Reacción #1880945

Ecuación de reacción

nitrosylsulfuric acid

sodium hydroxide

hydrochloric acid

hydrochloric acid

2-bromophenol

4-cyanoaniline

→

4-Hydroxy-3-bromo-4′-cyanoazobenzene

Disolventes

water

methanol

water

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONare added
2. 2
   Otrois brought to 0° C.
3. 3
   workup.ADDITIONWhen the addition
4. 4
   Otroto react for a further hour
5. 5
   Filtraciónthe precipitate is filtered off with suction
6. 6
   LavadoThe product is then washed with water
7. 7
   Otrodried

Procedimiento

18.8 g 4-cyanoaniline are heated at 60° C. in 100 ml water. To dissolve the solid, 10 ml conc. hydrochloric acid are added. A further 115 ml hydrochloric acid are then added, the temperature of the solution is brought to 0° C., 52 g nitrosylsulfuric acid are slowly added dropwise and the mixture is stirred for 1 h. This solution is slowly added dropwise to a solution of 27.5 g 2-bromophenol, 100 ml methanol and 100 ml water at 10° C. A pH of 6–6.5 is maintained by simultaneous addition of 10% sodium hydroxide solution. When the addition is complete, the stirred mass is allowed to react for a further hour and the precipitate is filtered off with suction. The product is then washed with water and dried. The yield of 4-hydroxy-3-bromo-4′-cyanoazobenzene is 68 g.

Fuente