Abstract The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging. In this study, acidic poly(ionic liquid)s with swelling ability (SAPILs) were designed and synthesized via the free radical copolymerization of ionic liquid monomers, sodium p-styrenesulfonate, and crosslinkers, followed by acidification. The 31P nuclear magnetic resonance chemical shifts of adsorbed trimethylphosphine oxide indicated that the synthesized SAPILs presented moderate and single acid strength. The thermogravimetric analysis results in the temperature range of 300–345 °C revealed that the synthesized SAPILs were more stable than the commercial resin Amberlite IR-120(H) (245 °C). Cryogenic scanning electron microscopy testing demonstrated that SAPILs presented unique three-dimensional (3D) honeycomb structure in water, which was ascribed to the swelling-induced self-assembly of the molecules. Moreover, we used SAPILs with micron-sized honeycomb structure in water as catalysts for the hydrolysis of cyclohexyl acetate to cyclohexanol, and determined that their catalytic activity was much higher than that of homogeneous acid catalysts. The equilibrium concentrations of all reaction components inside and outside the synthesized SAPILs were quantitatively analyzed using a series of simulated reaction mixtures. Depending on the reaction mixture, the concentration of cyclohexyl acetate inside SAPIL-1 was 7.5–23.3 times higher than that outside of it, which suggested the high enrichment ability of SAPILs for cyclohexyl acetate. The excellent catalytic performance of SAPILs was attributed to their 3D honeycomb structure in water and high enrichment ability for cyclohexyl acetate, which opened up new avenues for designing highly efficient heterogeneous acid catalysts that could eventually replace conventional homogeneous acid catalysts.

中文翻译：

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通过酸性聚（离子液体）的溶胀诱导自组装制备蜂窝结构固体酸催化剂，用于高效水解反应

摘要 开发比均相酸催化剂具有更高活性的非均相酸催化剂是至关重要的，并且仍然具有挑战性。在这项研究中，通过离子液体单体、对苯乙烯磺酸钠和交联剂的自由基共聚，然后酸化，设计并合成了具有溶胀能力的酸性聚（离子液体）（SAPIL）。吸附的三甲基氧化膦的 31P 核磁共振化学位移表明合成的 SAPILs 具有中等和单一的酸强度。在 300–345 °C 温度范围内的热重分析结果表明，合成的 SAPILs 比商业树脂 Amberlite IR-120(H) (245 °C) 更稳定。低温扫描电子显微镜测试表明，SAPILs 在水中呈现出独特的三维 (3D) 蜂窝结构，这归因于分子的溶胀诱导自组装。此外，我们在水中使用具有微米级蜂窝结构的SAPILs作为乙酸环己酯水解为环己醇的催化剂，并确定其催化活性远高于均相酸催化剂。使用一系列模拟反应混合物定量分析合成 SAPIL 内部和外部所有反应组分的平衡浓度。根据反应混合物的不同，SAPIL-1 内部乙酸环己酯的浓度是其外部的 7.5-23.3 倍，这表明 SAPILs 对乙酸环己酯的高富集能力。