A Novel Gemini Sulfonic Ionic Liquid Immobilized MCM‐41 as Efficient Catalyst for Doebner‐Von Miller Reaction to Quinoline

Abstract A novel 2,2′‐bipyridine‐based gemini sulfonic ionic liquid was first synthesized and then immobilized on MCM‐41 support (named IL1/MCM‐41), which was further characterized using XRD, FT‐IR, SEM, TEM, N 2 ‐physisorption, XPS and TG techniques. These characterization results revealed that the IL1/MCM‐41 presented a whole ordered mesoporous structure, excellent thermal stability as well as the interaction between ionic liquid with MCM‐41. Catalytic activity of the obtained IL1/MCM‐41 was systematically evaluated for the Doebner‐Von Miller reaction to generate quinoline. Compared to conventional imidazole‐type single sulfonic ionic liquid supported on MCM‐41 (named IL2/MCM‐41), IL1/MCM‐41 exhibited higher catalytic activity and better reusability, which was probably due to the synergistic catalytic effect of the dual sulfonic acid group on IL2 and the stronger interaction between dipyridine ring of ionic liquid with MCM‐41 support, respectively. Meanwhile, a plausible reaction routes for the synergistic catalytic action of dual sulfonic acid to quinoline over the IL1/MCM‐41 catalyst was also proposed in this paper.