Hydrochloric Acid → 2,5-Dihydroxyterephthalic acid

Temperatur

25 °C

Under nitrogen, 2.00 g (8.51 mmol) of 2,5-dichloroterephthalic acid was combined with 10 g of H2O. 0.938 g (8.85 mmol) of Na2CO3 was then added. The mixture was heated to reflux with stirring for 30 min, remaining under a nitrogen atmosphere. Another 1.31 g (12.34 mmol) of Na2CO3 was added to the reaction mixture and reflux was continued for 30 min. Separately, 12 mg of CuBr and 24 mg of rac-trans-N,N′-dimethylcyclohexane-1,2-diamine (Ligand F) were combined with 2 mL H2O under nitrogen. The resulting mixture was stirred under an air atmosphere until the CuBr was dissolved to give a deep purple solution. This solution was added to the stirred reaction mixture via syringe at 80° C. under nitrogen and stirred for 20 h at 80° C. After cooling to 25° C., the reaction mixture was acidified with HCl (conc.), producing a dark yellow precipitate. The yellow precipitate was filtered and washed with water. After drying, a total of 1.59 g (8.03 mmol, 94% yield) 2,5-dihydroxyterephthalic acid was collected. The purity was determined by 1H NMR to be 95%.

1. temperatureThe mixture was heated
2. temperatureto reflux
3. temperaturereflux
4. waitwas continued for 30 min
5. dissolutionwas dissolved
6. customto give a deep purple solution
7. additionThis solution was added to the stirred reaction mixture via syringe at 80° C. under nitrogen
8. stirringstirred for 20 h at 80° C
9. customproducing a dark yellow precipitate
10. filtrationThe yellow precipitate was filtered
11. washwashed with water
12. customAfter drying

ORD-Eintrag

ord-bed48b34cd42411db5f43db5f26e8766

Quelldatensatz

uspto-grants-2009_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07538244B2