Super Lewis acids containing the triflate anion [e.g., Hf(OTf)₄, Ln(OTf)₃, In(OTf)₃, Al(OTf)₃] and noble metal catalysts (e.g., Ru/C, Ru/Al₂O₃) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)₄ and ruthenium‐based catalysts. When a technical lignin derived from a pilot‐scale biorefinery was used, more than 30 wt % of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote deoxygenation reactions catalyzed by super Lewis acids.

中文翻译：

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超级路易斯酸与金属催化剂结合对木质素进行加氢脱氧生产喷气燃料范围的烃

含有三氟甲磺酸根阴离子的超级路易斯酸[例如，Hf（OTf）₄，Ln（OTf）₃，In（OTf）₃，Al（OTf）₃ ]和贵金属催化剂（例如Ru / C，Ru / Al ₂ O ₃）形成有效的催化体系，以高产率从木质素产生饱和烃。在这样的催化体系中，金属三氟甲磺酸酯通过选择性键合到醚氧上而介导了快速的醚键裂解，而贵金属则催化了随后的加氢脱氧（HDO）反应。木质素模型化合物通过Hf（OTf）₄的联合催化生产了接近理论值的烃和钌基催化剂。当使用源自中试规模生物精炼厂的工业木质素时，该催化系统产生的碳氢化合物中有30％以上是喷气燃料范围内的环己烷和烷基环己烷。推测超级路易斯酸通过使羟基和醚键质子化而与木质素底物强烈相互作用，形成中间产物，该中间物质增强了负载型贵金属催化剂的氢化催化作用。同时，贵金属催化剂对芳环的加氢可以促进超级路易斯酸催化的脱氧反应。