Copolymerization of Ethylene and Vinyl Fluoride by Self-Assembled Multinuclear Palladium Catalysts

• Main Authors: Qian Liu, Richard F. Jordan
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Polymers
• Subjects: multinuclear catalyst; vinyl fluoride; copolymerization; fluorinated polyethylene
• Online Access: https://www.mdpi.com/2073-4360/12/7/1609

The self-assembled multinuclear Pd^II complexes {(Li-OPO^OMe2)PdMe(4-5-nonyl-pyridine)}₄Li₂Cl₂ (<b>C</b>, Li-OPO^OMe2 = PPh(2-SO₃Li-4,5-(OMe)₂-Ph)(2-SO₃⁻-4,5-(OMe)₂-Me-Ph)), {(Zn-OP-P-SO)PdMe(L)}₄ (<b>D</b>, L = pyridine or 4-<i>^t</i>Bu-pyridine, [OP-P-SO]³⁻ = P(4-^tBu-Ph)(2-PO₃²⁻-5-Me-Ph)(2-SO₃⁻-5-Me-Ph)), and {(Zn-OP-P-SO)PdMe(pyridine)}₃ (<b>E</b>) copolymerize ethylene and vinyl fluoride (VF) to linear copolymers. VF is incorporated at levels of 0.1–2.5 mol% primarily as in-chain -CH₂CHFCH₂- units. The molecular weight distributions of the copolymers produced by <b>D</b> and <b>E</b> are generally narrower than for catalyst <b>C</b>, which suggests that the Zn-phosphonate cores of <b>D</b> and <b>E</b> are more stable than the Li-sulfonate-chloride core of <b>C</b> under copolymerization conditions. The ethylene/VF copolymerization activities of <b>C</b>–<b>E</b> are over 100 times lower and the copolymer molecular weights (MWs) are reduced compared to the results for ethylene homopolymerization by these catalysts.