Post-functionalization of narrowly dispersed PE waxes generated using tuned N, N, N′-cobalt ethylene polymerization catalysts substituted with ortho-cycloalkyl groups. (20th January 2021)

• Record Type: Journal Article
• Authors: Suo, Hongyi; Oleynik, Irina V.; Oleynik, Ivan I.; Solan, Gregory A.; Ma, Yanping; Liang, Tongling; Sun, Wen-Hua
• Is Part Of: Polymer. Volume 213(2021)
• Publication Date: 2021-01-20
• Subjects: bis(arylimino)trihydroquinolyl-cobalt precatalyst -- Ethylene polymerization -- Polyethylene waxes -- Catalyst thermostability -- Post-functionalization; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2020.123294
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Six structurally related bis(arylimino)trihydroquinolyl-cobalt (II) chloride complexes [2-(ArNCCH3 )-8-(ArN)-5, 6, 7-C9 H8 N]CoCl2 (Ar = 2-(C5 H9 )-6-MeC6 H3 Co1, 2-(C6 H11 )-6-MeC6 H3 Co2, 2-(C8 H15 )-6-MeC6 H3 Co3, 2-(C5 H9 )-4, 6-Me2 C6 H2 Co4, 2-(C6 H11 )-4, 6-Me2 C6 H2 Co5, 2-(C8 H15 )-4, 6-Me2 C6 H2 Co6 ), distinguishable by the ring size of the ortho -cycloalkyl substituent and type of para -R group, have been synthesized and characterized. A distorted square pyramidal geometry is a feature of the molecular structure of Co4 with the two ortho -cyclopentyl groups located on neighboring N -aryl groups trans -configured. Compounds Co1 – Co6, on activation with methylaluminoxane (MAO) or modified MAO (MMAO), proved highly productive catalysts for ethylene polymerization at 60 °C [up to 17.1 × 10 6 g (PE) mol −1 (Co) h −1 for cyclopentyl-containing Co4 /MAO]; even at 90 °C significant activity was attainable (up to 6.75 × 10 6 g (PE) mol −1 (Co) h −1 ). Strictly linear polyethylene waxes of low molecular weight ( ca. 1.50 kg mol −1 ), narrow dispersity ( M w / M n range: 1.1–2.4) and incorporating high levels of vinyl end-groups were generated. Post-functionalization of these PE waxes by epoxidation, thiol-ene addition and cross-olefin metathesis to form e-PE, PE-S-CH2 CH2 NH2 ·HCl and PE-MMA, respectively, has been demonstrated. For comparative purposes, [2-(ArNCCH3 )-8-ArN-5, 6, 7-C9 H8 N]CoCl2 (Ar = 2, 4, 6-Me3 C6 H2 Co o -Me, 2-(Ph2 CH)-4, 6-Me2 C6 H2 Co o -CHPh2 ) have also been prepared and evaluated as polymerization catalysts. Graphical abstract: Image 1 Highlights: Cobalt ethylene polymerization catalysts capable of running at temperatures up to 90 °C. ortho -Cycloalkyl ring-size variation allows fine control of catalytic performance. PE waxes with narrow dispersities and high levels of vinyl end-groups are produced. Amenability of the PE waxes to post-functionalization by epoxidation, thiol-ene addition and cross-olefin metathesis has been demonstrated. Ready synthesis of catalysts and characteristic vinyl-polyethylenes offer industrial potential.