Kinetic study of isospecific active sites formed by various alkylaluminiums on MgCl2-supported Ziegler catalyst at the initial stage of propene polymerization

✍ Scribed by Hideharu Mori; Hiromitsu Iguchi; Kouichi Hasebe; Minoru Terano

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 342 KB
• Volume: 198
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1997.021980426

✦ Synopsis

Abstract

The effect of various kinds of alkylaluminium on the kinetic parameters of the initial stage of propene polymerization with MgCl~2~‐supported Ziegler catalyst was studied by the stopped‐flow polymerization method. The active sites concentration ([C^*^]) decreased drastically with the increase of bulkiness of the alkyl group of the aluminium compound, while the change of the propagation rate constant (k~p~) was rather small and proportional to the meso pentad fraction of the resulting polypropene. The kinetic parameters, k~p~(insol) and [C^*^(insol)], were calculated from the yield and number‐average molecular weight of the boiling heptane insoluble fraction. The values of k~p~ (insol) were almost constant, while those of k~p~ depended on the ratio [C^*^(insol)]/[C^*^(total)]. The results obtained in this study suggest that isospecific active sites produced by various alkylaluminiums are essentially the same, but the amounts of the active sites formed with a variety of alkylaluminiums are different.