Glycolysis of poly(ethylene terephthalate) waste catalyzed by mixed Lewis acidic ionic liquids
Glycolysis of poly(ethylene terephthalate) waste catalyzed by mixed Lewis acidic ionic liquids
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DOI：
10.1007/s10973-020-10331-8
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发表时间：
2020-10-29
影响因子：
4.4
通讯作者：
Fu Chaonan
中科院分区：
文献类型：
--
作者：
Chen Shuangjun;Shi Weihe;Fu Chaonan
聚对苯二甲酸乙二醇酯(PET)材料的广泛使用引起了人们对其废弃物的环境关注。合成了不同的1-己基-3-甲基咪唑(Hmim)卤酸盐(Hmim)，包括[Hmim]ZnCl3、[Hmim]CoCl3、[Hmim]FeCl4和[Hmim]CuCl3，作为Lewis酸性离子液体(LAIL)催化剂，用于在过量乙二醇(EG)中降解PET。采用单独或混合LaIL催化剂对产物对苯二甲酸二羟乙酯(BHET)进行了红外光谱、核磁共振氢谱和差示扫描量热法等表征。从PET转化率和BHET产物的产率来看，[Hmim]ZnCl3和[Hmim]CoCl3的混合络合物具有协同效应。用等摩尔的[Hmim]ZnCl3和[Hmim]CoCl3混合物催化原聚酯废料中87.1%的BHET，高于任何单独的IL卤化物。分别用[Hmim]Cl3和[Hmim]CoCl3催化剂去除不同反应时间的BHET产物后的过滤残留物进行了H-1-核磁共振表征。过滤残渣中CoO-CH2的亚甲基质子(Delta=4.30ppm)和苯环上的芳香族质子(Delta=8.12ppm)的面积比表明，由于[Hmim]ZnCl3在断链阶段具有较高的催化活性，将产生更多的副产物。糖酵解的协同作用来源于[Hmim]氯化锌的高活性和[Hmim]CoCl3的高选择性之间的平衡。
Widely used poly(ethylene terephthalate) (PET) material induces environmental concern on its wastes. In this paper, different 1-hexyl-3-methylimidazolium (Hmim) halometallates, including [Hmim]ZnCl3, [Hmim]CoCl3, [Hmim]FeCl4 and [Hmim]CuCl3, are synthesized as Lewis acidic ionic liquids (LAIL) catalysts for PET degradation in excess ethylene glycol (EG). By using individual or mixed LAIL catalysts, product bis(hydroxyethyl) terephthalate (BHET) is characterized by FT-IR, H-1-NMR and DSC et al. From the PET conversion and yield of BHET product, a synergistic effect is found in mixed [Hmim]ZnCl3 and [Hmim]CoCl3 complexes. 87.1% BHET from original PET wastes catalyzed by equimolar [Hmim]ZnCl3 and [Hmim]CoCl3 mixture is higher than any individual IL halometallate. The filter residues after removing the BHET products with different reacting time using [Hmim]ZnCl3 and [Hmim]CoCl3 as catalyst, respectively, are characterized by H-1-NMR. The area ratio of the methylene protons of COO-CH2 (delta = 4.30 ppm) and the aromatic protons of the benzene ring (delta = 8.12 ppm) of filter residues suggests that more by-products will be produced by [Hmim]ZnCl3 because of its relatively higher catalytic activity in the chain scission stage. The glycolysis synergy comes from the balance between high reactivity of [Hmim]ZnCl3 and high selectivity of [Hmim]CoCl3.