Example 15
A 100 mL Schlenk flask containing a ground glass stopcock, equipped with a stirring bar and a rubber septum, was flame-dried under vacuum (7 mm Hg). Upon cooling to room temperature, the reaction vessel was weighed (sans an internal atmosphere), charged with sulfuryl fluoride gas (SO2F2) and finally re-weighed to determine the quantity of SO2F2 (752 mg, 7.37 mmol). ((Propane-2,2-diylbis(4,1-phenylene))bis(oxy))bis(tert-butyldimethylsiane) (3.30 g, 7.22 mmol) dissolved in 7 mL anhydrous DMF and 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP; 368 μL, 101 mg, 0.368 mmol) as a 1 M solution in hexanes were then added to the reaction vessel in that order and the resulting mixture was stirred at room temperature for 20 min, as a closed (to the atmosphere) system. The reaction vessel was then placed in a 150° C. oil bath and shortly thereafter the evolution of low boiling solvents (presumably hexanes and tert-butylfluorodimethylsilane (TBSF)) was visible on walls of the reaction vessel. The reaction progressed as a closed system at 150° C. for 30 min at which point the stopcock was opened thereby releasing gaseous hexanes and TBSF, heating was then continued for an additional 2 h as an open system. The reaction mixture was then removed from the oil bath as a viscous, slightly yellow clear liquid and allowed to cool to room temperature. Direct addition of the reaction mixture to 200 mL MeOH resulted in precipitation of BPA-polysulfate as a white fibrous solid. Drying under vacuum at 80° C. for 3 h yielded 1.966 g (94%) with Mn of 95,000 Da based on polystyrene standards.
