Metal-Oxide-Doped Silica Nanoparticles for the Catalytic Glycolysis of Polyethylene Terephthalate
Metal-Oxide-Doped Silica Nanoparticles for the Catalytic Glycolysis of Polyethylene Terephthalate
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DOI：
10.1166/jnn.2011.3201
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发表时间：
2011-01-01
影响因子：
--
通讯作者：
Kim, Do Hyun
中科院分区：
文献类型：
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作者：
Imran, Muhammad;Lee, Kyoung G.;Kim, Do Hyun
在浸渍在不同形式的二氧化硅载体[二氧化硅纳米颗粒（SNP）或二氧化硅微粒（SMPs）]上的金属氧化物作为糖酵解催化剂的存在下，使用过量的乙二醇（EG）将聚对苯二甲酸乙二醇酯（PET）解聚为单体对苯二甲酸双（2-羟乙基）酯（BHET）。反应在300 ℃和1.1 MPa下进行，EG与PET的摩尔比为11：1，催化剂与PET的重量比为1.0%，反应时间为40-80 min。在四种制备的催化剂（Mn 3 O 4/SNPs 5，ZnO/SNPs，Mn 3 O 4/SMPs和ZnO/SMPs）中，Mn 3 O 4/SNPs纳米复合材料具有最高的单体产率（>90%）。这种高产率可以通过纳米复合催化剂的高表面积、无定形和多孔结构以及许多活性位点的存在来解释。BHET产率随时间增加，并达到最高水平，其中BHET和其二聚体之间建立平衡。通过SEM、TEM、BET比表面积和XRD对催化剂进行了表征，通过HPLC和FT-IR对单体BHET进行了表征。以Mn 3 O 4/SNPs纳米复合材料为糖酵解催化剂，在较短的反应时间内产生最大的BHET。
Polyethylene terephthalate (PET) was depolymerized to monomer bis(2-hydroxyethyl) terephthalate (BHET) using excess ethylene glycol (EG) in the presence of metal oxides that were impregnated on different forms of silica support [silica nanoparticles (SNPs) or silica microparticles (SMPs)] as glycolysis catalysts. The reactions were carried out at 300 degrees C and 1.1 MPa at an EG-to-PET molar ratio of 11:1 and a catalyst-to-PET-weight ratio of 1.0% for 40-80 min. Among the four prepared catalysts (Mn3O4/SNP5, ZnO/SNPs, Mn3O4/SMPs, and ZnO/SMPs), the Mn3O4/SNPs nanocomposite had the highest monomer yield (>90%). This high yield may be explained by the high surface area, amorphous and porous structure, and existence of numerous active sites on the nanocomposite catalyst. The BHET yield increased with time and reached the highest level where equilibrium was established between BHET and its dimer. The catalysts were characterized by their SEM, TEM, and BET surface areas, and via XRD, whereas the monomer BHET was characterized by HPLC and FT-IR. The glycolysis with the Mn3O4/SNPs nanocomposite as the glycolysis catalyst produced a maximum BHET in a short reaction time.