Cis-Specific Living Polymerization of 1,3-Butadiene Catalyzed by Alkyl and Alkylsilyl Substituted Cyclopentadienyltitanium Trichlorides with MAO

• Published in: Macromolecules Vol. 33; no. 8; pp. 2796 - 2800
• Main Authors: Miyazawa, Akira, Kase, Toshio, Soga, Kazuo
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 18.04.2000
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts; Substituent effect; Titanium complex; Living polymer; Temperature effect; Complex catalyst polymerization; Complex catalyst; Experimental study; Solution polymerization; Cis stereoisomer; Butadiene polymer; Stereospecificity; Chloro complex; Hapto complex; Aluminium Organic compounds; Kinetics; Rate constant; Stereospecific polymerization; Catalyst activity; Reaction propagation
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma991489n

Cis-specific living polymerizations of 1,3-butadiene (BD) catalyzed by the catalyst system composed of C5H4RTiCl3 (4a, R = H; 4b, R = n-butyl; 4c, R = isopropyl; 4d, R = tert-butyl; 4e, R = trimethylsilyl) with methylaluminoxane (MAO) to give polyBDs with narrow molar mass distribution and high cis content are described. Polybutadienes (polyBDs) prepared by the catalyst at −25 °C are monodispersed (M w / M n = 1.04−1.05) in all cases. From the comparison with propagation rate constants (k p), the order of polymerization activity was as follows:  4d > 4e > 4c > 4b = 4a. The microstructures of polyBDs were all dominated by the cis configuration. The complex 4d having bulky tert-butyl group showed higher cis specicficity. Both k ps and cis specificity in the polymerization of BD were strongly affected by the substituents introduced on the cyclopentadienyl ring.