Acetic Acid → Isoprene butadiene

Participants

Reaction Steps

A 5-gallon reactor was charged with 10.1 L of purified pentane under an inert atmosphere. To the reactor was added 632.5 g (9.29 mol) of purified isoprene, 62.2 ml of anhydrous tetrahydrofuran, and 10.0 ml of 2,2'-dipyridyl solution (0.1M) via a Hoke bomb. The reactor contents were heated to 50°-55° C. and titrated to a yellow-brown endpoint color with 1.6M n-butyllithium. The catalyst 1.6M n-butyllithium (263.5 ml, 0.421 mole) was then added to the reactor using a Hoke bomb. The polymerization reaction temperature was maintained between 50°-55° C. for 1 hour then cooled to 45°-50° C. At this time, 3584 g (66.4 mol) of freshly distilled butadiene was added. The polymerization continued for 0.5 hours, after which time 25.3 g (0.421 mol) of acetic acid was added. The molecular weight (Mn) was found to be approximately 10,000. An infrared analysis (FTIR) showed the butadiene microstructure to contain 55% 1,2- and 45% 1,4-microstructure.

Provenance & Evidence