Catalytic conversion of polyoxymethylene with bio-derived substrates: kinetic modeling on solvent enhancement effect and experimental studies on reaction mechanism

•Proposed and validated a two-step mechanism involving depolymerization and nucleophilic attack C-O-C bond.•Kinetic modelling reveals the pseudo-1st order mechanism for transformation of polyoxymethylene.•IR and NMR spectra reveal synergism of Bi3+ and OTf- through activating C-OH bond.•Transforming...

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Bibliographic Details
Published in:Chemical engineering science 2023-06, Vol.274, p.118670, Article 118670
Main Authors: Du, Feng, Wang, Mengyu, Wang, Libin, Li, Yushan, Wang, Yuangao, Deng, Wenan, Yan, Wenjuan, Jin, Xin
Format: Article
Language:English
Subjects:
Biomass
Catalysis
Mechanism
Polyoxymethylene
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Summary:•Proposed and validated a two-step mechanism involving depolymerization and nucleophilic attack C-O-C bond.•Kinetic modelling reveals the pseudo-1st order mechanism for transformation of polyoxymethylene.•IR and NMR spectra reveal synergism of Bi3+ and OTf- through activating C-OH bond.•Transforming polyoxymethylene with various bio-substrates leads to promising molecular and economic cycling. Catalytic conversion of waste polyoxymethylene plastics to renewable and value-added chemicals represents a promising area in green chemistry. Previous studies in both academia and industry have focused on thermal depolymerization under harsh operating temperature and pressure. In this work, we have investigated the detailed reaction mechanism for cascade depolymerization and etherification of polyoxymethylene with bio-derived polyols into valuable oxygenates. As one of the highlights in this work, we proposed and validated a two-step mechanism involving depolymerization and nucleophilic attack COC bond. Kinetic modeling, IR and NMR spectra revealed mechanistic information for solvent-enhancement: the synergism of cation (Bi3+), anion (OTf-) and 1,4-dioxane (1) induces formation of intermolecular H bonding thus activating COH bond in polyol molecules, and (2) facilitates nucleophilic attack on carbocation in polyoxymethylene. The outcome of this work will provide useful fundamental data for rational design of industrial processes involving atomic efficient conversion of various polymers into value-added products.
ISSN:0009-2509
1873-4405
DOI:10.1016/j.ces.2023.118670