Isopropanol → 4,4'-Diglycidyloxy-alpha-methylstilbene

Participants

Reaction Conditions

Reaction Steps

4,4'-Dihydroxy-alpha-methylstilbene (452.5 grams, 4.0 hydroxyl equivalents) from A above, epichlorohydrin (1850.6 grams, 20.0 moles), deionized water (160.9 grams, 8.0 percent by weight of the epichlorohydrin used) and isopropanol (996.5 grams, 35 percent by weight of the epichlorohydrin used) are added to a reactor and heated to 50° C. with stirring under a nitrogen atmosphere. Once the 50° C. temperature is achieved, sodium hydroxide (144.0 grams, 3.60 moles) dissolved in deionized water (576.0 grams) is added dropwise to the reactor over a 45 minute period and so as to maintain the reaction temperature between 50° and 61° C. Ten minutes after completion of the aqueous sodium hydroxide addition, the stirring is stopped and the aqueous layer which separates from the reaction mixture is pipetted off and discarded. Stirring is resumed and after a total of 20 minutes following the completion of the initial aqueous sodium hydroxide addition, a second solution of aqueous sodium hydroxide (64.0 grams, 1.60 mole) dissolved in deionized water (256.0 grams) is added to the reactor over a 20 minute period with maintenance of the reaction temperature between 50° and 51° C. Fifteen minutes after completion of the aqueous sodium hydroxide, the recovered reaction mixture is added to a separatory funnel and washed with warm (60° to 70° C.) deionized water (1200 milliliters). The separated organic layer is washed a second time (1200 milliliters of warm deionized water), recovered and then rotary evaporated under vacuum using final conditions of 150° C. and one mm Hg vacuum for 2 hours. After removal from the rotary evaporator, the molten epoxy resin is vacuum filtered through a heated (175° C.) medium fritted glass funnel, then poured into an aluminum foil tray to solidify. The 4,4'-diglycidyloxy-alpha-methylstilbene is recovered (645.4 grams) as a crystalline white solid. Titration of portions of the diglycidyl ether product reveals an epoxide equivalent weight (EEW) of 181.15. Analysis of a portion of the diglycidyl ether product via microscopy under crosspolarized light is completed at 70× magnification using a microscope equipped with a programmable hot stage using a heating rate of 10° C. per minute and a range of 30° to 150° C., immediately followed by cooling. Isotropization is observed at 131° C., liquid crystallinity occurs at 92° C. and crystallization occurs at 55° C. The diglycidyl ether is a monotropic liquid crystal with a nematic texture.

Provenance & Evidence