Han Wanying, Lin Longfei, Cen Ziyu, Ke Yubin, Xu Qian, Zhu Junfa, Mei Xuelei, Xia Zhanghui, Zheng Xinrui, Wang Yaqin, Liu Yani, He Mingyuan, Wu Haihong, Han Buxing
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, State Key Laboratory of Petroleum Molecular & Process Engineering, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China.
Institute of Eco-Chongming, 20 Cuiniao Road, Chenjia Town, Chongming District, Shanghai, 202162, China.
Angew Chem Int Ed Engl. 2025 Feb 3;64(6):e202417923. doi: 10.1002/anie.202417923. Epub 2024 Nov 22.
Branched alkanes, which enhance the octane number of gasoline, can be produced from waste polyethylene. However, achieving highly selective production of branched alkanes presents a significant challenge in the upcycling of waste polyethylene. Here, we report a one-pot process to convert polyethylene into gasoline-range hydrocarbons (C-C) with yield of 73.3 % over SO/ZrO-AlO catalyst at 280 °C. The proportion of branched alkanes reaches 90.1 % within the C-C fraction. Incorporation of sulfate group endows the catalyst with strong Lewis acid sites and weak and moderate Brønsted acid sites. In situ X-ray absorption, in situ infrared spectroscopy, in situ small angle neutron scattering, and DFT calculations reveal that polyethylene activation occurs through the synergy between sulfate groups and strong Lewis acid sites (Zr sites). The weak and moderate Brønsted acid sites preferentially catalyze the isomerization and type A β-scission processes, which favors the formation of branched alkanes, while suppressing competing reactions that produce straight-chain alkanes.
能提高汽油辛烷值的支链烷烃可由废弃聚乙烯制备。然而，在废弃聚乙烯的升级循环利用中，实现支链烷烃的高选择性生产是一项重大挑战。在此，我们报道了一种一锅法工艺，可在280°C下，以SO/ZrO-AlO为催化剂，将聚乙烯转化为汽油馏分烃（C-C），产率达73.3%。在C-C馏分中，支链烷烃的比例达到90.1%。硫酸根的引入赋予催化剂强路易斯酸位点以及弱和中等强度的布朗斯特酸位点。原位X射线吸收、原位红外光谱、原位小角中子散射和密度泛函理论计算表明，聚乙烯的活化是通过硫酸根与强路易斯酸位点（Zr位点）之间的协同作用实现的。弱和中等强度的布朗斯特酸位点优先催化异构化和A型β-断裂过程，这有利于支链烷烃的形成，同时抑制产生直链烷烃的竞争反应。
