2. 5kg 3,4,5_trifluorophenol crude, of which toluene content is 2%, the content of near-boiling impurity 3,5_difluorophenol is 0. 05%, 3,4-difluorophenol content is 0. 03%, 2,4-difluorophenol content is 0. 025%, 2,3,5-trifluorophenol content is 0. 07%, 2, 3,4-trifluorophenol content is 0. 042%, 2,4,6-trifluorophenol content is 0. 01%. The content of 2,3,4-trifluorophenol was 0. 042%, 2,4,6-trifluorophenol was 0. 01 %, and the content of 3,4,5-trifluorophenol was 97.8%.
The crude material was put into a 5L distillation kettle, and p-tert-butyltoluene was added 1.5kgo to 100mmHg full reflux Ihr, and then p-tert-butyltoluene fraction was collected from the top of the tower at a reflux ratio of 1 1. After the collection, the tower kettle sampling GC analysis, toluene content is not detected, 3,5- difluorophenol contains 50ppm, 3,4- difluorophenol 62ppm, 2,4- difluorophenol 2ppm, 2,3,5-trifluorophenol 3ppm, 2,3,4-trifluorophenol 2ppm, will be evaporated from the top of the tower to get the high-purity 3,4,5-trifluorophenol weighing 2.2kg, content of 99.98%, distillation yield of 99.9%, distillation yield of 1:1 reflux ratio. . 98 %, and the distillation yield was 89. 97 %.
