Bis(2-hydroxyethyl terephthalate) (BHET) obtained by poly(ethylene terephthalate) (PET) catalytic glycolysis often has a slight color, which results in the subsequent preparation of repolymerized PET (rPET) with a darker color. The darker rPET is unable to be utilized in a high value. In order to obtain BHET with good chroma, a series of mesoporous catalysts were proposed and synthesized. Compared with traditional catalysts, the developed catalysts have obvious advantages to obtain BHET with a good chroma. The chromaticity values of BHET obtained through ZnO/SBA-15 catalyst are 96.64, 0.16 and 1.39 (L, a and b), and the chromaticity values of rPET after polymerization are 93.69, 0.86 and 1.31. The 5% ZnO/SBA-15 catalyst displayed prominent capabilities to degrade PET into BHET. The key factors influencing the reaction were further studied. Under the conditions of reaction temperature 197 °C, reaction time 1 h, mass ratio of Cat./PET 5% and mass ratio of ethylene glycol (EG)/PET 4:1, the catalytic efficiency reached the optimal one where conversion of PET is 100% and yield of BHET is 91.0%. The PET degradation kinetic was studied and conforms to the first order reaction kinetics. The reaction mechanism was deduced by in situ infrared reaction and theoretical calculation. The mechanism of ester bond breaking catalyzed by ZnO/SBA-15 was proposed. Mesoporous catalyst still has excellent catalytic activity through multiple recycling.

聚对苯二甲酸乙二醇酯 (PET) 催化糖酵解得到的双 (2-羟乙基对苯二甲酸酯) (BHET) 通常有轻微的颜色，这导致后续制备的重聚 PET (rPET) 颜色较深。颜色较深的 rPET 无法以高价值使用。为了获得具有良好色度的BHET，提出并合成了一系列介孔催化剂。与传统催化剂相比，所开发的催化剂在获得具有良好色度的BHET方面具有明显的优势。通过ZnO/SBA-15催化剂得到的BHET色度值为96.64、0.16和1.39（L、a和b），聚合后rPET的色度值为93.69、0.86和1.31。5% ZnO/SBA-15 催化剂显示出显着的将 PET 降解为 BHET 的能力。进一步研究了影响反应的关键因素。在反应温度197℃、反应时间1h、Cat./PET质量比5%、乙二醇(EG)/PET质量比4:1的条件下，催化效率达到了PET转化率的最佳值为 100%，BHET 的产率为 91.0%。研究了 PET 降解动力学，符合一级反应动力学。通过原位红外反应和理论计算推导出反应机理。提出了ZnO/SBA-15催化酯键断裂的机理。介孔催化剂经过多次循环利用仍具有优良的催化活性。研究了 PET 降解动力学，符合一级反应动力学。通过原位红外反应和理论计算推导出反应机理。提出了ZnO/SBA-15催化酯键断裂的机理。介孔催化剂经过多次循环利用仍具有优良的催化活性。研究了 PET 降解动力学，符合一级反应动力学。通过原位红外反应和理论计算推导出反应机理。提出了ZnO/SBA-15催化酯键断裂的机理。介孔催化剂经过多次循环利用仍具有优良的催化活性。