1,3-Butadiene → HCID 20278179, compound

Participants

Reaction Conditions

Reaction Steps

One thousand milliliters of purified pentane and 100 mL of tetrahydrofuran distilled over benzophenone ketyl were introduced under a nitrogen atmosphere into a two quart glass bowled stirred pressure reactor. The reactor was equipped with an air driven stirrer, a pressure gauge, a thermometer well, a heat exchange coil, a top surface inlet valve, a dip tube feeder with a valve, a syringe injection port containing a Viton rubber gasket, and a blow-out disk (200 psi). One milliliter of a 0.1M dipyridyl in cyclohexane solution was injected into the reactor along with 33.4 mL (30.0 g, 0.254 mol) of p-methylstyrene (p-MS) that had been passed through alumina. Butadiene (120 g, 2.22 mol) was then pressured into a 300 mL Hoke bomb. The bomb was fitted onto the reactor and the contents were pressured into it. The solution was heated to 35° C. then titrated by slow addition of 1.6M n-butyllithium until a red color persisted. The catalyst, 4.7 mL of n-butyllithium, was added. Polymerization of the butadiene and p-MS was continued at 25°-30° C. for 3.6 hours. The living anion was then quenched by the addition of 0.5 mL of 4-hydroxy-4-methyl-2-pentanone. A portion of the polymer was concentrated under reduced pressure. Gel permeation chromatography of the sample showed the polymer to have a number average molecular weight (Mn) and a weight average molecular weight (Mw) of 2.00×104 and 2.10×104, respectively, and a polydispersity index of 1.05.

Provenance & Evidence