To enhance the gasoline octane number, low-octane linear n-alkanes should be converted into their high-octane di-branched isomers via n-alkane hydroisomerization. Therefore, hierarchical SAPO-11-based catalysts are prepared by adding different contents of sodium dodecylbenzene sulfonate (SDBS), and they are applied in n-nonane hydroisomerization. When n(SDBS)/n(SiO₂) is less than or equal to 0.125, the synthesized hierarchical molecular sieves are all pure SAPO-11, and as the SDBS content increases, the submicron particle size decreases, and the external surface area (ESA) increases. Additionally, these hierarchical SAPO-11 have smaller submicron particles and higher ESA values than conventional SAPO-11. When n(SDBS)/n(SiO₂) is greater than 0.125, with increasing SDBS content (n(SDBS)/n(SiO₂) = 0.25), the synthesized SAPO-11 contains amorphous materials, which leads to a decline in the ESA; with the further increase in SDBS content (n(SDBS)/n(SiO₂) = 0.5), the products are all amorphous materials. These results indicate that in the case of n(SDBS)/n(SiO₂) = 0.125, the synthesized SAPO-11 molecular sieve (S–S₃) has the most external Brønsted acid centers and the highest ESA of these SAPO-11, and these advantages favor generation of the di-branched isomers in hydrocarbon hydroisomerization. Among these Pt/SAPO-11 catalysts, Pt/S–S₃ displays the highest selectivity to entire isomers (83.4%), the highest selectivity to di-branched isomers (28.1%) and the minimum hydrocracking selectivity (15.7%) in n-nonane hydroisomerization.

为了提高汽油辛烷值，应通过正烷烃加氢异构化将低辛烷直链正构烷烃转化为高辛烷值二支链异构体。因此，通过添加不同含量的十二烷基苯磺酸钠（SDBS）制备分级SAPO-11-基催化剂，并将其用于正壬烷加氢异构化。当n（SDBS）/ n（SiO ₂）小于或等于0.125时，合成的分级分子筛均为纯SAPO-11，并且随着SDBS含量的增加，亚微米粒径减小，并且外表面积（ ESA）增加。此外，与传统的SAPO-11相比，这些分层的SAPO-11具有更小的亚微米颗粒和更高的ESA值。当n（SDBS）/ n（SiO ₂）大于0.125，随着SDBS含量的增加（n（SDBS）/ n（SiO ₂）= 0.25），合成的SAPO-11包含非晶态材料，导致ESA下降; 随着SDBS含量的进一步增加（n（SDBS）/ n（SiO ₂）= 0.5），产物均为非晶态材料。这些结果表明，在n（SDBS）/ n（SiO ₂）= 0.125的情况下，合成的SAPO-11分子筛（S–S ₃）具有这些SAPO-11中最外部的布朗斯台德酸中心和最高的ESA，这些优点有利于烃加氢异构化过程中生成双支链异构体。在这些Pt / SAPO-11催化剂中，Pt / S–S ₃对整个异构体的选择性最高（83.4％），对二支链异构体的选择性最高（28.1％），在n中的最小加氢裂化选择性（15.7％）。-壬烷加氢异构化。