Study On Technology Of Halogen-exchange Fluorination Reaction

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.