Hydroquinone → 4,4'-[Octane-1,8-diylbis(oxy)]diphenol

Beteiligte Stoffe

Reaktionsschritte

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.

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