反应详情

At 0-5° C., a solution of 7.3 g (0.105 mol) of NaNO2 in 22 ml of H2O is added dropwise to 50 ml of aqueous HCl (15%) and 9.3 g (0.1 mol) of aniline in a 250 ml two-neck flask fitted with internal thermometer and magnetic stirrer. After 30 min, this diazonium salt solution is added slowly at 5-10° C. to a solution of 16.4 g (0.1 mol) of 2,3-dichlorophenol and 12.4 g (0.31 mol) of NaOH in 100 ml of H2O. The suspension is allowed to warm to room temperature and stirred for a further 1 h, and 0.5 g of Raney nickel are then added. 6 g (0.06 mol) of hydrazine hydrate are then added at 40-50° C. over a period of 2 h. After the addition, stirring is continued for 1 h and the solution is filtered over a bed of silica gel. With cooling, the solution is then adjusted to pH=5.7 with 20% strength HCl. The precipitated solid is washed with 50 ml of water and 50 ml of toluene and dried. 16.8 g (94.3% of theory) of pure 2,3-dichloro-4-hydroxyaniline are obtained.

1. customfitted with internal thermometer and magnetic stirrer
2. additionAfter the addition
3. stirringstirring
4. waitis continued for 1 h
5. filtrationthe solution is filtered over a bed of silica gel
6. temperatureWith cooling
7. washThe precipitated solid is washed with 50 ml of water and 50 ml of toluene
8. customdried