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
- 85 °C
Procedure
382 parts of polyphosphoric acid containg 85.0% P2O5 are metered into a pressure vessel. Then 64.9 parts of 2,5-dianilinoterephthalic acid and 11.5 parts of 2,5-di-(4-toluidino)terephthalic acid are introduced with stirring at from 80 to 90° C. 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 subsequently metered into a second pressure vessel and is hydrolyzed under pressure and with stirring with a mixture of 1721 parts of 30% strength phosphoric acid at 140° C. In the course of hydrolysis the temperature rises to 155° C. The mixture is stirred at 155° C. for 0.5 hours. It is subsequently cooled to 60° C., and the mixed-crystal pigment is filtered off with suction, washed to neutrality with water and dried at 80° C. 68.6 parts of mixed-crystal pigment are obtained. The spectrum is that of the mixed-crystal pigment. The typical reflections of 2,9-dimethylquinacridone are not detectable.
Workup
- temperaturethe mixture is heated at 125° C. for 1 hour, during which ring closure
Sources & evidence
- ORD record
- ord-4ae3add9883c4234a45c0d7b254457c7
- Source dataset
- uspto-grants-2001_06
- Patent number
- US06251553B1
Reaction notes
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