Allyl bromide → Isoprene butadiene

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In this experiment, an isoprene-butadiene copolymer was synthesized using an alcohol modified neodymium catalyst system modified with 1,4-butanediol. In this procedure, a one gallon (3.78 liter) reactor was charged with 1,093 grams of hexane containing 81.9 grams of butadiene and 663 grams of 1.2 molar diisobutylaluminum hydride (DIBAH) in hexane (i.e., 25% weight percent DIBAH). To this solution was then added 6.78 grams of 1,4-butanediol with stirring and with temperatures maintained at 20° C. The suspension of the butanediol gradually dissolved upon reacting with the DIBAH. After one hour of stirring, 105.4 grams of a 10.3% neodymium solution (neodymium neodecanoate), diluted with 165 grams of hexane, was added to the reactor. The solution was stirred for another thirty minutes after which time 19.1 grams of allyl bromide was added. The cooling was stopped and the mixture allowed to warm up to ambient (and above) temperature. After the exotherm subsided, the catalyst solution was aged by heating at 65° C. for ninety minutes. The catalyst prepared had a [butanediol-DIBAH]-ND-allyl bromide-butadiene molar component ratio of [1-16]-1-2-20, respectively, and a concentration of 0.025 molarity with respect to the neodymium. The aged catalyst was then cooled and stored in a dry container under nitrogen.

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