ELECTRONIC-SPECTRA, PHOTOCHEMISTRY, AND AUTOXIDATION MECHANISM OF SULFITE-BISULFITE-PYROSULFITE SYSTEMS - SO2-, SO3-, SO4-, AND SO5- RADICALS
ELECTRONIC-SPECTRA, PHOTOCHEMISTRY, AND AUTOXIDATION MECHANISM OF SULFITE-BISULFITE-PYROSULFITE SYSTEMS - SO2-, SO3-, SO4-, AND SO5- RADICALS
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DOI：
10.1021/ja00756a009
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发表时间：
1972-01-01
影响因子：
15
通讯作者：
WILF, J
中科院分区：
文献类型：
--
作者：
HAYON, E;TREININ, A;WILF, J
研究了亚硫酸盐-亚硫酸氢盐-焦亚硫酸盐体系在溶液中的电子光谱和光化学性质。pH值，浓度和环境对电子光谱的影响进行了研究，并得出了一些系统的热力学性质和所涉及的电子跃迁的性质的信息。在190 nm以上，只有HS 03-显示出电荷转移到溶剂（CTTS）带，但在其分子内跃迁内激发时存在SO 312 - 34离子的有效电离。溶液中亚硫酸根离子的链式氧化可导致从系统中快速除去氧，从而允许观察到在这种“含空气”溶液中eaq-的强瞬态吸收。提出了自氧化机理：S 032-+ hv-+ SOr+ eaq-（+ 02-* 02-）; S 03-+ 02-* S 05-; S 05-+ S 032-->-S 04-+ S 042-; SOr+ S 032--* S 042-+ SOr，以及自由基的终止反应。有些物种可能以其酸性形式存在。该机理基于关于自由基SO 3-、SOr和SOr的结果。这些自由基的信息是从闪光光解的SO 32-和S20 62-，和从脉冲辐解的SO 32-，S20 s 2-，和HSOr。没有直接证据表明SOr自由基在链反应中的作用，但它是从醇诱导的抑制性质（SOr和SO 6-对醇相对惰性）和从碱性溶液中Or的产生推断的。S2062-的光解导致SOr自由基的形成。S_2O_3 ~（2-）的闪光光解提供了有关该自由基的新信息。本文综述了硫的含氧阴离子和氧自由基的一些性质。包括自由基SOr、SOr、SO 4-和SOf的吸收最大值、消光系数、衰减动力学和反应性。
The electronic spectrum and the photochemistry of the sulfite-bisulfite-pyrosulfite systems in solution were investigated. The effects of pH, concentration, and environment upon the electronic spectrum were studied, and information was derived on some thermodynamic properties of the system and on the nature of the electronic transitions involved. Above 190 nm only HS03~ displays a charge-transfer-to-solvent (CTTS) band, but there is efficient ionization of the S031 2-34ion on excitation within its intramolecular transition. The chain oxidation of sulfite ions in solution can lead to fast removal of oxygen from the system thus permitting the observation of the strong transient absorption of eaq-in such “air-containing” solutions. A mechanism for the autoxidation is pro-posed: S032-+ hv-+ SOr+ eaq-(+ 02-* 02~); S03~+ 02-* S05-; S05-+ S032-->-S04-+ S042-; SOr+ S032--* S042-+ SOr, and termination reactions of the radicals. Some of the species may be present in their acidic forms. This mechanism is based on results concerning the radicals S03~, SOr, and SOr. Information on these radicals was obtained from the flash photolysis of S032-and S20 62-, and from the pulse radiolysis of S032-, S2Os2-, and HSOr. No direct evidence is presented for the role of SOr radicals in the chain reaction, but it is inferred from the nature of the inhibition induced by alcohols (SOr and S06~ are relatively inert to alcohols) and from the production of Or in alkaline solutions. The photolysis of S2062-leads to the formation of SOr radicals. The flash photolysis of S2Os2-has provided new information on this radical. A survey is presented onsome of the properties of the oxyanions and oxyradicals of sulfur. The absorption maxima, extinction coefficients, decay kinetics, and reactivity of the radicals SOr, SOr, S04-, and SOf are included.