【作者】 梁政勇；

【导师】 吕春绪；

【作者基本信息】 南京理工大学 ， 应用化学， 2008， 博士

【摘要】 卤素交换氟化反应是制备含氟化合物的重要方法之一,具有原料来源广、工艺简单、易于工业化等优点。本研究以含氟化合物的开发为目的和主线,并以此带动相应氟化反应理论与新技术的研究。在加热源、氟化试剂、反应溶剂、相转移催化剂、副反应以及宏观反应动力学等方面进行了较为系统地研究。研究表明,微波是一种节能高效的加热方式,在微波作用下的卤素交换氟化反应具有反应速度快、转化率高、选择性好的优点,其反应时间可较常规加热缩短50%以上;同时也系统地研究了氟化剂种类及制备方式对其反应活性的影响,并利用微波加热的膨化作用制备出了一种活性较高的KF,其活性与喷雾干燥KF相差不大;溶剂对反应具有重要的作用,在此系统地研究了强极性非质子溶剂和中等极性非质子溶剂的应用情况,发现一些中等极性的非质子溶剂如硝基芳烃和氯代芳烃类溶剂在氯代苯甲醛类化合物的氟化反应中具有比强极性非质子溶剂更好的使用效果。此外,对绿色反应溶剂—离子液体在氟化中的应用也作了初步研究,研究结果表明离子液体介质的氟化反应具有反应效率高、体系简单、产物易分离的特点。更为重要的是,离子介质有机合成技术和微波有机合成技术具有很好的兼容性,一方面,离子液体可以在微波作用下高效、快速合成。另一方面,离子液体可以显著提高氟化反应体系的微波吸收效果,加快反应速率;相转移催化剂对卤素交换反应来说几乎是不可或缺的,季鎓盐、聚醚都可依具体情况加以选择应用,但将二者按适当的比例复配,则可以产生“协同效应”,其在氯代苯甲醛及二苯甲酮类化合物的氟化中具有显著的效果。高分子相转移催化剂往往具有稳定性高、催化性能好的特点,作者所合成的高分子咪唑盐相转移催化剂在硝基氯苯类化合物的氟化反应中表现出比常规相转移催化剂更好的催化效果;采用副反应放大和GC-MS联用技术研究了副反应,发现副产物来源主要是水分、溶剂以及反应物本身。系统地研究了常规加热和微波加热下的反应动力学,得出了一些重要的基础数据,并依据过渡态理论探讨了反应物结构与活性的关系以及微波加速机理中“非热效应”的存在性。但受目前技术条件的限制,还不能就微波“非热效应”的存在性给予十分肯定的答复。更多还原

【Abstract】 Helogen-exchange fluorination is one of the main and efficient methods to synthesize fluorinated compounds with the advantages of wide material, simple technique and being prone to industrialization. The aims of our research are exploitation of fluorinated compounds and probing into new fluorinating technology. The research is involved in heat resources, fluorinating agents, solvents, phase-transfer catalysts, side reactions and kinetics, etc.The application results from fluorination showed microwave heating could accelerate chemical reactions markedly. The reaction time could be shortened 50% at least than that of conventional heating. The relationship between fluorinating agents’ structure and their activity was studied systematically. In addition, an anhydrous KF with higher activity was prepared by using expansion effect of microwave heating. As we known, solvents were very important to reaction. The comprehensive study showed some less polar aromatic solvents could be used as dipolar solvents. In addition, they had better effect than dipolar solvents in some occasions, such as fluorination of chlorobenzaldehydes and chlorinated diphenyl ketones etc. The primary applications of ionic liquids were also studied which indicated reactions with ionic liquids as solvents were more efficient and simple. Further more, synthesis technology in ionic liquids have much compatible with microwave induced synthesis technology. On the one hand, ionic liquids could be prepared efficiently under the irradiation of microwave. On the other hand, ionic liquids could improve system’s absorbability of microwave. PTCs were essential to halogen-exchange fluorination. Oniums and polyethers were used selectively. Nevertheless, the mixtures of them were more active because of "synergistic interactions". Polymer imidazole salt were a new kind of polymer phase transfer catalyst, which had the superiority of convenience for preparation, good thermal stability and high catalytic activity in fluorination of chloro-nitrobenzenes. Side reactions were studied by the means of magnification of side reactions and GC-MS. Many by-products were detected in reaction mixture and considered to be formed deriving from water, solvents and reactants themselves.Kinetics studies under conventional heating and microwave heating were studied and got some important data. In addition, the relationship between reactants and their activity and existence of "non-thermal effect" of microwave discussed according to the theory of transition station. Unfortunately, It hasn’t been confirmed that whether there was non-thermal effect or not under the irradiation of microwave for the limit of present technology.更多还原