Silica Supported Ionic Liquid CuCl3-IL-SiO2: A Novel and Highly Efficient Catalyst for Ullmann C-N and C-O Cross-coupling Reactions Under Mild Conditions

Silica supported functionalized ionic liquid CuCl3-IL-SiO2 has been prepared and characterized by FTIR, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC) analysis. A series of arylamines and aryl ethers were obtained by Ullmann C-N and C-O coupling of aryl halides with amines and phenols catalyzed by this ionic liquid. The reactions were carried out with aryl halide (10 mmol), amine or phenol (10 mmol), CuCl3-IL-SiO2 (1.5 mol %), K2CO3 (11 mmol), and CH3CN (20 mL) at reflux conditions. This atom economical protocol affords the target products in good to high yields. The properties of the heterogeneous catalytic system were studied by tuning various reaction parameters including amount of the catalyst, influences of solvents and bases. The catalyst exhibited high efficiency in the Ullmann coupling reactions along with good recycle performance. The salient features of the present protocol are mild reaction conditions, shorter reaction time, easy recoverability and steady reuse.