Magnetic reusable nanocatalysts in cyanation reactions: a sustainable and efficient pathway to nitriles synthesis

Nitriles are among the most important functional groups in modern organic chemistry because they are widely used in pharmaceuticals, agrochemicals, dyes, advanced materials, and numerous industrial products. Cyanation reactions remain among the most efficient methods for introducing the cyano (–C≡N) group into organic molecules. However, traditional cyanation processes often involve toxic cyanide reagents, harsh reaction conditions, difficult catalyst separation, and environmental concerns. In recent years, magnetic reusable nanocatalysts have emerged as attractive alternatives due to their unique ability to combine high catalytic efficiency with simple magnetic recovery and excellent recyclability. This review highlights recent progress in the development of magnetic nanocatalysts for nitrile synthesis through cyanation reactions. Various catalytic systems based on Fe₃O₄, γ-Fe₂O₃, and CoFe₂O₄ magnetic supports functionalized with palladium, copper, cobalt, zinc, gold, and organocatalytic active species are comprehensively discussed. The review covers catalyst design, synthesis, characterization, substrate scope, reaction optimization, catalytic mechanisms, and recycling performance. Special attention is given to sustainable and environmentally friendly approaches. These include safer cyanide sources such as K₄[Fe(CN)₆], TMSCN, nitromethane, and ammonium formate, as well as green solvents and mild reaction conditions. Most of the reported catalytic systems exhibited excellent yields, broad functional-group tolerance, low metal leaching, and efficient recyclability over multiple cycles. Overall, magnetic reusable nanocatalysts represent highly promising and sustainable tools for modern nitrile synthesis and are expected to play an increasingly important role in green industrial and pharmaceutical chemistry.