[C:1]([C:11]1[CH:16]=[CH:15][C:14]([OH:17])=[CH:13][CH:12]=1)([C:4]1[CH:9]=[CH:8][C:7]([OH:10])=[CH:6][CH:5]=1)([CH3:3])[CH3:2].[N:18]#CBr.C[C:22](C)=[O:23].C([N:27](CC)CC)C>O>[O-:17][C:14]#[N:18].[O-:23][C:22]#[N:27].[OH:10][C:7]1[CH:6]=[CH:5][C:4]([C:1]([C:11]2[CH:12]=[CH:13][C:14]([OH:17])=[CH:15][CH:16]=2)([CH3:3])[CH3:2])=[CH:9][CH:8]=14,4'-Isopropylidene diphenol (456.60 grams, 4.0 hydroxyl equivalents), cyanogen bromide (444.91 grams, 4.20 moles) and acetone (1100 milliliters) are added to a reactor and maintained under a nitrogen atmosphere with stirring. The stirred solution is cooled to -5° C., then triethylamine (406.82 grams, 4.02 moles) is added over a 60 minute period and so as to maintain the reaction temperature at -5° to -3° C. After completion of the triethylamine addition, the reactor is maintained at -5° to -3° C. for an additional 25 minutes followed by addition of the reactor contents to 1.5 gallons of deionized water. After 5 minutes, the water and product mixture is multiply extracted with three 500 milliliter volumes of methylene chloride. The combined methylene chloride extract is washed with 500 milliliters of 0.05 percent by weight aqueous hydrochloric acid followed by washing with 500 milliliters of deionized water, then drying over anhydrous sodium sulfate. The dry methylene chloride extract is filtered and solvent removed by rotary evaporation under vacuum for 60 minutes at 100° C. The bisphenol A dicyanate (545.8 grams) is recovered in 98.1 percent yield as a tan colored crystalline solid. Infrared spectrophotometric analysis of a film sample of the product confirmed the product structure (disappearance of phenolic hydroxyl, absorbance, appearance of cyanate absorbance).
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