Mesoporous silica materials with different pore structures and sizes have been used for supporting aryl sulfonic acid catalytic sites via a postsynthetic grafting approach. The synthesized materials have been evaluated in the solventless acid-catalyzed self-condensation of cyclohexanone (CHO) to obtain the corresponding C₁₂ adducts. These compounds display great potential as oxygenated fuel precursors as they can be transformed into jet fuel range alkanes in a subsequent hydrodeoxygenation process. In this work, the synthesized catalysts have displayed high selectivity values toward monocondensed compounds (>95%), thus limiting the formation of undesired heavier condensation products, together with CHO conversion values in the range 20–40% after 2 h of reaction at 100 °C. The structural and textural properties of the supports play an important role in the catalytic performance. Moreover, the activity per acid center is correlated with the textural properties of the supports, indicating that a lower surface density of the anchored aryl sulfonic groups affords an improvement in their specific activity. Finally, the benefit of using supports with large pore sizes and open structures, which limit the fouling of the catalysts by organic deposits, is demonstrated in a stability and reusability test.

中文翻译：

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环己酮在磺酸改性二氧化硅上高效自缩合为生物喷气燃料前体：孔径和结构影响的见解


具有不同孔结构和尺寸的介孔二氧化硅材料已被用于通过后合成接枝方法负载芳基磺酸催化位点。合成的材料已在环己酮（CHO）的无溶剂酸催化自缩合反应中进行了评价，以获得相应的C ₁₂加合物。这些化合物显示出作为含氧燃料前体的巨大潜力，因为它们可以在随后的加氢脱氧过程中转化为喷气燃料系列烷烃。在这项工作中，合成的催化剂对单缩合化合物表现出高选择性值（>95%），从而限制了不需要的较重缩合产物的形成，并且在 100 ℃下反应 2 小时后，CHO 转化率在 20-40% 范围内。 °C。载体的结构和织构特性对催化性能起着重要作用。此外，每个酸中心的活性与载体的结构性质相关，表明锚定的芳基磺酸基团的较低表面密度可提高其比活性。最后，在稳定性和可重复使用性测试中证明了使用具有大孔径和开放结构的载体的好处，这限制了有机沉积物对催化剂的污染。