KINETICS OF THE REACTIONS OF THE SO4- RADICAL WITH SO4-, S2O82-, H2O AND FE2+
KINETICS OF THE REACTIONS OF THE SO4- RADICAL WITH SO4-, S2O82-, H2O AND FE2+
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DOI：
10.1039/ft9908602557
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发表时间：
1990-07-21
期刊：
影响因子：
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通讯作者：
WAYGOOD, SJ
中科院分区：
文献类型：
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作者：
MCELROY, WJ;WAYGOOD, SJ
硫酸根阴离子 SO4- 是自由基引发的 SO2 水相有氧氧化过程中的关键中间体。 K2S2O8 溶液光解后在 248 nm 处获得 SO4- 的吸收光谱。动力学分光光度技术已被用来研究 SO4- 在 S2O82- 和 Fe11 存在下的衰变。在 293 K 下确定了几个速率常数：2k(SO4- + SO4-) = (8.9.+-.0.3)×。 108 dm3 mol-1 s-1（无限稀释），k(SO4- + S2O82-) = (6.1 .+-. 0.6) × 105 dm3 mol-1 s-1（无限稀释）和 k(SO4- + H2O) = (500 .+-. 60) s-1。 SO4- 与 Fe11 的反应通过快速平衡步骤进行，然后是决定速率的电子转移。 k1、k-1和k2在293K时的值为(3.0±1.9)×。 108 dm3 mol-1 s-1 (4.8.+-.3.0)× 104 s-1 (6.5.+-.2.1) 次。分别为103 s-1。讨论了这些结果对当前云和降水化学模型的影响。
The sulphate radical anion, SO4-, is known to be a key intermediate in the aqueous aerobic oxidation of SO2 initiate by free radicals. The absorption spectrum of SO4- has been obtained following photolysis of K2S2O8 soltuions at 248 nm. Kinetic spectrophotometric techniques have been employed to investigate the decay of SO4- in the presence of S2O82- and Fe11. Several rate constants have been determined at 293 K: 2k(SO4- + SO4-) = (8.9 .+-. 0.3) .times. 108 dm3 mol-1 s-1 (at infinite dilution), k(SO4- + S2O82-) = (6.1 .+-. 0.6) .times. 105 dm3 mol-1 s-1 (at infinite dilution) and k(SO4- + H2O) = (500 .+-. 60) s-1. The reaction of SO4- with Fe11 proceeds via a rapid equilibration step followed by electron transfer which is rate-determining. Values of k1, k-1 and k2 at 293 K are (3.0 .+-. 1.9) .times. 108 dm3 mol-1 s-1 (4.8 .+-. 3.0) .times. 104 s-1 (6.5 .+-. 2.1) .times. 103 s-1 respectively. The implications of these results for current cloud and precipitation chemistry models are discussed.