Reaktion #5632

Reaktionsgleichung

hydroquinone

KOH

KOH

KOH

1,8-dibromooctane

→

product

Ausbeute 99.0%

1,8-BIS(4-HYDROXYPHENOXY)OCTANE

Ausbeute 99.0%

Lösungsmittel

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeA five neck five liter round bottom flask equipped with a mechanical stirrer
2. 2
   Sonstigetwo condensers, and a dropping funnel is purged with nitrogen
3. 3
   Temperaturis slowly heated
4. 4
   Temperaturto reflux under a slow nitrogen
5. 5
   Sonstigepurge
6. 6
   Sonstigea white material precipitates
7. 7
   Temperaturin increasing amounts as the refluxing
8. 8
   SonstigeThe reaction mixture is quenched with one liter of water
9. 9
   workup.ADDITIONthen poured into 4 liters of water
10. 10
    Filtrationfiltered under reduced pressure
11. 11
    Temperaturin warm (50°-70° C.) water
12. 12
    Filtrationfiltered again
13. 13
    Waschenwashed with several portions of boiling water
14. 14
    SonstigeIt is then dried in a vacuum oven at 120° C.
15. 15
    Sonstige310 grams of crude white product is recovered
16. 16
    workup.ADDITIONThe product is treated with 8 liters of boiling ethanol
17. 17
    Filtrationfiltered
18. 18
    Sonstigeto remove oligomers
19. 19
    SonstigeThe filtrate yields a total of 134 grams (41% Yield
20. 20
    SonstigeA final crystallization form 1.1 liters

Vorschrift

A five neck five liter round bottom flask equipped with a mechanical stirrer, two condensers, and a dropping funnel is purged with nitrogen then charged under a nitrogen blanket with 1.1 kg (10.0 moles) hydroquinone, 350 grams deionized water, and 272.0 grams (1.0 moles) 1,8-dibromooctane. The reaction mass becomes a stirable slurry as it is slowly heated to reflux under a slow nitrogen purge. A solution of 184 grams (2.7 moles) 85% KOH pellets in 184 grams water is added dropwise under a nitrogen blanket over a period of 75 minutes. After about one third of the KOH has been added, the slurry has converted to a tea colored solution; then, after most of the KOH has been added, a white material precipitates in increasing amounts as the refluxing is continued an additional 90 minutes. The reaction mixture is quenched with one liter of water then poured into 4 liters of water. The water slurry is acidified with 30% sulfuric acid and filtered under reduced pressure. The filter cake is slurried in warm (50°-70° C.) water, filtered again and washed with several portions of boiling water. It is then dried in a vacuum oven at 120° C. and 310 grams of crude white product is recovered. The product is treated with 8 liters of boiling ethanol and filtered to remove oligomers. The filtrate yields a total of 134 grams (41% Yield based on the dibromide) of white, shiny, "mica-like" crystals more than 95% pure by HPLC peak area nd GPC analysis. A final crystallization form 1.1 liters boiling ethanol gives product more than 99% pure by HPLC peak area (m.p. 151°-153.5° C.) for use in preparation of the copolymer epoxy resin, examples 12, 14, 15, 23 and 24. The ultraviolet absorption spectrum is 30/70 (by volume) methanol/dimethylformamide (DMF) shows a maximum absorption at 297 nm and in 30/70 (by volume) 1.0N KOH in methanol/DMF at 315 nm.

Quelle