如何除去wittig反应中生成的三苯氧磷呢? 摘录的供您参考 ethyl 4,4,4-trifluorotetrolate. a 1-l, three-necked, round-bottomed flask is equipped with an efficient magnetic stirrer, a heating mantle, a thermocouple (note 7 ) and a large bore gas exit tube (figure 1 , note 8 ). to this flask are added 200 g (0.45 mol) of ethyl 4,4,4-trifluoro-2-(triphenylphosphoranylidene)acetoacetate and 40 g of potassium carbonate (note 9 ). the gas exit tube is connected to a dewar condenser, modified with a side arm connection, which has a round-bottomed flask for collection of the product in a dry ice-acetone bath. a second trap is placed between the reaction setup and the vacuum pump, all the traps are cooled with dry ice-acetone, and the system is evacuated to 1–2 mm. the reaction flask is carefully heated to 150°c (note 10 ) at which point the phosphorane melts and the acetylene evolution begins. the molten phosphorane is stirred and heated from 160°c to 220°c over a period of 5 hr. heating is carefully increased during the reaction in order to control the rate of distillation of the acetylenic product. from the round-bottomed flask in the cold trap is obtained 65–67 g (87–89%) of a clear, slightly yellow, liquid. the thermolysis product is dried with magnesium sulfate and filtered through celite. distillation at atmospheric pressure through a short-path distillation apparatus affords about 1.0 g of forerun and 59–61 g (79–82%) of ethyl 4,4,4-trifluorotetrolate as an analytically pure, colorless liquid, bp 760 97–100°c (note 11 ). 查看更多
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