微波促进卤素交换氟化反应合成硝基氟苯类化合物:溶剂的选择及其在微波场中的性质

Microwave-promoted Halogen-exchange Reaction for Preparation of Fluoronitrobenzenes:Selection of Solvents and Their Properties in Microwave Field

微波加热在卤素交换氟化反应中的应用结果显示其具有反应时间短和产率高的优点。在微波加热下 ,对硝基氟苯、邻硝基氟苯、3 氯 4 氟硝基苯和 5 氯 2 氟硝基苯可以从相应的硝基氯苯于十六烷基三甲基溴化铵催化下通过卤素交换氟化反应制备 ,分别得到 91 1%、44 4%、92 1%和 5 3 9%的产率 ,都好于相同条件下常规加热的产率 ,反应速率分别提高到常规加热的 6倍、6倍、12倍和 2 1倍。溶剂研究得出此反应中所用溶剂的优劣顺序为 :二甲亚砜 >N ,N 二甲基乙酰胺 >环丁砜 >N 甲基 2 吡咯烷酮 >N ,N

The application of microwave technology in halogen-exchange reaction has many merits, such as short reaction time and high yield.p-Fluoronitrobenzene, o-fluoronitrobenzene,3-chloro-4-fluoronitrobenzene and 5-chloro-2-fluoronitrobenzene were prepared from corresponding chloronitrobenzenes catalyzed by cetyltrimethylammonium bromide under microwave irradiation in 91.1%,44.4%,92.1% and 53.9% yield respectively,all of them better than those with traditional methods under the same reaction conditions.The reaction rates were also increased by 6,6,12 and 21 times respectively against ordinary heating.Experimental results showed that the solvents used in this reaction in the order of superiority are:dimethyl sulfoxide >sulfolane >N-methyl-2-pyrrolidone >N,N-dimethyl acetamide >N,N-dimethyl formamide.