...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Complexation of Phenols and Thiophenol by Phosphine Oxides and Phosphates. Extraction, Isothermal Titration Calorimetry, and ab Initio Calculations
【24h】

Complexation of Phenols and Thiophenol by Phosphine Oxides and Phosphates. Extraction, Isothermal Titration Calorimetry, and ab Initio Calculations

机译：

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

To develop a new solvent-impregnated resin system for the removal of phenols from water the complex formation of triisobutylphosphine sulfide (TDBPS), tributylphosphate (TBP), and tri-n-octylphosphine oxide (TOPO) with a series of phenols (phenol, thiophenol, 3-chlorophenol, 3,5-dichlorophenol, 4-cyanophenol, and pentachlorophenol) was studied. The investigation of complex formation between the extractants and the phenols in the solvent toluene was carried out using liquid—liquid extraction, isothermal titration calorimetry (1TC), and quantum chemical modeling (B3LYP/6-311+G(d,p)//B3LYP/6-311G(d,p) and MP2/6-311++G(2d,2p)// B3LYP/6-31 1G(d,p)). The equilibrium constant (binding affinity, K_(chem)), enthalpy of complex formation (ΔH), and stoichiometry (N) were directly measured with ITC, and the entropy of complexation (ΔS) was derived from these results. A first screening of K_(chem) toward phenol revealed a very high binding affinity for TOPO, and very low binding affinities for the other extractants. Modeling results showed that although 1:1 complexes were formed, the TIBPS and TBP do not form strong hydrogen bonds. Therefore, in the remainder of the research only TOPO was considered. K_(chem) of TOPO for the phenols in toluene increased from 1 000 to 10 000 M~(-1) in the order phenol < pentachlorophenol < 3-chlorophenol < 4-cyanophenol ≈ 3,5-dichlorophenol (in line with their pK_a values, except for pentachlorophenol) in the absence of water, while the stoichiometric ratio remained 1:1. In water-saturated toluene, the binding affinities are lower due to co-complexation of water with the active site of the extractant. The increase in binding affinity for TOPO in the phenol series was confirmed by a detailed ab initio study, in which ΔH was calculated to range from —10.7 kcal/mol for phenol to -13.4 kcal/mol for 4-cyanophenol. Pentachlorophenol was found to behave quite differently, showing a ΔH value of —10.5 kcal/mol. In addition, these calculations confirm the formation of 1:1 H-bonded complexes.

著录项

相似文献

  • 外文文献
  • 中文文献
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