New insights into the exploitation of oxidized carbon nitrides as heterogeneous base catalysts

In this work, the development of a novel efficient heterogeneous catalytic system capable of driving Knoevenagel condensation reactions between benzaldehydes and malononitrile was reported. Specifically, we explored a postsynthetic modification of graphitic carbon nitride (g-CN) through a strong oxidation treatment by acid mixture (HNO3/H2SO4). The as-prepared oxidized CN material (CNO) shows a large number of surface acidic moieties, that can be easily depmtonated through an aqueous alkaline wash with different bases (NaOH, K2CO3, t-BuOK), to introduce a high density of reactive basic sites. The best catalyst is obtained with NaOH as the base (CNO-NaOH), and displays high reactivity and good tolerance towards functional group variations of the reagents, thus emerging as a potential new recyclable carbon nitride-based structure for organic base catalysis.

Automated summary

The study developed an efficient heterogeneous catalytic system for driving Knoevenagel condensation reactions between benzaldehydes and malononitrile. The catalyst, CNO-NaOH, showed high reactivity and good tolerance towards functional group variations of the reagents, making it a potential new recyclable structure for organic base catalysis.