。
DOI：
10.1021/ac00144a025
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发表时间：
1987
影响因子：
7.4
通讯作者：
Owlia,A
中科院分区：
文献类型：
--
作者：
Rusling,JF;Connors,TF;Owlia,A
在以Aero-sokOT（AOT）和四乙基高氯酸铵（TEAP）为稳定剂的异辛烷/水乳状液体系中，采用含维生素B12的电催化循环，在玻碳电极上还原烷基邻位二溴。在均相介质中，催化还原比直接还原降低过电位约0.8V.该催化剂的关键Co（II）/Co（I）还原步骤的非均相速率常数（0.0056cm·s ~（-1））比在pH 2.3的乙腈水溶液中的非均相速率常数小约3倍。1，2-二溴乙烷和1，2-二溴丁烷与Co（I）的限速化学反应的表观速率常数在104 L mol-1 s-1的数量级上显著小于在乙腈水溶液中，因为底物分配到烃相中。尽管有这些动力学限制，方波伏安法可用于催化循环，以估计无铅和含铅汽油中的总乙烯二卤化物在用汽油制备的AOT/TEAP乳液中，二溴化乙烯（EDB），或1，2-二溴乙烷，是一种可疑的人类致癌物（1），已被用作农业杀虫剂和含铅汽油中铅的清除剂（2）。这些和其他来源造成了严重污染的地下水在美国东北部（1，3，4）。储存罐的交叉污染导致无铅汽油中含有微量的EDB。邻位二溴化物可在汞电极上直接还原，生成烯烃和溴离子（5-8）。最近提出用直流或脉冲极谱法直接还原EDB（8）。虽然获得了良好的精密度和准确度，但直接还原所需电位约为-1.6Vvs.SCE。在电极上如此高的还原能力下，某些真实的样品基体中的其它物种可能在接近-1.6V的电位下被还原，干扰EDB的测定。阿索，使用汞作为电极可以复杂的电极过程与烷基卤化物或还原中间体（7，9）的化学反应。
Alkyl vicinal dibromides were reduced at glassy carbon electrodes In Isooctane/water emulsions stabilized by Aero-sokOT (AOT) and tetraethylammonium perchlorate (TEAP) by using an electrocatalytic cycle Involving vitamin B12. Catalysis lowers the overpotential by about 0.8 V compared todirect reduction In a homogeneous medium. The heterogeneous rate constant (0.0056 cm s-1) for the key Co (II)/Co (I) re-duction step of the catalyst was about 3-fold smaller than In pH 2.3 aqueous acetonitrile. Apparent rate constants on the order of 104 L mol" 1 s" 1 for the rate-limiting chemical reactions of 1, 2-dibromoethane and 1, 2-dibromobutane with Co (I) were considerably smaller than In aqueous acetonitrile because of the partitioning of substrate Into the hydrocarbon phase. Despite these kinetic limitations, square-wave voltammetry could be used with the catalytic cycle to estimate total ethylene dlhalldes In unleaded and leaded gasoline In AOT/TEAP emulsions prepared with gasoline.Ethylene dibromide (EDB), or 1, 2-dibromoethane, is a suspected human carcinogen (1) which has been used as an agricultural biocideand as a scavenger of lead in leaded gasoline (2). These and other sources have caused serious contamination of groundwaters in the northeastern United States (1, 3, 4). Cross-contamination of storage tanks has led to trace quantities of EDB in unleaded gasoline. Vicinal dibromides can be reduced directly at mercury electrodes to yield alkenes and bromide ions (5-8). Direct reduction by dc or pulse polarography was recently proposed as a method of determining EDB (8). Although good precision and accuracy were obtained, direct reduction required po-tentials of about-1.6 V vs. SCE. With such a high reducing power at the electrode, other species in some real sample matrices might be reducedat potentials close to-1.6 V and interfere in the determination of EDB. Aso, use of mercury as an electrode can complicate the electrode process by chemical reaction with alkyl halides or reduction intermediates (7, 9).
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异生素的代谢激活：二溴乙烯和结构类似物
影响因子：
2.2
作者：
P. J. Bladeren
通讯作者：
P. J. Bladeren
全氟三丁胺乳液中氧的电化学和动力学研究
影响因子：
6.2
作者：
A. Berthold;J. Georges
通讯作者：
J. Georges
表面活性剂对水中和苯中维生素 B(12A) 配体交换反应的影响、水胶束的影响和溶剂限制
DOI：
10.1002/chin.197452104
发表时间：
1974
期刊：
ChemInform
影响因子：
--
作者：
J. Fendler;F. Nome;H. V. Woert
通讯作者：
H. V. Woert
影响因子：
3.6
作者：
J. Casanova;H. R. Rogers
通讯作者：
H. R. Rogers
球形电极扩展空间网格数字模拟电化学数据的回归分析。
影响因子：
7.4
作者：
Arena,JV;Rusling,JF
通讯作者：
Rusling,JF