Imidazolium Sulfonic Acid Chloride Ionic Liquid Functionalized NiS-Graphitic Carbon Nitride as a Solid Acid-Base Bifunctional Catalyst for Knoevenagel Condensation Reactions

The development of rational acid-base bifunctional heterogeneous catalysts for organic transformation reactions is a challenging procedure. An imidazolium sulfonic acid chloride ionic liquid immobilized NiS doped graphitic carbon nitride (NiS-gC(3)N(4)-IL) catalyst that is very effective, non-toxic, inexpensive, and capable of both acid and base reactions has been prepared. As prepared NiS-gC(3)N(4)-IL catalyst has a high catalytic potential for the Knoevenagel condensation reaction. In addition to the basic nature of the NiS-gC(3)N(4)-IL catalyst due to the existence of N-containing moieties, the acidic nature of the catalyst is also contributed by -SO3H groups of ionic liquid. These properties make this catalyst function as both acid as well as a base catalyst. The structural and morphological properties of the synthesized catalyst were thoroughly explored. The polycrystallinity of the amorphous g-C3N4 was produced as a result of the functionalization of ionic liquid. The remarkable catalytic activity of the NiS-gC(3)N(4)-IL nanosheets is demonstrated by the high yields of the products in less time and at optimal temperatures. The NiS-gC(3)N(4)-IL catalyst is highly efficient towards Knoevenagel condensation of nitrobenzaldehyde with 98% yield using ethanol as solvent. In addition, the catalyst showed exceptional recyclability and reusability. The catalyst is environmentally friendly, and the process is sustainable.

Automated summary

In this study, a new NiS-gC(3)N(4)-IL catalyst with efficient acid-base bifunctionality and excellent catalytic activity was prepared. The catalyst offers a potential application in organic synthesis as an environmentally friendly and sustainable choice.