4, 4′-Dimethoxybenzhydryl substituent augments performance of bis(imino)pyridine cobalt-based catalysts in ethylene polymerization. Issue 25 (24th May 2022)

• Record Type: Journal Article
• Authors: Yuan, Shi-Fang; Wang, Luyao; Yan, Yi; Liu, Tian; Flisak, Zygmunt; Ma, Yanping; Sun, Wen-Hua
• Is Part Of: RSC advances. Volume 12:Issue 25(2022)
• Page Start: 15741
• Page End: 15750
• Publication Date: 2022-05-24
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d2ra01547a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Employing ligands with 4, 4′-dimethoxybenzhydryl groups, the cobalt precatalysts display high activities toward ethylene polymerization and produce highly linear polyethylenes, the high density polyethylene (HDPE). Abstract : A series of cobalt complexes with bis(imino)pyridine derivatives featuring unsymmetrical substitution with bulky groups has been synthesized and characterized. The molecular structures of two representatives have been determined by the single-crystal X-ray diffraction study, revealing distorted tetrahedral geometry with different degrees of steric hindrance imparted by the two inequivalent aryl groups attached to the imine nitrogen atoms. On activation with either MAO or MMAO, these complexes display high activity toward ethylene polymerization, reaching 8.71 × 10 6 g of PE (mol of Co) −1 h −1 at 60 °C and produce polyethylene of high molecular weight ( M w = 5.27 × 10 5 g mol −1 ) and low dispersity. The presence of the methoxy-substituent noticeably enhances the activity of the cobalt catalyst and increases the molecular weight of the resultant polyethylene.