Sulfonic acid functionalized SBA-15 nanoporous material (SBA-Pr-SO3H) with a pore size of 6 nm was found to be a green and effective solid acid catalyst in the one-pot synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions. SBA-Pr-SO3H was proved to be a recyclable, green, and highly efficient catalyst which could be easily handled, recovered, and reused several times without significant loss of reactivity.
Mohammadi Ziarani, G., Badiei, A., Lashgari, N., & Farahani, Z. (2016). Efficient one-pot synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles using SBA-Pr-SO3H as a green nano catalyst. Journal of Saudi Chemical Society, 20(4), 419–427. https://doi.org/10.1016/j.jscs.2013.01.005