Reaktion #1724579

Reaktionsgleichung

hydroquinone

potassium formate

CO2

CO2

potassium carbonate

→

dipotassium 2,5-dihydroxyterephthalate

Ausbeute 87.0%

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeIn a glass reactor having
2. 2
   Sonstigea bottom outlet and equipped with a spiral-shaped stirrer
3. 3
   Sonstigereached 190° C.
4. 4
   workup.ADDITIONwere added to the melt
5. 5
   Sonstigethe slurry was removed from the reactor
6. 6
   Sonstigecrystallized from 3.5 l of boiling water
7. 7
   TemperaturAfter cooling
8. 8
   Filtrationthe product was filtered off
9. 9
   Waschenwashed with ice water
10. 10
    SonstigeDrying under vacuum at 100° C.

Vorschrift

In a glass reactor having a bottom outlet and equipped with a spiral-shaped stirrer and a thermocouple potassium formate (329 g) was melted under vacuum. When the temperature of the melt reached 190° C., the reactor was aerated with CO2 and potassium carbonate (125.04 g, 0.906 mole) and hydroquinone (80.06 g, 0.728 mole) were added to the melt. The reaction mixture was stirred at 200° C. under 1.5 bar CO2 for four and one-half hours. Then 250 ml of water were added to the reaction mixture, and the slurry was removed from the reactor and crystallized from 3.5 l of boiling water. After cooling, the product was filtered off and washed with ice water. Drying under vacuum at 100° C. produced 87% of pale yellow dipotassium 2,5-dihydroxyterephthalate (K2 -2,5-DHTA, 173.77 g, 0.634 mole). The filtrate was boiled down and the residue was reused in a carboxylating reaction using potassium carbonate (95.90 g, 0.695 mole) and hydroquinone (75.06 g, 0.682 mole). According to the above specification, 98% pale yellow K2 -2,5-DHTA (184.31 g, 0.673 mole) was obtained. Repetition of this recycle process using potassium carbonate (94.14 g, 0.682 mole) and hydroquinone (75.16 g, 0.683 mole) according to the above specification produced 95% pale yellow K2 -2,5-DHTA (178.65 g, 0.652 mole).

Quelle