【作者】 宋艳杰；

【导师】 屈一新；

【作者基本信息】 北京化工大学 ， 化学工程， 2003， 硕士

【摘要】 随着计算机科学的发展,计算机速度的提高,一些新的方法越来越深入地运用到化学领域。本文运用量子化学的方法进行计算,提出了热力学中重要的参数-无限稀释溶液的活度系数的预测模型;并且通过对大豆异黄酮分子结构的优化计算,提出了对其分离有着指导意义的理论依据。首先,运用从头计算方法中的STO-3G和3-21G 以及半经验方法中的AM1和PM3对300多种化学物质进行几何结构的优化计算,得到这300余种物质的微观的结构性质,对不同类物质的无限稀释溶液的活度系数进行拟合,得到预测方程,并且比较了各种方法在预测无限稀释溶液活度系数上的优劣。另外,本文还运用分子力学方法,对大豆中的功能成分-大豆异黄酮的三种主要存在形式:染料木素(genistein)、大豆黄素(daidzein)、黄豆黄素(glycitein)进行优化计算,得到三种大豆异黄酮的分子体积与溶剂性质,如溶剂溶解度参数和临界压力,及溶液浓度的关系;并且分析键长和键角对体积的影响,从而对于采用何种膜、何种溶剂对大豆异黄酮进行膜分离提供了理论依据。同时这些研究结果也为建立非水相膜分离的机理模型奠定基础。总之,本文的研究工作对于无限稀释活度系数的预测又提出一<WP=4>种新型、简便的预测方法。对于大豆异黄酮的分离提出了一种具有实用性的理论依据,从而可以根据现有的分离膜选择合适的溶剂提取大豆异黄酮使之具有所要求的体积或根据不同的溶剂和浓度选择孔径大小合适的分离膜进行分离,大大减少了实验量,提高了效率。对于今后的研究工作提供了新的思路。更多还原

【Abstract】 Some new methods have been applied in Chemistry more and more deeply with the development of computer science and elevation of computing rate. Computation using Quantum Chemistry was carried out in this paper, and a predicting model for predicting the infinite dilution activity coefficient , an important parameter in thermodynamics. Then we provide the important theoretical basis of isoflavone separation by calculating their structures.In the first place, computation of geometry structure of more than 300 kind of chemical substances were carried out using STO-3G and 3-21G from ab initio and AM1 and PM3 from semi-empirical method. Then the microstructure properties of those chemical substances were obtained. The infinite dilution activity coefficient of different kind of substances were made regression, and prediction equations were obtained. Then different methods were compared in predicting the infinite dilution activity coefficient.Additionally, three kind of isoflavone, such as genistein, daidzein and glycitein, which are the functional component of soybean, were calculated by using molecular mechanics methods. The relations between volume of isoflavone and the properties of solution, such as solubility parameter and critical pressure, have been obtained. The influences of molecular bond length and bond angle on molecular volume were also analyzed. Those provide theoretical basis for using what kind of membrane and solvent for membrane separation of isoflavone. And these results also lay a foundation <WP=6>of building a model of oil phase membrane separation.Generally speaking, a new and simple way of predicting the infinite dilution activity coefficient was suggested in this paper. We provide a theoretical basis for separation of isoflavone practically, on which we can choose suitable solvent for extracting isoflavone, which has specified volume, according to given membrane separation, or choose membrane with suitable pore size according to different solvent and concentration for separation. Thus we can decrease our experimental work and raise our efficiency. Those provide a new idea for our future researches.更多还原