合成了一种热稳定性良好、具有Brφnsted酸和Lewis酸双重酸性的金属锌功能化离子液体N-甲基丁基咪唑三溴化锌（[Bmim]ZnBr3）,并将其用于催化PET聚酯在乙二醇中的醇解反应。研究结果发现[Bmim]ZnBr3催化活性明显高于溴代N-甲基丁基咪唑（[Bmim]Br）和ZnBr2,反应温度和催化剂的浓度均是影响PET聚酯乙二醇醇解的重要因素。本文中合成的催化剂对常见的五种PET制品均有良好的催化降解作用,经FTIR和1H-NMR分析表明,降解产物是对苯二甲酸乙二醇酯（BHET）。推测的反应机理是：[Bmim]ZnBr3通过与聚酯分子形成环状过渡态完成催化历程。
A stable task-specific ionic liquid,namely 1-buty-3-methylimidazolium zinc bromine(ZnBr3) was synthesized by mixing 1-buty-3-methylimidazolium bromine Br and zinc bromide.The product has been used to catalyze PET degradation in ethylene glycol(glycolysis of PET),exhibiting the catalyst activity higher than individual Br and zinc bromide.Moreover,the glycolysis temperature and catalyst concentration were found two critical factors influencing the glycolysis of PET.Under the optimal reaction conditions,five common PET products were successfully degraded in ethylene glycol using the ZnBr3 as the catalyst.Confirmed by FT-IR and 1H NMR,the main product of the glycolysis was bis(2-hydroxyethyl) terephthalate(BHET) monomer..The result of Pyridine probe FT-IR show that the ZnBr3 has the dual acidity of Brnsted and Lewis,to which the higher catalytic activity for the glycolysis can be attributed.The mechanism of the catalyst is proposed that ZnBr3 plays a role during the formation of a cyclic compound during the glycolysis process.
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