KINETICS AND MECHANISM OF GENERAL-ACID-ASSISTED OXIDATION OF BROMIDE BY HYPOCHLORITE AND HYPOCHLOROUS ACID
KINETICS AND MECHANISM OF GENERAL-ACID-ASSISTED OXIDATION OF BROMIDE BY HYPOCHLORITE AND HYPOCHLOROUS ACID
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DOI：
10.1021/ic00263a030
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发表时间：
1987-08-12
影响因子：
4.6
通讯作者：
MARGERUM, DW
中科院分区：
文献类型：
--
作者：
KUMAR, K;MARGERUM, DW
溴化物被HOC1和OCT氧化的速率表达式为：d [OCT] T/di= fcHA [HA][OCl'] T [Br']，其中[OCT] T=[OCT]+[HOC1]，而HA是一般酸（H20, HP042 ', HC03 ', CH3COOH, ClCH2COOH，或H30+）。H30++ OCT+ Br’的kHA值为3.65 X 1010 M’2 s’1（该路径需要HOC1作为中间通道），而H30++ HOC1+ Br’的kHA值为1.32 X 106 M’2 s’1。在二阶表达式中，HOC1和Br' s的速率常数为1.55 X 103 M'1 ' s 1，而OCT+ Br' s的速率常数仅为0.90 X 10 ' 3 M'1 ' s 1。酸辅助反应（H304+ OCT除外）的机制是同时发生质子转移（从HA转移到OCT或HOC1）和Cl+转移到Br”（得到BrCl， BrCl迅速反应得到OBr”或Br2和Br3”）。HA与OCT和Br”反应的Bronsted a值为0.75，HA与hoc1和Br”反应的a值为0.27。a值反映了过渡态中质子转移的程度。
The rate expression for the oxidation of bromide by HOC1 and OCT is-d [OCT] T/di= fcHA [HA][OCl'] T [Br'], where [OCT] T=[OCT]+[HOC1] and HA is a general acid (H20, HP042", HC03", CH3COOH, ClCH2COOH, or H30+). The kHA value for H30++ OCT+ Br'is 3.65 X 1010 M'2 s'1 (this path requires HOC1 as an intermediate), while the kHA value for H30++ HOC1+ Br'is 1.32 X 106 M" 2 s'1. In terms of second-orderexpressions, the rate constant for HOC1 and Br'is 1.55 X 103 M'1 s" 1, while the rate constant for OCT+ Br'is only 0.90 X 10" 3 M" 1 s" 1. The proposed mechanism for the acid-assisted reactions (except for H304+ OCT) is a simultaneous proton transfer (from HA to OCT or to HOC1) and Cl+ transfer to Br"(to give BrCl, which reacts rapidly to give OBr" or Br2 and Br3"). The Bronsted a value is 0.75 for the reactions of HA with OCT and Br", and the a value is 0.27 for the reactions of HA withHOC1 and Br". The a values reflect the degree of proton transfer in the transition state.