1,4-Dioxane-2,5-dione, 3,6-dimethyl-, (3R,6S)-rel- → Lactide

HRID 1441124

Reaktionsgleichung

Reaktionsgleichung von HRID 1441124
[CH3:1][C@H:2]1[O:9][C:7](=[O:8])[C@H:6]([CH3:10])[O:5][C:3]1=[O:4]>O>[CH3:1][CH:2]1[O:9][C:7](=[O:8])[CH:6]([CH3:10])[O:5][C:3]1=[O:4]

Komponenten

3

Edukt 1

HCID 69503741,4-Dioxane-2,5-dione, 3,6-dimethyl-, (3R,6S)-rel-

Produkt 1

HCID 7272Lactide

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 962WaterLösungsmittel

Versuchsvorschrift

When DL-lactic acid is used as a raw material, the crude lactide has a high meso-lactide content. When the crude lactide is gradually cooled, DL-lactide is precipitated and allowed to persist in the form of crystals in the molten meso-lactide phase and the whole crude lactide assumes a slurry state. The crude lactide in the slurry state is mixed with a substantially equal weight of water and the resultant mixture is immediately cooled to the vicinity of 30° C. for the purpose of preventing DL-lactide from undergoing hydrolysis and kept stirred at this temperature for a period in the range of 30 minutes to one hour, with the result that meso-lactide is dissolved in water and, at the same time, part of the dissolved meso-lactide undergoes hydrolysis. The crystals of DL-lactide are separated by filtration from the water phase and are dissolved in such an organic solvent as acetone or MIBK thereby recrystallizing therefrom to produce easily DL-lactide crystals of high purity.

Aufarbeitung

  1. customhydrolysis
  2. customThe crystals of DL-lactide are separated by filtration from the water phase
  3. dissolutionare dissolved in such an organic solvent as acetone or MIBK
  4. customthereby recrystallizing

Quellen und Nachweise

ORD-Eintrag
ord-f48d2852293247cb9f586e65d77081af
Quelldatensatz
uspto-grants-1996_03
Patentnummer
US05502215

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