Sulfuric Acid → Quinacridone

HRID 1975490Notes

Reaction equation

HRID 1975490 reaction equation
[CH2:1]1[C:6]2[NH:7][C:8]3[C:13]([C:14](=[O:15])[C:5]=2[CH2:4][C:3]2[NH:16][C:17]4[C:22]([C:23](=[O:24])[C:2]1=2)=[CH:21][CH:20]=[CH:19][CH:18]=4)=[CH:12][CH:11]=[CH:10][CH:9]=3.[OH-].[K+].S(=O)(=O)(O)O>CS(C)=O>[CH:20]1[CH:21]=[C:22]2[C:23]([C:2]3[C:3]([NH:16][C:17]2=[CH:18][CH:19]=1)=[CH:4][C:5]1[C:14]([C:13]2[C:8]([NH:7][C:6]=1[CH:1]=3)=[CH:9][CH:10]=[CH:11][CH:12]=2)=[O:15])=[O:24]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 14797Potassium HydroxideHCID 79973Quino(2,3-b)acridine-7,14-dione, 5,6,12,13-tetrahydro-2×

Product 1

HCID 13976Quinacridone

Reagents, catalysts & solvents 1

HCID 679Dimethyl SulfoxideSolvent

Procedure

The oxidation of 6,13-dihydroquinacridone is carried out as described in the Japanese Patent Disclosure JP 54-135821, Example 5. Thus, 10 grams 6,13-dihydroquinacridone are stirred into a mixture of 100 ml dimethyl sulfoxide and 20 grams 33% aqueous potassium hydroxide solution at 110° to 120° and air is then introduced into the vessel at a rate of 90-96 ml/min. for a period of 5 hours. The reaction mixture is cooled and 33% aqueous sulfuric acid is introduced dropwise. The precipitated pigment is filtered and the presscake washed dimethyl sulfoxide-free with water to pH 6 and dried yielding 9.1 grams of a quinacridone pigment. A spectrophotometric analysis shows the product to consist of 0.8% 6,13-dihydroquinacridone, 17.2% of undesirable quinacridonequinone and 78.3% quinacridone. When incorporated into paints or plastics, the pigment shows a dirty red color. Its X-ray diffraction pattern shows the main peaks of known gamma quinacridone and quinacridonequinone.

Workup

  1. additionair is then introduced into the vessel at a rate of 90-96 ml/min. for a period of 5 hours
  2. temperatureThe reaction mixture is cooled
  3. filtrationThe precipitated pigment is filtered
  4. washthe presscake washed dimethyl sulfoxide-free with water to pH 6
  5. customdried

Sources & evidence

ORD record
ord-fed140b41fd348208c14df008cf1065a
Source dataset
uspto-grants-1994_02
Patent number
US05286863

Reaction notes

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