PRODUCTION OF PENTAFLUOROBENZONITRILE

摘要

PURPOSE:To obtain the titled compound in high yield at a low cost, by reacting pentachlorobenzonitrile with an alkali metal fluoride powder at a specified reaction molar ratio in an autoclave under given reaction conditions, and distilling fractionally the reaction mixture. CONSTITUTION:A partial fluoride expressed by the formula (m is 1-4; n=5-m) is added to pentachlorobenzonitrile and an alkali metal fluoride powder, and the resultant mixture is weighed to give 1-3 times equivalent molar ratio between the alkali metal fluoride and the total of pentachlorobenzonitrile and partial fluoride. The resultant mixture is reacted at 360-450 deg.C for 6-40hr in an autoclave. The contents in the autoclave are then discharged in the state of a high- temperature gas and led to a condenser, and the resultant liquid is then fractionally distilled to afford the aimed compound. The remaining unreacted raw material and compound of formula I as part of the raw material are circulated through the reaction system. The molar ratio of the raw material adjusted to the above-mentioned range and addition of the partial fluoride expressed by the formula in a small amount accelerate the reaction to improve the utilization ratio of the raw material.