反应详情

温度

125 °C

To a 250 mL round bottomed flask equipped with a heating mantle, overhead agitator, thermometer, condenser, and addition funnel with a tube protruding below the liquid level was added 10.6 g 4,4'-difluorodiphenylmethane (0.051 moles). Agitation was begun and a slurry of 20.5 g MnO2 (0.195 moles) in 30 g water was added to the flask. About 30 g of water were used to wash the MnO2 beaker and were added to the flask. The mixture was allowed to reach about 100° C. at which point 50 g H2SO4 (0.487 moles) were added to the addition funnel. The H2SO4 was then added dropwise into the flask and the reaction temperature slowly rose to about 125° C. when all of the acid had been added. The mixture was heated to maintain the temperature at about 125° C. until gas chromatography showed complete conversion after approximately 12 hours. The reaction mixture was allowed to cool to 100° C. and 50 g toluene were added to the mixture. A slurry of 6 g diatomaceous earth in 30 g water was poured into a vacuum Buchner funnel fitted with No. 42 filter paper to form a filter pre-coat. The contents of the round bottomed flask were then vacuum filtered. 10 g toluene was used to wash the flask and, subsequently, the filter cake. The filter cake was then washed with 100 g toluene heated to about 50° to 70° C. and the filtrate phase separated. The toluene was removed from the organic phase by heating to approximately 65° C. at 10 mm Hg. The 10 g yellow solids assayed as 95% pure 4,4'-difluorobenzophenone for an 84% yield. The solids were recrystallized from a hexane solvent leaving 7.7 g crystalline 4,4'-difluorobenzophenone for a 68% yield.

1. customTo a 250 mL round bottomed flask equipped with a heating mantle, overhead agitator
2. additionthermometer, condenser, and addition funnel with a tube protruding below the liquid level
3. washto wash the MnO2 beaker
4. additionwere added to the flask
5. customto reach about 100° C. at which
6. additionwere added to the addition funnel
7. customslowly rose to about 125° C.
8. additionhad been added
9. temperatureThe mixture was heated
10. customafter approximately 12 hours
11. temperatureto cool to 100° C.
12. customfitted with No
13. filtration42 filter paper
14. customto form a filter pre-coat
15. filtrationvacuum filtered
16. washto wash the flask
17. washThe filter cake was then washed with 100 g toluene
18. temperatureheated to about 50° to 70° C.
19. customthe filtrate phase separated
20. customThe toluene was removed from the organic phase
21. temperatureby heating to approximately 65° C. at 10 mm Hg
22. customThe solids were recrystallized from a hexane solvent