2,5-Dianilinoterephthalic acid → Quinacridone
Reaction equation
[NH:1]([C:8]1[CH:16]=[C:15]([C:17](O)=[O:18])[C:14]([NH:20][C:21]2[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=2)=[CH:13][C:9]=1[C:10](O)=[O:11])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C1(C)C=CC(NC2C=C(C(O)=O)C(NC3C=CC(C)=CC=3)=CC=2C(O)=O)=CC=1>>[CH:24]1[CH:25]=[C:26]2[C:17]([C:15]3[C:14]([NH:20][C:21]2=[CH:22][CH:23]=1)=[CH:13][C:9]1[C:10]([C:7]2[C:2]([NH:1][C:8]=1[CH:16]=3)=[CH:3][CH:4]=[CH:5][CH:6]=2)=[O:11])=[O:18]Participants
Conditions
- Temperature
- 125 °C
Procedure
A stirred vessel is charged with 450 parts of polyphosphoric acid containing 83.0% P2O5. Then 37.5 parts of 2,5-dianilinoterephthalic acid and 112.5 parts of 2,5-di-(4-toluidino)terephthalic acid are introduced at 125° C. with stirring, and the mixture is heated at 125° C. for 1 hour during which ring closure takes place to form the quinacridone. The reaction mixture is then metered over the course of 5 minutes into a second stirred vessel containing 1431 parts of 70% strength phosphoric acid and is hydrolyzed at 25° C. with stirring. During this procedure the temperature rises to 60° C. Following the hydrolysis, the phosphoric acid strength is 80%. The mixture is heated to 120° C. and stirred at 120° C. for 5 hours. It is cooled to 90° C. and the hydrolysis mixture is poured into 6000 parts of water at 25° C. with stirring. Thereafter, the mixture is heated to 90° C. and the mixed-crystal pigment is filtered off with suction, washed to neutrality with water and dried at 80° C.
Sources & evidence
- ORD record
- ord-e6fbd1aafa0241349ab15a4211021e92
- Source dataset
- uspto-grants-2001_06
- Patent number
- US06241814B1
Reaction notes
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