| Popis: |
By the chromatographic method, under near to critical conditions, the distribution of functionality types was studied with hydroxyoligobutadienes synthesized with an initiator prepared by reaction of lithium with 2,4-hexadiene. It was shown that already at the stage of initiator synthesis, besides the required dilithium molecules, also mono- and trilithium compounds are formed in the reaction mixture, and in consequences of this the resulting oligomers contain mono-, bi- and trifunctional molecules. The number-average functionality of the oligomers can reach a value near to two, although the content of the bifunctional fraction does not exceed 60%. It was found that the solution of the initiator contains paramagnetic particles with a very narrow singlet EPR signal. Assumptions concerning possible mechanisms of functionality redistribution in the initiator solution are presented, including transmetallation processes and (or) reactions involving free-radical centres. |
