Formation and degradation of 1,4-polybutadiene via metathesis: new results concerning cyclic oligomers

✍ Scribed by Emma Thorn-Csányi; Jens Hammer; Kai P. Pflug; J. Ulrich Zilles

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 373 KB
• Volume: 196
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1995.021960407

✦ Synopsis

The ring-opening metathesis polymerization (ROMP) of cyclic oligomers of butadiene (c,c-l,5-cyclooctadiene -COD -, f,t,f-l,5,9-cyclododecatriene -CDT -), the acyclic diene metathesis (ADMET) of 1,5-hexadiene and the intramolecular metathesis degradation of 1,4-polybutadiene (1,4-BR) were studied using stable tungsten and molybdenum carbene complexes as well as conventional metathesis catalysts. The determination of cyclic oligomers up to rings containing eight butadiene units shows, compared to the literature, different results regarding the distribution, concentration and cishrans ratio. Kinetic studies of the ROMP of COD and the intramolecular metathesis of 1,4-BR allow to explain the discrepancy. The ROMP product spectrum for the cyclobutene system known and accepted until now in the literature as ring-chain equilibrium is controlled kinetically and far apart from thermodynamic equilibrium according to our results.