Hydrochloric Acid → 3,5-Dichloroaniline

HRID 2083269Notes

Reaction equation

HRID 2083269 reaction equation
Cl[C:2]1[C:8]([Cl:9])=[CH:7][C:6]([Cl:10])=[C:5](Cl)[C:3]=1[NH2:4].Cl.S(=O)(=O)(O)O>[Pd].[Ta].C(Cl)Cl>[Cl:9][C:8]1[CH:2]=[C:3]([CH:5]=[C:6]([Cl:10])[CH:7]=1)[NH2:4]

Participants

7

Reactant 3

HCID 313Hydrochloric AcidHCID 1118Sulfuric AcidHCID 189982,3,5,6-Tetrachloroaniline

Product 1

HCID 122813,5-DichloroanilineYield 89%

Reagents, catalysts & solvents 3

HCID 23938PalladiumCatalystHCID 23956TantalumCatalystHCID 6344DichloromethaneSolvent

Procedure

57.7 g (0.25 mol) of 2,3,5,6-tetrachloroaniline, 250 ml of 36% strength aqueous solution of hydrochloric acid, 5 ml of concentrated sulphuric acid and 5 g of a 5% strength palladium/active charcoal catalyst are introduced into an 0.7 l autoclave made of tantalum. The autoclave is flushed first with nitrogen and then with hydrogen. The dechlorination is carried out over the course of 2 hours at 250° C and a hydrogen pressure of 200 atmospheres gauge. After the reaction, the catalyst is filtered off and washed twice with hot water. The reaction solution together with the wash water is rendered alkaline and warmed. After cooling, the reaction product is extracted twice with 150 ml of methylene chloride. After distilling off the methylene chloride, and subsequent fractional distillation, 36 g of 3,5-dichloroaniline (yield: 89% of theory) are obtained.

Workup

  1. customThe autoclave is flushed first with nitrogen
  2. customis carried out over the course of 2 hours at 250° C
  3. customAfter the reaction
  4. filtrationthe catalyst is filtered off
  5. washwashed twice with hot water
  6. temperaturewarmed
  7. temperatureAfter cooling
  8. extractionthe reaction product is extracted twice with 150 ml of methylene chloride
  9. distillationAfter distilling off

Sources & evidence

ORD record
ord-13488666a3fc4e5082c09fd6258b8d0d
Source dataset
uspto-grants-1978_04
Patent number
US04085141

Reaction notes

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