Pd–Cu Bimetallic Catalyst on Amidoxime Fiber Realizing an Alternative and High-Efficient Cyanation of Aryl Halide

Abstract

The reaction of aryl halide cyanation through safe, efficient and stable pathway is of great significance in the industry of fine chemicals. Here, using potassium ferrocyanide and Pd–Cu bimetallic catalyst supported on amidoxime fibers (Cu(I)Pd(II)-AOFs), we propose an alternative reaction pathway for aryl halide cyanation. It shows that a high catalytic activity of cyanation is over 90% for aryl bromides/iodides and about 50% for aryl chlorides at reaction time (2 h), heating reflux in DMAc, in air. The morphology, composition and structure of the prepared catalysts are characterized by SEM, XRD and XPS. The changes of binding energy (N1s O1s Pd3d) show that Pd(II) ions is coordinated with the –NH₂/–OH in AOFs, and that Pd(0) and Cu(II) are detected on the surface of AOFs after reaction. These results indicate that CuI makes Pd²⁺ reduce to Pd⁰ so as to produce activity central, and that AOFs coordination action is to enhance Pd⁰ central activity, and that CuI promotes the cyanide ion in potassium ferrocyanide dissociation. A high-efficient cyanation of aryl halide is successfully achieved by the synergistic action with the three actions.

Graphical Abstract