Hydroquinone → 1,4-Bis(4-hydroxyphenoxy)butane

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 1.25 kg (11.36 moles) hydroquinone, 350 grams deionized water, and 231.25 grams (1.07 moles) 1,4-dibromobutane. The reaction mass becomes a stirable slurry as it is slowly heated to reflux under a slow nitrogen purge. A solution of 180 grams (2.7 moles) 85% KOH pellets in 180 grams water is added dropwise under a nitrogen blanket over a two hour period. 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 hour. The reaction mixture is quenched before cooling by pouring into 6 liters deionized water. The water slurry is acidified with 30% sulfuric acid and allowed to stand at room temperature overnight before filtering under reduced pressure and washing with several portions of boiling water to remove hydroquinone. The white residue is dried in a vacuum oven at 140° C. to a weight of 240 grams. It is then taken up in 4 liters boiling MEK, treated with decolorizing carbon and filtered through a filter acid, celite, to remove particulates and colored impurities. A total of 154 grams of a white produce is recovered from a series of filtrates. Analysis by gpc shows contamination by higher molecular weight species which are much less soluble in acetone than the desired product; thus, the produce is taken up in boiling acetone, filtered, and cooled to recover 135 grams (46% yield based on the dibromobutane). HPLC analysis showed >90% purity by peak area. Another crystallization from 3 liters boiling acetone yield 116 grams of white "mica-like" crystals (melting point 202° C.-204° C.) with greater than 96% purity by HPLC peak area for use in example 11 and 22. Both 1H and 13C NMR spectra are consistent with the proposed structure.

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