CO<sub>2</sub>Fixation and PCHC Depolymerization by a Dinuclear<i>β</i>‐Diketiminato Zinc Complex

Liao, Xi; He, Julong; Zhang, Yuetao

doi:10.1002/asia.202201076

Cited by 3 publications

(4 citation statements)

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“…Under comparable conditions at 140 °C, the Cr(III) catalyst system reached only 5% PCHC conversion. Liao and co-workers reported a Zn(II) catalyst, formed by the partial hydrolysis of (BDI-ZnMe 2 ) (BDI = β-diketiminato), which showed a TOF of 2.5 h –1 , at 150 °C (catalyst:PCHC 1:50). , Overall, compared to the other known polycarbonate chemical recycling catalysts, these dinuclear catalysts benefit from being single component enabling them to be applied at lower loadings, operate at low temperatures, and show field-leading activity values.…”

Section: Discussionmentioning

confidence: 99%

“…30 PCHC depolymerization using a decomposed di-Zn(II) polymerization catalyst was also reported. 32,33 Solution phase chemical recycling has a number of potential limitations, including the need to isolate the product from the solvent. To address this issue, solid-state chemical recycling processes were investigated.…”

Section: ■ Introductionmentioning

confidence: 99%

“…However, other catalysts showing high activity in CHO/CO 2 ROCOP were completely inactive in chemical recycling . PCHC depolymerization using a decomposed di-Zn(II) polymerization catalyst was also reported. , …”

Section: Introductionmentioning

confidence: 99%

“… 30 PCHC depolymerization using a decomposed di-Zn(II) polymerization catalyst was also reported. 32 , 33 …”

Section: Introductionmentioning

confidence: 99%

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Evaluating Heterodinuclear Mg(II)M(II) (M = Mn, Fe, Ni, Cu, and Zn) Catalysts for the Chemical Recycling of Poly(cyclohexene carbonate)

Smith,

McGuire,

Buchard

et al. 2023

ACS Catal.

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Polymer chemical recycling to monomers (CRM) is important to help achieve a circular plastic economy, but the “rules” governing catalyst design for such processes remain unclear. Here, carbon dioxide-derived polycarbonates undergo CRM to produce epoxides and carbon dioxide. A series of dinuclear catalysts, Mg(II)M(II) where M(II) = Mg, Mn, Fe, Co, Ni, Cu, and Zn, are compared for poly(cyclohexene carbonate) depolymerizations. The recycling is conducted in the solid state, at 140 °C monitored using thermal gravimetric analyses, or performed at larger-scale using laboratory glassware. The most active catalysts are, in order of decreasing rate, Mg(II)Co(II), Mg(II)Ni(II), and Mg(II)Zn(II), with the highest activity reaching 8100 h –1 and with >99% selectivity for cyclohexene oxide. Both the activity and selectivity values are the highest yet reported in this field, and the catalysts operate at low loadings and moderate temperatures (from 1:300 to 1:5000, 140 °C). For the best heterodinuclear catalysts, the depolymerization kinetics and activation barriers are determined. The rates in both reverse depolymerization and forward CHO/CO 2 polymerization catalysis show broadly similar trends, but the processes feature different intermediates; forward polymerization depends upon a metal–carbonate intermediate, while reverse depolymerization depends upon a metal-alkoxide intermediate. These dinuclear catalysts are attractive for the chemical recycling of carbon dioxide-derived plastics and should be prioritized for recycling of other oxygenated polymers and copolymers, including polyesters and polyethers. This work provides insights into the factors controlling depolymerization catalysis and steers future recycling catalyst design toward exploitation of lightweight and abundant s-block metals, such as Mg(II).

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Section: Discussionmentioning

confidence: 99%