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Correlation of 1H NMR chemical shift for associated systems by local composition model and two-liquid theory

XU Yingjie;WANG Congmin;LI Haoran;HAN Shijun   

  • Online:2006-09-25 Published:2006-09-25

用双液理论局部组成模型关联缔合体系核磁共振化学位移

许映杰;王从敏;李浩然;韩世钧   

  1. 浙江大学化学系,浙江 杭州 310027;绍兴文理学院化学化工学院,浙江 绍兴 312000

Abstract: The 1H NMR chemical shift is widely used to investigate the microstructure and thermodynamics of associated solution.Based on the concept of local composition and two-liquid theory, a semi-empirical physical local composition model was proposed to correlate 1H NMR chemical shift of associated solution.The model contained two parameters denoting the intermolecular interaction energy.The associated systems including self-associate and cross-associate mixtures were selected and investigated with the model.The results showed that the model could be used to correlate the 1H NMR chemical shift of various associated mixtures.Assuming that the model parameters do not change with temperature, then the chemical shift of the same binary system at a different temperature is predicted.Seven associated mixtures were tested as examples to study the influence of temperature on the mixture chemical shift, and the deviations of prediction were almost of the same order of magnitude with those of correlation.

摘要: 1H NMR化学位移被广泛用于研究缔合体系溶液微观结构和溶液热力学性质.本文基于局部组成思想和双液理论,提出了一个半经验的缔合体系核磁共振化学位移关联模型,模型中含有两个代表分子间相互作用力的待定参数.利用新提出的模型,对不同的缔合体系进行了关联,包括自缔、交叉缔等缔合体系.关联的结果表明,该模型能很好地描述各种不同缔合形式的缔合体系1H NMR化学位移随浓度的变化关系.同时利用模型参数中含有的温度关系,预测了同一体系在不同温度时的核磁共振化学位移,预测偏差和模型自身关联偏差基本在同一数量级上.