State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China.
Angew Chem Int Ed Engl. 2023 May 2;62(19):e202301024. doi: 10.1002/anie.202301024. Epub 2023 Mar 31.
Polyethylene terephthalate (PET) hydrogenolysis can produce benzene, toluene, and xylene (BTX), where the selectivity control is challenging. We report a reaction pathway dictated by the Ru coordination environment by examining the binding geometries of adsorbates on differently coordinated Ru centers and their evolution during PET hydrogenolysis. A BTX yield of 77 % was obtained using a Ru/TiO with a Ru coordination number of ca. 5.0 where edge/corner sites are dominant, while more gas and saturated products were formed for Ru/TiO containing primarily terrace sites. Density functional theory and isotopic labelling revealed that under-coordinated Ru edge sites favor "upright" adsorption of aromatic adsorbates while well-coordinated Ru sites favor "flat-lying" adsorption, where the former mitigates ring hydrogenation and opening. This study demonstrates that reaction pathways can be directed through controlled reactant/intermediate binding via tuning of the Ru coordination environment for efficient conversion of PET to BTX.
聚对苯二甲酸乙二醇酯（PET）的氢解可以生成苯、甲苯和二甲苯（BTX），但选择性控制具有挑战性。通过考察不同配位 Ru 中心上吸附物的结合几何形状及其在 PET 氢解过程中的演化，我们报告了一种由 Ru 配位环境决定的反应途径。在 Ru 配位数约为 5.0 的 Ru/TiO 上，采用 Ru/TiO 催化剂，得到了 77%的 BTX 收率，其中边缘/角位占主导地位，而对于主要含有平台位的 Ru/TiO，形成了更多的气体和饱和产物。密度泛函理论和同位素标记表明，低配位 Ru 边缘位有利于芳香族吸附物的“直立”吸附，而配位良好的 Ru 位有利于“平躺”吸附，前者可以减轻环加氢和开环。本研究表明，通过控制 Ru 配位环境，可以通过控制反应物/中间体的结合来引导反应途径，从而实现 PET 向 BTX 的高效转化。
