Sulfuric Acid → 3,5-Dichlorosulphanilic acid

HRID 1884803Notes

Reaction equation

HRID 1884803 reaction equation
[Cl:1][C:2]1[CH:8]=[CH:7][CH:6]=[C:5]([Cl:9])[C:3]=1[NH2:4].[S:10](=O)(=[O:13])([OH:12])[OH:11]>O>[Cl:1][C:2]1[CH:8]=[C:7]([CH:6]=[C:5]([Cl:9])[C:3]=1[NH2:4])[S:10]([OH:13])(=[O:12])=[O:11]

Participants

4

Reactant 2

HCID 1118Sulfuric AcidHCID 118462,6-Dichloroaniline

Product 1

HCID 33351473,5-Dichlorosulphanilic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
170 °C

Procedure

2,6-Dichloroaniline (22.0 g; 0.136 mol) was added cautiously to concentrated sulphuric acid (50 ml) under nitrogen, with cooling and stirring. When addition was complete the reaction mixture was heated under nitrogen at 170° C. for 5 hr, then allowed to cool to 50° C. before pouring into cold water (4° C.). The precipitate was filtered and then heated with decolourising charcoal (2 g) in boiling water (500 ml) for 15 min. After filtration the solvent was removed and the crude product was recrystallised from water to give a crystalline solid, which was dried over silica gel overnight, to give 3,5-dichlorosulphanilic acid as a white powder. Yield 13.7 g (42%).

Workup

  1. temperaturewith cooling
  2. additionWhen addition
  3. temperatureto cool to 50° C.
  4. filtrationThe precipitate was filtered
  5. temperatureheated with decolourising charcoal (2 g)
  6. customfor 15 min
  7. filtrationAfter filtration the solvent
  8. customwas removed
  9. customthe crude product was recrystallised from water
  10. customto give a crystalline solid, which
  11. customwas dried over silica gel overnight

Sources & evidence

ORD record
ord-adc0a75720d24c02a508a3c92d3816f1
Source dataset
uspto-grants-2004_07
Patent number
US06767715B2

Reaction notes

Loading…