With a motivation of improving accessibility for mass transport of sterically bulky molecules, we demonstrate the synthesis of mesoporous Y zeolite catalysts with increased pore size. Our supramolecular approach relies on the swelling of surfactant assemblies with organic molecules, such as 1,3,5-trimethylbenzene (TMB), -xylene (-xylene), and 1,4-diisopropylbenzene (DIPB), as well as cosolvents consisting of ethanol and -butyl alcohol (TBA). With both trimethylalkylammonium bromide (CTAB, n = 16 and 18) surfactants investigated, TMB exhibits a stronger swelling effect compared with both -xylene and DIPB, which suggests an optimum in the hydrophobicity of the swelling agent. Cosolvents such as TBA and ethanol act as pore-size and porosity property modulators, with TBA exhibiting a greater degree of mesopore expansion than ethanol. Our optimized material consisted of a mesopore size of 6.8 nm and a mesopore volume of 0.41 cm/g, which was synthesized with a TMB/CTAB ratio of 12. The catalytic results of Friedel Crafts Acylation (FCA) of 2-methoxynaphthalene (2-MN) reaction prove that the synthesis of the larger mesopores via swelling in this material preserves accessibility of catalytic sites. The addition of swelling agents and cosolvents decreases the mesopore volume as a result of a lower NaOH activity, and conducting syntheses with a higher NaOH concentration compensates for this. The effects of mesopore expansion could not be achieved postsynthetically, by treating an as-made conventional mesoporous Y material with TMB swelling agent. This emphasizes the importance of retaining flexibility in the surfactant assembly when performing mesopore expansion via swelling that is driven by non-covalent interactions.

中文翻译：

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介孔 Y 型沸石扩孔的超分子方法

为了提高空间大分子传质的可及性，我们展示了孔径增大的介孔 Y 沸石催化剂的合成。我们的超分子方法依赖于表面活性剂组装体与有机分子的溶胀，例如 1,3,5-三甲苯 (TMB)、-二甲苯 (-二甲苯) 和 1,4-二异丙苯 (DIPB)，以及由以下组成的共溶剂乙醇和正丁醇(TBA)。在研究的两种三甲基烷基溴化铵（CTAB，n = 16 和 18）表面活性剂中，与二甲苯和 DIPB 相比，TMB 表现出更强的溶胀效果，这表明溶胀剂的疏水性最佳。 TBA 和乙醇等共溶剂充当孔径和孔隙率性质调节剂，其中 TBA 表现出比乙醇更大程度的中孔扩张。我们优化的材料由介孔尺寸为 6.8 nm、介孔体积为 0.41 cm/g 组成，其合成时 TMB/CTAB 比为 12。 2-甲氧基萘 (2- MN）反应证明，通过该材料的膨胀合成较大的中孔保留了催化位点的可及性。由于 NaOH 活性较低，添加溶胀剂和共溶剂会降低中孔体积，而用较高 NaOH 浓度进行合成可以弥补这一点。通过用TMB溶胀剂处理制成的常规介孔Y材料，无法在合成后实现介孔扩张的效果。这强调了在通过非共价相互作用驱动的膨胀进行介孔扩张时保持表面活性剂组装体的灵活性的重要性。