Reaktion #550985

Reaktionsgleichung

DTTA

phosphoric acid

2,5-di(p-tolylamino)terephthalic acid

→

2,9-dimethylquinacridone

Ausbeute 15.0%

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.DISSOLUTIONto dissolve each portion
2. 2
   workup.ADDITIONbefore adding another one
3. 3
   SonstigeThe temperature is kept below 60° C. by external water bath
4. 4
   Temperaturcooling
5. 5
   Sonstigethe solution is transferred into a 500 ml round-bottom flask
6. 6
   Sonstigeequipped with mechanical stirrer, CaSO4 drying tube, N2 inlet
7. 7
   Temperaturthermometer, and heated to 100° C. within 45 minutes
8. 8
   workup.STIRRINGStirring
9. 9
   workup.WAITis continued for 10 minutes
10. 10
    FiltrationThe precipitate is filtered
11. 11
    Waschenwashed acid-free with water
12. 12
    workup.ADDITIONby adding 50 wt % aqueous NaOH solution
13. 13
    workup.STIRRINGwith stirring
14. 14
    Temperaturis heated
15. 15
    workup.WAITkept at 60° C. for 15 minutes
16. 16
    workup.STIRRINGwith continued stirring
17. 17
    Filtrationfiltered
18. 18
    Temperaturwhile warm
19. 19
    WaschenThe filter cake is washed with water
20. 20
    Sonstigedried in a vacuum oven at 70°-80° C.

Vorschrift

Two hundred ml of polyphosphoric acid and 100 ml of 85% phosphoric acid are mixed in a mechanically stirred beaker and allowed to cool to 40° C. Thirty grams of 2,5-di(p-tolylamino)terephthalic acid (DTTA) are added in small portions, successively, under intense agitation by Gifford-Wood homogenizer. Care is taken to dissolve each portion before adding another one. The temperature is kept below 60° C. by external water bath cooling. After having dissolved all of the DTTA, as ascertained by dipping a glass rod into the viscous reaction medium and examining for solid particles clinging to the rod, the solution is transferred into a 500 ml round-bottom flask equipped with mechanical stirrer, CaSO4 drying tube, N2 inlet and thermometer, and heated to 100° C. within 45 minutes with stirring. The temperature is held at 100° C. for 45 minutes. The solution develops an orange-brown fluorescense during this time. The solution is poured into 2 l of water with mechanical stirring, generating a dark-colored precipitate. Stirring is continued for 10 minutes. The precipitate is filtered, washed acid-free with water and suspended in 2 l of H2O. The suspension is made basic with a pH of 12 by adding 50 wt % aqueous NaOH solution with stirring, is heated, kept at 60° C. for 15 minutes with continued stirring and filtered while warm. The filter cake is washed with water and dried in a vacuum oven at 70°-80° C. to give 4.0 g (15% yield) of apparently 2,9-dimethylquinacridone by-product. The filtrate and wash water combined are acidified with acetic acid to a pH of 4, with stirring. The resulting red precipitate is filtered, washed acid-free with water and dried overnight at 70°-80° C. under vacuum and slight N2 purge to give 22.3 g (78% yield) of red 2-(p-tolyl)amino-3-carboxy-7-methyl-9(10H)acridinone (TMCA).

Quelle