Allyl bromide → Isoprene butadiene

Participants

Reaction Conditions

Reaction Steps

In this experiment, an isoprene-butadiene copolymer rubber was prepared using an alcohol modified neodymium catalyst system. In this procedure, a one gallon (3.78 liter) reactor was charged with 1,214 grams of hexane containing 81.3 grams of butadiene and 558.43 grams of 1.23 molar diisobutylaluminum hydride (DIBAH) in hexane, (i.e., 25% weight percent DIBAH). The reactor was maintained at 20° C. by cooling. N-butanol (11.16 grams) was added with stirring. After stirring for thirty minutes, 107.5 grams of 10.1% neodymium solution (neodymium neodecanoate) diluted with 160 grams of dry hexane, was charged to the reactor. The-solution was stirred for another thirty minutes after which time 18.2 grams of allyl bromide was added. The cooling was stopped and the solution was allowed to warm up. A delayed exothermic reaction was noted. After twenty minutes, bring the solution temperatures to about 10° C. above ambient temperature. When the temperature ultimately dropped, the catalyst solution was aged by heating at 65° C. for ninety minutes. The catalyst prepared had a butanol-DIBAH!Nd-allyl bromide-butadiene molar ratio of 2-13!-1-2-20, respectively, and a concentration of 0.025 molarity with respect to the neodymium.

Provenance & Evidence