Zur Taktizität von Poly(α-methylstyrol), 6. Zum stereoregulierenden Mechanismus der Polyreaktion des α-Methylstyrols mit Butyllithium in Tetrahydrofuran
✍ Scribed by Wicke, Reinhard ;Elgert, Karl-Friedrich
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1977
- Weight
- 674 KB
- Volume
- 178
- Category
- Article
- ISSN
- 0025-116X
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Some models of the stereoregulating mechanism of the polymerisation of α‐methylstyrene with butyllithium in tetrahydrofuran are discussed. A mechanism is proposed, in which the depolymerisation of the polymer chain and an isomerisation reaction of the active site change the tacticity generated by each propagation step. The isomerisation reaction is interpreted as a dissociation of the active lithiumorganic compound occurring with racemisation. The quantitative calculation of the tacticity based on the mechanism without depolymerisation using kinetic data agrees well with the experimental dependence of the tacticity on reaction temperature and initial monomer concentration. The activation parameters of the isomerisation reaction used in this treatment are (index r = racemic, m = meso):