Hydrochloric Acid → N,N'-Diacetyl-3,3'-dimethylbenzidine

HRID 2379249

Reaction equation

HRID 2379249 reaction equation
[CH3:1][C:2]1[CH:3]=[C:4]([C:9]2[CH:14]=[CH:13][C:12]([NH2:15])=[C:11]([CH3:16])[CH:10]=2)[CH:5]=[CH:6][C:7]=1[NH2:8].Cl.[C:18](OC(=O)C)(=[O:20])[CH3:19].[C:25]([O-])(=[O:27])[CH3:26].[Na+]>O>[CH3:16][C:11]1[CH:10]=[C:9]([C:4]2[CH:5]=[CH:6][C:7]([NH:8][C:25](=[O:27])[CH3:26])=[C:2]([CH3:1])[CH:3]=2)[CH:14]=[CH:13][C:12]=1[NH:15][C:18](=[O:20])[CH3:19]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 7918Acetic AnhydrideHCID 8413o-TolidineHCID 517045Sodium Acetate

Product 1

HCID 626583N,N'-Diacetyl-3,3'-dimethylbenzidine

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
90 °C

Procedure

3,3'-Dimethyl-4,4'-diaminobiphenyl (12.74 grams, 0.12 --NH2 equivalent) is ground to a fine powder and added to a beaker containing stirred, 90° C. deionized water (1200 milliliters). After two minutes, aqueous 36.5% hydrochloric acid (12.00 grams, 0.12 mole) is added to the stirred, 90° C. suspension. The solution which formed in six minutes is cooled to 70° C. Acetic anhydride (15.04 grams, 0.473 mole) is added to the stirred solution and mixed therein for 20 seconds before addition of an aqueous sodium acetate solution (prepared by dissolution of anhydrous sodium acetate [19.69 grams, 0.24 mole] in deionized water [60.0 grams]). After thoroughly stirring the white slurry, it is maintained at 4° C. for 16 hours, followed by filtration to remove the precipitated product. The recovered filter cake is washed with two portions (150 milliliters) of deionized water then dried in a vacuum oven at 60° C. and 5 mm Hg to a constant weight of 16.92 grams. The product is recovered as a white crystalline powder. Fourier transform infrared spectrophotometric analysis of a potassium chloride pellet of the product confirms the product structure: disappearance of the absorbances observed for the --NH2 group, appearance of solid state >NH stretching absorbances at 3283 (3183 slight shoulder) cm-1, a solid state amide I carbonyl stretching absorbance at 1656 cm-1, a solid state amide II carbonyl stretching absorbance at 1516 cm-1 (masking the aromatic ring absorbance) and a C--H out-of-plane bending vibration at 819 cm-1 due to the para-disubstituted aromatic rings. Proton nuclear magnetic resonance spectroscopy further confirms the product structure.

Workup

  1. additionadded to a beaker
  2. additioncontaining
  3. customThe solution which formed in six minutes
  4. temperatureis cooled to 70° C
  5. additionmixed
  6. stirringAfter thoroughly stirring the white slurry, it
  7. temperatureis maintained at 4° C. for 16 hours
  8. filtrationfollowed by filtration
  9. customto remove the precipitated product
  10. filtrationThe recovered filter cake
  11. washis washed with two portions (150 milliliters) of deionized water
  12. customthen dried in a vacuum oven at 60° C.
  13. customThe product is recovered as a white crystalline powder

Sources & evidence

ORD record
ord-a598688610af4e6c8904a9ce1aa5ad95
Source dataset
uspto-grants-1994_11
Patent number
US05360884

Linked notes

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