O-Cresol → 4-Bromo-2-methylphenol

Temperatur

2 °C

Into a 5-liter reaction flask was charged 324g of o-cresol (3 moles) and 1200 g of methylene chloride. The reaction was cooled to 2° C. and 480 g (3 moles) of bromine dissolved in 960 g of methylene chloride was run in slowly over a 7-hour period. The next day, the cooling bath was removed and a heating mantle was attached. 1 liter of Isopar G (trademark of Exxon for a hydrocarbon fraction) was added and distillation of the methylene chloride was begun under water aspirator vacuum. Eventually the distillation rate slowed and the pot temperature rose to 70° C. The still head temperature dropped from 35° C. to 28° C. The solution was poured into a beaker and cooled to room temperature without stirring. In the morning, the solution was cooled to -5° C. and filtered. There was recovered 440 g of 4-bromo-o-cresol melting at 61-64° C. in 78% yield.

1. customInto a 5-liter reaction flask
2. customslowly over a 7-hour
3. customThe next day, the cooling bath was removed
4. addition1 liter of Isopar G (trademark of Exxon for a hydrocarbon fraction) was added
5. distillationdistillation of the methylene chloride
6. customrose to 70° C
7. additionThe still head temperature dropped from 35° C. to 28° C
8. additionThe solution was poured into a beaker
9. temperaturecooled to room temperature
10. temperatureIn the morning, the solution was cooled to -5° C.
11. filtrationfiltered
12. customThere was recovered 440 g of 4-bromo-o-cresol melting at 61-64° C. in 78% yield

ORD-Eintrag

ord-43ba83c04e004362b28d9f64b029f504

Quelldatensatz

uspto-grants-1987_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04642383