A Brønsted‐acidic ionic liquid gel was prepared from 1‐(4‐sulfonic acid)butyl‐3‐methylimidazolium hydrogen sulfate and tetraethoxysilane. Its structural characterization was accomplished by FTIR, TGA, SEM, EDS, and ICP‐OES. The ionic liquid gel promotes the synthesis of bis(indolyl)methanes. Interestingly, this catalyst allows the preparation of bis(indolyl)methanes in good to excellent yields within a short reaction time, through a clean and straightforward procedure. Moreover, the ionic liquid gel can be recovered by filtration and can be reused up to 5 times without any detectable loss of catalytic performance. Additionally, the method has a wide substrate scope and provides an accessible route for the large‐scale direct synthesis of bis(indolyl)methanes.

中文翻译：

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一种Brønsted-Aicic离子液体凝胶，可在无溶剂声波作用下合成双（吲哚基）甲烷，是一种高效且可回收的多相催化剂

用1-（4-磺酸）丁基-3-甲基咪唑鎓硫酸氢盐和四乙氧基硅烷制备了Brønsted-酸性离子液体凝胶。它的结构表征是通过FTIR，TGA，SEM，EDS和ICP-OES完成的。离子液体凝胶促进双（吲哚基）甲烷的合成。有趣的是，该催化剂允许通过清洁和直接的程序在短的反应时间内以良好的产率至优异的产率制备双（吲哚基）甲烷。而且，该离子液体凝胶可以通过过滤回收，并且可以重复使用多达5次，而没有任何可检测到的催化性能损失。此外，该方法具有广泛的底物范围，并为大规模直接合成双（吲哚基）甲烷提供了一种可行的途径。