Hydrochloric Acid → 4-Amino-2,3-dichlorophenol

HRID 1955371Notes

Reaction equation

HRID 1955371 reaction equation
N([O-])=O.[Na+].Cl.[NH2:6]C1C=CC=CC=1.[Cl:13][C:14]1[C:19]([Cl:20])=[CH:18][CH:17]=[CH:16][C:15]=1[OH:21].[OH-].[Na+].O.NN>O.[Ni]>[Cl:20][C:19]1[C:14]([Cl:13])=[C:15]([OH:21])[CH:16]=[CH:17][C:18]=1[NH2:6]

Participants

9

Reactant 6

HCID 313Hydrochloric AcidHCID 6115AnilineHCID 113342,3-DichlorophenolHCID 14798Sodium HydroxideHCID 24654Hydrazine hydrate (1:1)HCID 23668193Sodium Nitrite

Product 1

HCID 98775294-Amino-2,3-dichlorophenolYield 94.4%

Reagents, catalysts & solvents 2

HCID 935NickelCatalystHCID 962WaterSolvent2×

Procedure

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.

Workup

  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

Sources & evidence

ORD record
ord-a25b83e776854117a3ec35da24a8fc6e
Source dataset
uspto-grants-2000_09
Patent number
US06124504

Reaction notes

Loading…