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Updated: May 11, 2025

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
Published on: November 21, 2017
Polyoxometalate-Based Zinc-Organic Network as a Dual-Site Acid Catalyst for the Conversion of Polyethylene
Qian Liu1, Ya-Nan Sun1, Wei Yang1
1Hebei Technology Innovation Center for Energy Conversion Materials and Devices, Hebei Engineering Research Center of Thin Film Solar Cell Materials and Devices, National Demonstration Center for Experimental Chemistry Education, Testing and Analysis Center, College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang, Hebei 050024, P. R. China.
Abstract:
Chemical depolymerization and recycling of poly(ethylene terephthalate) (PET) constitute a sustainable, resource-efficient, and environmentally beneficial approach, which requires the development of efficient heterogeneous catalysts. Herein, polyoxometalate(POM)-based zinc-organic networks were synthesized as dual-site acid catalysts for the alcoholysis of PET into the value-added terephthalic acid (TPA) product, with formulas of [Zn2(μ2-Cl)(H2O)2(DTAB)3][PW12O40]·4H2O (1), [Zn2(DTAB)4][SiW12O40]·4H2O (2), and [Zn2(H2O)4(DTAB)2.5][HBW12O40]·8H2O (3) (DTAB = 1,4-di(4H-1,2,4-triazol-4-yl)benzene). Structural analysis showed that compounds 1 and 2 were composed of 2D Zn-ligand networks embedded POM clusters in an "egg-in-a-box" manner and that compound 3 consisted of a 3D POM-based host-guest framework constructed by {Zn2(H2O)4(N-N)3} units and [HBW12O40]4- clusters. Three compounds incorporate the Zn2+ Lewis acid centers and heteropolytungstate clusters, having the acid strength order compound 3 > compound 1 > compound 2. When employed as dual-site acid catalysts, the three compounds exhibited efficient catalytic performance for PET alcoholysis into TPA with >92% conversion rate and >94% selectivity of the TPA product, along with excellent recyclability and structural stability. This work offers a novel perspective for the development of POM-based heterogeneous catalysts in the upcycling of plastic waste.
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