Isoprene → HCID 19864713, compound

Participants

Reaction Conditions

Reaction Steps

The diblock copolymer was prepared by a sequential addition of isoprene and and 2-vinylpyridine to secbutyllithium. Benzene (500 ml) was degassed as before with oxygen-free argon for 45 minutes. Secbutyllithium (0.8 ml of 1.3M, 1.04 mmoles) was syringed in followed by 63.13 g (0.93 moles) of isoprene. The solution was stirred at 35° C. for 15 minutes and 40° C. for 15 minutes. There was an exotherm to 45° C. The solution was stirred at 45° C. for 11/2 hours more. As before the magnetic stirring system was switched to a mechanical for more efficient stirring. An aliquot of polyisoprene was syringed out for determination of the molecular weight of the starting block and the solution cooled to 8° C. At this stage 2-vinylpyridine (27.06 g, 0.26 mole) was added. Chain transfer to 2-vinylpyridine was noticed by the dark red color. The solution was stirred at 8° C. for 30 minutes and was quenched with degassed methanol. As before, the copolymer was characterized by 1H NMR and GPC. These results are also summarized in Table 1.

Provenance & Evidence