【作者】 姜辉；

【导师】 李浩然； 王从敏；

【作者基本信息】 浙江大学 ， 化学工程与技术， 2006， 博士

【摘要】 化学科学与化学工程技术的进步为国民经济增长、人民群众生活水平的提高与社会的发展做出了十分重要的贡献。但另外一方面，传统的化学工业也产生了大量的工业污染，造成了严重的环境问题，危及到可持续发展。上世纪90年代中期逐步发展起来的绿色化学从原理和方法上给传统的化工生产带来了显著的变化，是近年来化学工业尤其是精细化工研究的热点和重点。本论文以绿色化学的基本原理和思路为指导，以结构简单、价格便宜具有十分广阔的可工业化前景的简单铵型离子液体为主要手段，对维生素E及其中间体绿色化学问题进行研究。论文首先对维生素E中间体2，2—二烷氧基丙烷的合成进行了研究。针对传统方法中需要用到挥发性的有机溶剂以及对设备造成腐蚀的氯化氢酸性催化剂的不足，运用简单铵型离子液体为反应介质和催化剂，替代传统方法需要用到挥发性的有机溶剂以及对设备造成腐蚀的氯化氢酸性催化剂，减小了对环境造成的污染。论文第二部分以2—烷氧基丙烯与脱氢芳樟醇为原料，在酸性简单铵型离子液体中经过Saucy-Marbet反应制备维生素E中间体假紫罗兰酮。假紫罗兰酮是维生素E侧链原料异植物醇的关键中间体。简单铵型离子液体在反应中起到催化剂的作用。引入酸性离子液体，替代了传统方法中需要用到的挥发性有机溶剂，提高了反应的选择性。在成功进行了2，2—二烷氧基丙烷和假紫罗兰酮的研究后，我们进而采用简单铵型离子液体以异植物醇与三甲基氢醌为原料，经过缩合反应合成维生素E，取得了良好的实验结果。反应结束后，在反应体系中加入水，由于维生素E不溶于水，而简单铵型离子液体易溶于水，从而简单地实现了产物的分离。离子液体能够循环重复套用。论文的第三部分对2，2—二烷氧基丙烷裂解生成2—烷氧基丙烯反应进行了系统的实验与理论研究。首先合成了三种新型DMF型简单铵型离子液体，并将其应用于裂解反应。针对传统裂解反应温度高、副反应多、需要用到挥发性的有机溶剂、产物难于提纯等缺点，对2，2—二烷氧基丙烷裂解反应从气相和凝聚相反应两个方面进行了实验研究。在实验工作基础上，运用量子化学结合反应动力学计算对裂解反应进行了理论研究。研究发现，四元环的过渡态是烷氧基丙烷裂解反应的主反应通道。随后的反应动力学研究表明，在气相反应中，低温区强烈的量子隧道效应是2，2—二乙烷氧基丙烷和2，2—二甲烷氧基丙烷反应体系反应速率常数比值趋近于1的主要因素。在凝聚相中动力学研究发现，考虑电子相关的溶剂效应是使2，2—二乙烷氧基丙烷和2，2—二甲烷氧基丙烷反应体系在溶液相中裂解反应速率常数趋近于1的主要因素，同时由于反应在低温区(＜400K)进行，强烈的量子隧道效应又是不得不考虑的另外一个因素。综合考虑溶剂效应与量子隧道效应，很好的解释了为什么2，2—二乙烷氧基丙烷和2，2—二甲烷氧基丙烷在凝聚相中(液相)裂解反应有大致相同的反应速率的实验现象。更多还原

【Abstract】 Green chemistry is the design of chemical products and processes that reduce or eliminate the use and generation of poisonous materials. Current and future chemists are being attracted to design products and processes with an increased awareness for environmental pollutions. So far, chemistry and chemical engineering have been regarded as the major contributors to economic progress over the past century, and yet the chemical industry is often taken to task for many serious environmental problems. One of the most attractive concepts for pollution protection is green chemistry: it is better to prevent waste than to treat or clean up waste after it is formed.Vitamin E is the most important antioxidant in the biological system and is widely used as an additive for foodstuffs, pharmaceuticals, cosmetics and animals feeds. It is reported that more than 20,000 tons Vitamin E is produced in our country annually. On the other hand, a lot of wastes are formed.In order to reduce or eliminate the use and generation of poisonous materials during the Vitamin E and its intermediates synthesis and achieve clean production we report here that the simple ammonium ionic liquids have been used as dual catalyst and environmental benign reaction medium for Vitamin E and its intermediates: dialkoxypropanes, 2-alkoxypropenes and pseudoionone preparation, eliminating the need for a volatile organic solvents and poisonous hydrogen chloride catalysts. These simple ammonium ionic liquids are air and water stable, easy to synthesis from amine and acid, and relatively cheap, which makes them suitable for industrial application. The results clearly demonstrate that these ionic liquids can be easily separate and reused without losing their activity. These ionic liquids provide a good alternative for industrial preparation of Vitamin E and its intermediates.The experimental results show that the decompositions of 2,2-Dimethoxypropane （DMP） and 2,2-Diethoxypropane （DEP） have nearly identical rate ratio of 2-methoxypropene （MPP） and 2-ethoxypropene （EPP） in ionic liquids. The yields ratio of MPP/methanol and EPP/ethanol were nearly 1.0. Thefour-center cyclic transition state was found in B3LYP Density Functional Theory of level. Surprisingly, the experimental observations and theoretical rate constants ratio (k_DEP/k_DMP) appeared to differ about ten magnitudes at the experimental temperatures range. Further dynamics study indicated that the significant tunneling effect played an important role in the identical rate constants ratio of the decomposition reactions at low temperatures range. Further dynamics studies in the condensed phase show that the solvent effect and tunneling effect are particularly important and are the main contributors to the identical rate constant ratio which observed in our experiment of the decomposition reactions at low temperatures （below 400K）. Due to the introduction of condensed phase, the decomposition reactions that formerly performed at high temperatures range could take place at relatively low temperature. To such kind of decomposition reactions in the condensed phase, the solvent effect and tunneling effect should be taken into account. More accurate solvent model and methods for computing the solvent effect and tunneling effect are underway in our group.All in all, experimental and theoretical study on the preparation of Vitamin E and its intermediates aim to reduce or eliminate the use and generation of poisonous materials. We expect that these methods are applicable to investigate more important phenomena in green chemistry.更多还原