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研究了苯酚过氧化氢羟化过程中Dawson结构杂多化合物的ESR谱，通过对比不同反应时间后催化剂的波谱参数，分析了反应过程中V4+→V5+的变化情况．研究结果表明，在反应初期，催化剂仅存在少量V4+，在反应时间达到2h时V4+的含量迅速增多，并出现了V（Ⅰ）及V（Ⅱ）两种波谱参数相异的四价钒，其中V(Ⅰ)对应着V＝O键上的V4+，而V（Ⅱ）则对应着加氧中间物种，反应过程中V(Ⅱ)的含量迅速增多．两种钒均为羟化反应的活性中心
The ESR spectra of Dawson structure heteropoly compounds during the hydroxylation of phenol hydroperoxide were studied. The change of V4 + → V5 + during the reaction was analyzed by comparing the spectral parameters of the catalysts after different reaction time. The results showed that there was only a small amount of V4 + in the catalyst at the initial stage of the reaction, and the content of V4 + increased rapidly when the reaction time reached 2h. There were two tetravalent vanadium species, V (Ⅰ) and V (Ⅱ) V (Ⅰ) corresponds to V4 + on the V = O bond, while V (Ⅱ) corresponds to the oxygen-added intermediate species. The content of V (Ⅱ) rapidly increases during the reaction. Both vanadium are the active centers for hydroxylation