正构烷烃临氢异构化催化剂研究进展

随环保法规和燃料质量要求逐步严格，作为生产高辛烷值汽油、低凝点柴油和高黏度指数润滑油的重要工艺技术，正构烷烃临氢异构化反应至关重要。本文综述了临氢异构化反应中的双功能催化剂是由提供加氢/脱氢活性的金属中心和用于骨架异构化的酸性载体组成。介绍了双功能催化剂中不同金属中心和酸性载体的贡献，相对于负载贵金属双功能催化剂，双金属、过渡金属磷化物及稀土掺杂催化剂活性相当，抗硫性高，成本低。此外，介微孔分子筛不仅具有易于反应物和产物扩散的较大孔径，还具有适宜酸性，能够促进骨架异构化，用于临氢异构化催化剂的载体而受到广泛关注。最后探讨了影响双功能催化剂异构化性能主要因素取决于金属和酸性载体之间的平衡，即金属中心和酸中心比例及距离。当催化剂存在适宜金属中心/酸中心比例，且金属-酸中心距离处于纳米级范围时，催化活性和异构化产物选择性会更高。

Development of catalyst for n-paraffins hydroisomerization

With the increasing strictness of environmental regulation and fuel quality requirements, the hydroisomerization of n-paraffins for producing high-octane gasoline, low-freezing point diesel and high-viscosity index lubricating oil, becomes more and more important. This review summarizes the bifunctional catalysts for the hydroisomerization reaction, which were mainly composed of a metal center to provide hydrogenation/dehydrogenation activity and an acidic support for skeletal isomerization. The contributions of different metal centers and acidic supports in dual-functional catalysts are introduced. Compared with bifunctional catalysts loaded with precious metals, catalysts doped by bimetallic, transition metal phosphides and rare earth have similar activity, higher sulfur resistance and lower cost. Moreover, mesoporous molecular sieve with large pore size is beneficial to the diffusion of reactants and products, and has high acidity, which promotes the skeleton isomerization. Therefore, it attracts extensive attentions from researchers. Finally, the main factor affecting the isomerization performance of dual-functional catalyst is the balance between the metal and the acidic support, that means, the ratio and distance between the metal center and the acid center. The catalysts with a suitable metal center/acid center ratio and a nano scale metal-acid center distance should have high catalytic activity and isomerization product selectivity.