Catalytic conversion of polyoxymethylene with bio-derived substrates: kinetic modeling on solvent enhancement effect and experimental studies on reaction mechanism
Catalytic conversion of polyoxymethylene with bio-derived substrates: kinetic modeling on solvent enhancement effect and experimental studies on reaction mechanism
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DOI：
10.1016/j.ces.2023.118670
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发表时间：
2023-04-06
影响因子：
4.7
通讯作者：
Jin，Xin
中科院分区：
文献类型：
--
作者：
Du，Feng;Wang，Mengyu;Jin，Xin
废聚甲醛塑料催化转化为可再生和增值的化学品是绿色化学的一个有前途的领域。学术界和工业界以前的研究都集中在苛刻的操作温度和压力下的热解聚。在这项工作中，我们研究了详细的反应机理级联解聚和醚化聚甲醛与生物衍生的多元醇成有价值的含氧化合物。作为本工作的重点之一，我们提出并验证了一个涉及解聚和亲核攻击C单键O单键C键的两步机理。动力学模型、红外光谱和核磁共振谱揭示了溶剂增溶的机理：阳离子（Bi ~（3+））、阴离子（OTf ~-）和1，4-二氧六环的协同作用（1）诱导分子间氢键的形成，从而激活了多元醇分子中的C单键H键;（2）促进了对聚甲醛中碳正离子的亲核进攻。这项工作的结果将提供有用的基础数据，合理设计的工业过程，涉及原子有效的转换各种聚合物到增值产品。
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 Csingle bondOsingle bondC 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 Csingle bondOsingle bondH 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.