...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Oxidation of p-chlorotoluene and cyclohexene catalysed by polymer-anchored oxovanadium(IV) and copper(II) complexes of amino acid derived tridentate ligands
【24h】

Oxidation of p-chlorotoluene and cyclohexene catalysed by polymer-anchored oxovanadium(IV) and copper(II) complexes of amino acid derived tridentate ligands

机译：氨基酸衍生的三齿配体的聚合物固定的氧钒（IV）和铜（II）配合物催化对氯甲苯和环己烯的氧化

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

3-Formylsalicylic acid (Hfsal), covalently bound to chloromethylated polystyrene (PS) and cross-linked with 5% divinylbenzene reacts with D, L-alanine and L-isoleucine to give the Schiff-base tridentate ligands PS-H(2)fsal-D, L-Ala and PS-H2fsal-L-Ile, respectively. These anchored ligands upon reaction with VOSO4 and Cu(CH3COO)(2)center dot H2O form the complexes PS-[VO(fsal-D, L-Ala)(H2O)], PS-[Cu(fsal-D, L-Ala)(H2O)], PS-[VO(fsal-L-Ile)(H2O)] and PS-[Cu(fsal-L-Ile)(H2O)]. The structures of these immobilized complexes have been established on the basis of scanning electron micrographs, spectroscopic (infrared, electronic and EPR), thermogravimetric and elemental analysis studies. The oxidation of p-chlorotoluene and cyclohexene has been investigated using these complexes as the catalysts in the presence of H2O2 as the oxidant. Reaction conditions have been optimised by considering the concentration of the oxidant, the amount of catalyst used and the temperature of the reaction mixture. Under the optimised conditions, p-chlorotoluene gave a maximum of 14% conversion using PS-[VO(fsal-D, L-Ala)(H2O)] as the catalyst, with the main products having a selectivity order of: p-chlorobenzaldehyde p-chlorobenzylalcohol > p-chlorobenzoic acid > 2-methyl-5-chlorophenol > 3-methyl-6-chlorophenol. The oxidation of cyclohexene with PS-[VO(fsal-D, L-Ala)(H2O)] proceeds with 79% conversion, which is followed by PS-[VO(fsal-L-Ile)(H2O)] with 77% conversion, and the oxidation of cyclohexene by Cu-based catalysts occurs with considerably lower conversions (29-32%). The selectivity of the products follows the order: 2-cyclohexene-1-ol > cyclohexene oxide > cyclohexane-1,2-diol > 2-cyclohexene-1-one. Recycling studies indicate that these catalysts can be reused at least three times without any significant loss in their catalytic potential. However, EPR studies indicate that while the polymer supported V(IV)O-complexes do not change after being used, the EPR spectra of the Cu-complexes show significant changes. The corresponding non-polymer bound complexes [VO(fsal-D, L-Ala)(H2O)], [Cu(fsal-D, L-Ala)(H2O)], [VO(fsal-L-Ile)(H2O)] and [Cu(fsal-L-Ile)(H2O)] have also been prepared in order to compare their spectral properties and catalytic activities. The non-polymer bound complexes exhibit lower conversion, along with lower turn-over frequency as compared to their polymer-bound analogues. Several EPR, (VNMR)-V-51 and UV-vis studies have been undertaken to detect the intermediate species, and outlines for the mechanisms of the catalytic reactions are proposed.
机译：3-甲酰基水杨酸（Hfsal），共价结合到氯甲基化的聚苯乙烯（PS）上，并与5％二乙烯基苯交联，与D，L-丙氨酸和L-异亮氨酸反应，生成席夫碱三齿配体PS-H（2）fsal -D，L-Ala和PS-H2fsal-L-Ile。这些锚定的配体与VOSO4和Cu（CH3COO）（2）中心点H2O反应后形成PS- [VO（fsal-D，L-Ala）（H2O）]，PS- [Cu（fsal-D，L- Ala）（H 2 O）]，PS- [VO（fsal-L-Ile）（H 2 O）]和PS- [Cu（fsal-L-Ile）（H 2 O）]。这些固定化复合物的结构是在扫描电子显微镜，光谱学（红外，电子和EPR），热重和元素分析研究的基础上建立的。在H 2 O 2作为氧化剂的存在下，使用这些配合物作为催化剂，已经研究了对氯甲苯和环己烯的氧化。通过考虑氧化剂的浓度，所用催化剂的量和反应混合物的温度来优化反应条件。在最佳条件下，以PS- [VO（fsal-D，L-Ala）（H2O）]为催化剂，对氯甲苯的转化率最高为14％，主要产物的选择顺序为：对氯苯甲醛对氯苄醇>对氯苯甲酸> 2-甲基-5-氯苯酚> 3-甲基-6-氯苯酚用PS- [VO（fsal-D，L-Ala）（H2O）]氧化环己烯的转化率为79％，随后是PS- [VO（fsal-L-Ile）（H2O）]的转化率为77％铜基催化剂氧化环己烯的转化率非常低（29-32％）。产物的选择性遵循以下顺序：2-环己烯-1-醇>环己烯氧化物>环己烷-1,2-二醇> 2-环己烯-1-酮。循环研究表明，这些催化剂可以重复使用至少3次，而催化潜能没有任何重大损失。但是，EPR研究表明，尽管聚合物负载的V（IV）O-配合物在使用后没有改变，但Cu-配合物的EPR光谱显示出显着变化。相应的非聚合物结合复合物[VO（fsal-D，L-Ala）（H2O）]，[Cu（fsal-D，L-Ala）（H2O）]，[VO（fsal-L-Ile）（H2O） ）和[Cu（fsal-L-Ile）（H2O）]也已制备，以比较它们的光谱性质和催化活性。与非聚合物结合的类似物相比，非聚合物结合的复合物表现出较低的转化率和较低的翻转频率。已经进行了一些EPR，（VNMR）-V-51和UV-vis研究来检测中间物种，并提出了催化反应机理的概述。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号