Dimethyl Succinate → 1,4-Cyclohexanedicarboxylic acid, 2,5-dioxo-, 1,4-dimethyl ester

Temperatur

76 °C

To a stirred solution of dimethyl succinate (400.1 g., 98.7% purity, 2.7 mole) and dry methanol (13 g., 0.4 mole) at 30° C. under nitrogen is added over 1.5 hour a stirred slurry of finely divided sodium (22.1 g., 0.96 mole) in dimethyl succinate (83.4 g., 0.57 mole). The temperature rises to 45° C. maximum. The mixture is heated to 76° C. and the methanol stripped off over two hours. Additional dimethyl succinate is added (200 g., 1.38 mole) to maintain the fluidity of the reaction. On completion of methanol distillation, methanol is added (400 g., 12.5 mole) and the mixture cooled to 30° C., filtered and the excess dimethyl succinate washed out with dry methanol. The resulting filtercake is reslurried in methanol and added to 15% aqueous sulfuric acid (330 g.), cooled to 24° C. then filtered, washed with water to remove the sodium sulfate, and dried. A yield of 81% of theory dimethyl succinylsuccinate is obtained.

1. customrises to 45° C.
2. temperatureto maintain
3. customthe fluidity of the reaction
4. distillationOn completion of methanol distillation, methanol
5. additionis added (400 g., 12.5 mole)
6. temperaturethe mixture cooled to 30° C.
7. filtrationfiltered
8. washthe excess dimethyl succinate washed out with dry methanol
9. additionadded to 15% aqueous sulfuric acid (330 g.)
10. temperaturecooled to 24° C.
11. filtrationthen filtered
12. washwashed with water
13. customto remove the sodium sulfate
14. customdried

ORD-Eintrag

ord-4c912806ece04745b5bfcd65dd0ab8ea

Quelldatensatz

uspto-grants-1998_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05783723