Highly efficient catalytic hydrocracking of lignite through selective cleavage of aryl C-O bonds to produce valuable fuels and chemicals is a prospective but challenging approach. Catalytic hydrocracking reactions of lignite and lignite-related model compounds were performed over a Ni-based catalyst. The results demonstrated that the aryl C-O bonds in benzyl phenyl ether and dinaphthyl ether were preferentially cleaved and the resulting aromatic monomers were subsequently hydrogenated with continuous optimization of reaction conditions. Moreover, a complete conversion of model compounds and 100 % selectivity of monomeric products were achieved. The density functional theory calculations unraveled that the stable horizontal adsorption of both benzene rings in benzyl phenyl ether at Ni sites can reduce the electron cloud density around ether-oxygen bonds and weaken their dissociation energy, facilitating the dominant cleavage of aryl C-O bonds. Component analyses and structural characterizations indicated that aromatic hydrocarbons were mainly produced (50.02 %) after catalytic hydrocracking of lignite through the selective cleavage of C-O bonds, effective removal of oxygen-containing structure and cracking of side chain groups on aromatic rings. Most significantly, this study proposed the probable mechanism that H+ species originating from the heterolytic cleavage of H2 and H···H were the main active hydrogen species, committing to cracking C-O bonds, while H···H species were tendentious for subsequent hydrogenation of aromatic rings.

中文翻译：

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通过选择性裂解芳基 C-O 键对内蒙古东部褐煤和褐煤相关模型化合物进行高效催化加氢裂化


通过选择性裂解芳基 C-O 键对褐煤进行高效催化加氢裂化以生产有价值的燃料和化学品是一种有前途但具有挑战性的方法。褐煤和褐煤相关模型化合物的催化加氢裂化反应在 Ni 基催化剂上进行。结果表明，苄基苯基醚和二萘基醚中的芳基 C-O 键被优先裂解，随后通过不断优化反应条件，得到的芳香族单体被氢化。此外，还实现了模型化合物的完全转化和单体产物的 100% 选择性。密度泛函理论计算揭示了两个苯环在苄基苯醚中 Ni 位点的稳定水平吸附可以降低醚-氧键周围的电子云密度并减弱其解离能，促进芳基 C-O 键的显性断裂。组分分析和结构表征表明，褐煤催化加氢裂化后，通过选择性裂解 C-O 键、有效去除含氧结构和芳香环上的侧链基团开裂，主要产生芳烃 （50.02 %）。最重要的是，本研究提出了 H+ 物种起源于 H2 和 H···H 是主要的活性氢种类，致力于破解 C-O 键，而 H···H 种类对芳香环的后续氢化具有倾向性。