【作者】 许波；

【导师】 韩世钧； 李浩然；

【作者基本信息】 浙江大学 ， 化学， 2005， 博士

【摘要】 分子缔合是一个自发的平衡过程,在特定情况下能形成络合物或者分子聚集体,这样的缔合现象广泛存在于生物体系和非生物体系中。对缔合体系的研究既是一个传统的方向,又是一个前沿的研究领域,一直都受到化学家们的广泛关注。 众所周知,实验、理论和模拟是分子热力学研究三角关系中的三个顶点。近年来随着波谱技术的改进和发展,波谱分析手段被广泛用来研究溶液分子层次上的结构、溶液的宏观性质和组成的关系,并且已逐渐成为人们研究分子热力学四面体中的第四个顶点。常用的波谱分析技术主要包括红外光谱(IR)、核磁共振波谱(NMR)、拉曼光谱、紫外可见光谱(UV/vis)、荧光光谱、X-衍射、小角度X-散射、中子散射、质谱(MS)及扫描电镜(SEM)等。 本论文引入统计缔合流体理论(SAFT)中的缔合思想和模型参数,提出了一个关联缔合体系核磁共振化学位移的新模型,对17个缔合体系的57组核磁共振化学位移数据进行了关联,计算了各种氢键的摩尔分数,并且得到了质子在不同缔合情形下的特征化学位移。该模型可以为混合物化学位移随组成的变化提供更加直观的解释,又不需要像化学缔合理论那样假设形成了多少种缔合体,比化学缔合理论要简单,优化参数也较少。同时它又适用于各种不同类型的缔合体系,尤其对于复杂的缔合体系如含水体系有较好的关联结果。 本论文亦将SAFT缔合理论引入到对红外光谱的研究中,用1-2-n缔合模型来关联醇-烃体系羟基伸缩振动的红外吸收数据,但是其中各缔合体的摩尔分数由SAFT缔合理论计算得到,而不需要引入缔合体的平衡常数。这种方法对乙醇与正己烷体系和甲醇与正己烷体系的三个吸收峰的红外吸收数据都关联得较好,由此可以证明1-2-n缔合模型对于醇-烃体系的合理性,同时也表明由SAFT缔合理论求取各种缔合体的摩尔分数的方法是可行的。 本论文还将SAFT缔合理论引入到对拉曼光谱与C-H…O弱氢键的研究中,建立了一个可以描述拉曼光谱C-H伸缩振动频率随浓度变化的SAFT缔合模型,并以此关联了五种含水体系的拉曼光谱C-H伸缩振动频率位移。关联的结果表明SAFT缔合模型能较好地描述混合物的拉曼光谱C-H伸缩振动频率位移性质。更多还原

【Abstract】 Molecular association is a spontaneous equilibrium process by which molecules associate to form complexes or aggregates under specific conditions. These phenomena are widely found in biological and non-biological systems. The study of properties of associating systems is a not only traditional but also preceding field, which attracts chemists at all times.The triangle of experiment, theory and simulation is well known. Recently, spectroscopy was utilized to probe microscopic properties such as intermolecular interactions and solution structure. Spectroscopies such as IR, NMR, Raman, UV/vis, fluorescence spectroscopy, X-ray diffraction, small-angle X-ray scattering, neutron-scattering, MS and SEM have become the fourth vertex on the molecular thermodynamics tetrahedron.In this paper, a new association model based on the Statistical associating fluid theory (SAFT) was proposed to correlate NMR chemical shift of associating systems. 57 sets of data for 17 associating systems were correlated. Mole fractions of various hydrogen bonds were calculated and the characteristic chemical shifts were obtained. The SAFT association model can provide a intuitionistic explaining for the variation of chemical shift with composition of mixtures without assuming how many aggregates are formed. It is simper than chemical association models and the model parameters it needs are fewer. Furthermore, the SAFT association model is applicable for kinds of associating systems. Especially, it is better for dealing with complex associating systems such as aqueous systems.The SAFT association theory was also introduced into the study on IR spectrum. The 1-2-n association model was applied to correlate the IR absorbance data of OH stretching vibration in the alcohol-hydrocarbon systems. But the mole fractions of various aggregates were calculated by SAFT without introducing the equilibrium constants of aggregates. The results of correlation by this method are all good for three absorption bands of ethanol-hexane system and methanol-hexane system. So the feasibility of 1-2-n association model for alcohol-hydrocarbon systems was proved. And it was also proved that the method of calculating mole fractions of aggregates by SAFT is capable.The SAFT association theory is introduced into the study on Raman spectrum and weak hydrogen bonds, too. A SAFT association model was proposed to describe the variation of C-Hstretching vibration frequency of Raman spectrum with composition of mixtures. The C-H stretching vibration frequency data for five aqueous systems were correlated. The results of correlation indicated that SAFT association model described Raman spectrum properties of mixtures very well. Furthermore, the association parameters and characteristic frequency of Raman spectrum of C-H...O weak hydrogen bonds were obtained by the means of correlation, which are important for investigating the properties of weak hydrogen bonds.更多还原