Propylene Polymerization and Deactivation Processes with Isoselective {Cp/Flu} Zirconocene Catalysts
نویسندگان
چکیده
Industrially relevant single-site precatalysts used to produce isotactic polypropylene (iPP) include C2-symmetric {SBI} and C1-symmetric {Cp/Flu} complexes of group 4 metals. While the latter can iPPs with a higher degree isotacticity, they also suffer from poor productivity compared their counterparts. Several causes for this trend have been suggested—2,1-Regioinsertions are frequently pointed out, as suspected drive catalyst into dormant state. event does not seem significantly impact systems, influence these regioerror is poorly documented isoselective precatalysts. To address issue, new Ph2X(Cp)(Flu) (Ph2X = Ph2C, FluC, Ph2Si) proligands (2a–k) some corresponding dichlorozirconocenes (3a–h,k) were synthesized. These compounds characterized tested in homogeneous propylene polymerization at 60 °C amounts regioerrors resulting polymers examined by 13C NMR spectroscopy. A possible correlation between high number was investigated discussed. Furthermore, C-H activation process bulky nBu3C substituent upon 4c (the dimethylated analog 3c) B(C6F5)3 has evidenced NMR; DFT calculations support deactivation mechanism.
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ژورنال
عنوان ژورنال: Catalysts
سال: 2021
ISSN: ['2073-4344']
DOI: https://doi.org/10.3390/catal11080959